Ritron RIT13-144 Handheld FM Transceiver User Manual 144 manC

Ritron Inc Handheld FM Transceiver 144 manC

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User Manual

TYPE OF EXHIBIT: INSTRUCTION MANUALS

FCC PART: 2.1033 (c)

MANUFACTURER: RITRON, INC.

505 West Carmel Drive

Carmel, IN 46032

MODEL: SST-144

TYPE OF UNIT: VHF-FM Handheld Transceiver

FCC ID: AIERIT13-144

DATE: April 25, 2001

Included is a draft of the Maintenance and Operating Manual for RITRON Model Patriot SST-144

VHF-FM Handheld Transceiver.

Specifically, this manual includes a technical description of the SST-144 sufficient to establish

compliance with the technical standards of the applicable rule part(s).

This includes, but is not limited to, the following items required under FCC Part 2.1033 (c):

(2) FCC Identifier.

(3) A copy of the installation and operating instructions.

(4) Type of emission.

(5) Frequency range.

(6) Range of operating power, and means to provide variation in operating power.

(7) Maximum power rating.

(8) DC voltage chart.

(9) Tune-up procedure.

(10) A description of all frequency determining and stabilization circuits. A description of the circuits

used to suppress spurious radiation, limiting modulation, and limiting power.

(12) Drawing with labels for controls and complete circuit diagrams.

Signed:

____________________________________

Kevin G. Matson - Project Engineer

TABLE OF CONTENTS SST-144

TOPIC PAGE

IMPORTANT MAINTENANCE/REPAIR INFORMATION .. 1

SPECIFICATIONS

GENERAL......................................................................... 2

CONTROLS ...................................................................... 2

TRANSMITTER................................................................. 2

RECEIVER........................................................................ 3

BATTERY ......................................................................... 3

INTRODUCTION

GENERAL......................................................................... 4

Model Identification ..................................................... 4

FCC REGULATIONS

Licensing..................................................................... 4

Safety Standards......................................................... 4

BATTERY CARE

CHARGING....................................................................... 5

PRECAUTIONS ................................................................ 5

BATTERY REPLACEMENT.............................................. 5

Fig. 1 Battery Replacement......................................... 5

BATTERY MAINTENANCE............................................... 6

BATTERY CONDITIONING .............................................. 6

OPERATION

DESCRIPTION OF CONTROLS AND CONNECTORS..... 7

Fig. 2 Controls and Accessory Connectors.................. 7

RADIO OPERATION

On-Off/Volume ............................................................ 8

Receive....................................................................... 8

Selective Signaling Squelch ........................................ 8

Monitor........................................................................ 8

Battery Saver .............................................................. 8

Transmit...................................................................... 8

Channel Selection ....................................................... 8

WHAT THE RADIO TONES MEAN

Power On/Self Check “OK........................................... 9

Error Tones ................................................................. 9

Channel Select............................................................ 9

Tone Squelch.............................................................. 9

Recharge Battery Alert ................................................ 9

OPTIONAL RADIO TONES

Receiver Squelch Tone ............................................... 9

Busy Channel Inhibit ................................................... 9

Transmitter Time Out .................................................. 9

BELT CLIP INSTALLATION.............................................. 9

TROUBLESHOOTING

General ..................................................................... 10

Battery ...................................................................... 10

Error Tones ............................................................... 10

Tone Coded Squelch................................................. 10

PROGRAMMING THE RADIO

PTT (PUSH-TO-TALK) PROGRAMMING

Fig. 3 Placing the Radio in Program / Readout Mode 11

Reading Out a Radio Channel’s Content................... 11

PTT Programming the Radio..................................... 12

Return To Normal Operation ..................................... 12

PTT Programming Mistakes...................................... 12

Table 1 – PTT Programming Frequency Table.......... 13

Table 2 – Quiet Call Codes and Frequencies ............ 13

COMPUTER SOFTWARE COPYRIGHTS ...................... 13

PC COMPUTER PROGRAMMING ................................. 13

Programmable Features............................................ 14

Description of Features ............................................. 15

TOPIC PAGE

THEORY OF OPERATION

INTRODUCTION .............................................................16

POWER SUPPLY AND VOLTAGE DISTRIBUTION........ 16

Power Strobe.............................................................16

Low Battery Voltage Detection...................................16

REFERENCE OSCILLATOR ...........................................16

SYNTHESIZER ..............................................................16

Pin Numbers..............................................................16

Prescaler Divider / Synthesizer Controller..................16

VCO / Buffer Amplifiers .............................................17

Oscillator Modulation ................................................. 17

DIGITAL POTENTIOMETERS......................................... 17

RECEIVER ......................................................................17

RF Amplifier...............................................................17

1st Mixer.................................................................... 18

FM Receiver Subsystem............................................ 18

Voice / Tone Conditioning in Receiver Mode .............18

Voice Band ................................................................18

Sub-Audible............................................................... 18

Audio Amplifier .......................................................... 18

ANTENNA SWITCHING / LOW-PASS FILTER............... 19

TRANSMITTER ............................................................... 19

Keying .......................................................................19

+VTX Supply..............................................................19

Power Amplifier ......................................................... 19

Voice/Tone Conditioning in Transmit Mode ...............19

Voice Band ................................................................19

Sub-Audible............................................................... 19

MICROCONTROLLER ....................................................20

ALIGNMENT PROCEDURE

RECOMMENDED TEST EQUIPMENT............................ 21

RADIO PREPARATION...................................................21

REFERENCE FREQUENCY ........................................... 21

MODULATION BALANCE ...............................................22

TRANSMITTER TONE DEVIATION ................................ 22

TRANSMITTER VOICE DEVIATION...............................22

TRANSMITTER POWER.................................................22

RECEIVER SENSITIVITY AND SQUELCH.....................23

RECEIVER NOISE SQUELCH........................................23

SYNTHESIZER ...............................................................23

VOLTAGE CHART

Measurement Conditions................................................. 24

SST-144 Voltages ...........................................................24

PARTS LIST

SCHEMATIC REFERENCE PARTS LIST .......................27

CASE ASSEMBLY PARTS LIST .....................................33

SCHEMATIC AND PART PLACEMENT DRAWINGS

TOP SIDE PART PLACEMENT....................................... 35

BOTTOM SIDE PART PLACEMENT............................... 36

SCHEMATIC – UHF RF ..................................................37

SCHEMATIC – Signal Processing ................................... 38

IMPORTANT REPAIR / MAINTENANCE INFORMATION SST-144

Surface Mount Repair

RITRON surface mount products require special

equipment and servicing techniques. Improper

servicing techniques can cause permanent damage

to the printed circuit boards and/or components,

which is not covered by RITRON’s warranty. If you

are not completely familiar with surface mounted

component repair techniques, RITRON recommends

that you defer maintenance to qualified service

personnel.

Precautions for Handling CMOS Devices

This radio contains complementary metal-oxide

semiconductor (CMOS) devices, which require

special handling techniques. CMOS circuits are

susceptible to damage by electrostatic or high voltage

charges. Damage can be latent, with no failure

appearing until weeks or months later. For this

reason, take special precautions any time you

disassemble the radio. Follow the precautions below,

which are even more critical in low humidity

environments.

1) Storage/transport - CMOS devices that will be

stored or transported must be placed in

conductive material so that all exposed leads are

shorted together. CMOS devices must not be

inserted into conventional plastic “snow” or

plastic trays of the type that are used for other

semiconductors.

2) Grounding - All CMOS devices must be placed

on a grounded bench surface. The technician

that will work on the radio/CMOS circuit must be

grounded before handling the radio. Normally,

the technician wears a conductive wrist strap in

series with a 100K Ohm resistor to ground.

3) Clothing - Do not wear nylon clothing while

handling CMOS circuits.

4) Power off - Remove power before connecting,

removing or soldering a PC board that contains

CMOS devices.

5) Power/voltage transients - Do not insert or

remove CMOS devices with power applied.

Check all power supplies to be used for testing

CMOS devices, making sure that no voltage

transients are present.

6) Soldering - Use a grounded soldering iron for

soldering CMOS circuitry.

7) Lead-straightening tools - When straightening

CMOS leads, provide ground straps for the tool

used.

PC Board Removal - Special Tool

RITRON recommends using a knurled nut tool to

remove the slotted knurled nuts that secure the

charge and audio jacks on top of the radio. You will

need two sizes of this tool, one for each jack size.

Mouser Corporation  is one source, stock number

382-0004 (2.5mm jack) and 382-0006 (3.5mm jack).

You can reach Mouser sales and distribution center

at 1-800-346-6873.

Properly Attach the Synthesizer Shield

The synthesizer shield should not be removed, unless

a component must be replaced. This shield is

soldered to the main PC board.

Re-assembly - Speaker Magnet, Battery Voltage

on Connector Pin

The speaker magnet will pick up clipped leads and

other small metal objects from your bench top. Even

tiny objects on the diaphragm will cause the speaker

to buzz. Make sure the speaker is free of foreign

objects before reassembling the radio.

Radio Transmitter Power Measurements

The SST-144 was designed to produce 4 Watts of

Transmitter power at nominal battery voltage (+7.2

VDC), throughout the radio’s operating frequency

range. Measurements are made with the RITRON

SST-SRVBD RF service module connected to the

radio antenna terminal. The transmitter was

designed with close tolerances to prevent RF power

output from exceeding specifications and reducing

battery life.

PCB and Firmware Revisions

Changes in circuit design, component values, and

radio firmware are made occasionally to enhance the

performance of the SST-144. In general, the manual

will be periodically updated for component value

changes without a change in the manual revision

level. Always refer to the Schematic Reference Parts

List for the most recent component values. Changes

in circuit design that require printed circuit board

revision, or changes in firmware that significantly alter

the operating characteristics of the radio, will be

covered in a revised manual.

This manual is updated for the following revisions:

SST-144-MRM Rev A

PCB Revision 1750250C

Firmware Revision v06

SPECIFICATIONS SST-144

GENERAL

FCC ID: AIERIT13-144

FCC Rule Parts: 22, 74, 90, 95

Frequency Range: 150 to 162 MHz

Max. Freq. Separation: 12 MHz

RF Channels: Up to 10 Channels,

Independent TX/RX

frequencies.

Synthesizer Step Size:5 KHz

Frequency Stability: +/-2.5 PPM (-30 to +60 C)

TX/RX

Tone/Code Signaling: CTCSS (Quiet Call)

Digital Coded Squelch

(Digital Quiet Call)

Dimensions: 4.75”H x 2.2”W x 1.43”D

Weight: 11.5 oz. with battery pack

Enclosure Material: Lexan Polycarbonate

Environmental: Splash resistant and

shock and vibration per

RITRON Drop Test (6 ft.

drop onto concrete on all

six sides)

Antenna Fitting: 1/4" - 32 x 1/4" threaded

External RF Test Jack: Antenna connector with

RITRON SST-SRVBD test

device

Earphone Jack: 3.5 mm, disconnects the

internal speaker for

external earphone,

speaker / microphone, or

headset. Also provides

cable connection for PC

programming.

Microphone/PTT/ 2.5 mm, for external

Chg Jack: speaker/microphone,

headset or RITRON model

BC-A wall charger.

CONTROLS

Push Button Controls: On/Volume Up, Volume

Down/Off, PTT, Channel

Speaker Beep Indicators:

On/Volume Up: Radio beeps channel

number when turned on,

followed by increasing

audio to adjust volume.

Volume Down/Off: Decreasing audio to adjust

volume, with two tones

when turned off.

Both Volume Buttons: Alternates between Tone

Squelch (single beep) and

Carrier Squelch (two

beeps). If both buttons

are held down until the

radio beeps repeatedly,

squelch will be disabled.

PTT: Programmable for a single

“transmit beep”.

Channel: Number of beeps indicates

channel.

TRANSMITTER

RF Power Output: Programmable per

channel for high or low

power

High : 4 Watts @ +7.2 VDC

Low: 1 Watt

Wide Mode Narrow Mode

Emission Designator: 16K0F3E 11K0F3E

Deviation: +/- 5.00 KHz +/- 2.50 KHz

FM Hum and Noise: -46 dB -40 dB

Audio Distortion:< 3 %

Spurious & Harmonics: -60 dBc

Audio Response: Meets FCC and EIA

requirements

Time-out Timer: 60 seconds,

programmable

SPECIFICATIONS SST-144

RECEIVER

Wide band Narrow band

Models Models

Modulation Acceptance: +/- 7.0 KHz +/- 3.75 KHz

Sensitivity: 0.25 µV 0.25 µV

(12 dB SINAD)

Adjacent Channel (EIA): -75 dB -65 dB

Spurious Rejection: -70 dB -70 dB

Image Rejection (EIA): -80 dB -80 dB

Intermodulation (EIA): -65 dB -60 dB

Noise Squelch Programmable per

Sensitivity: channel, factory set for 12

dB SINAD

Frequency Response: 300 - 3000 Hz, de-

emphasized

Audio Output 1 Watt into 8 Ω, with less

than 5 % THD @ the

earphone jack

Receiving System: Dual conversion

superheterodyne

I.F. System: 1st - 43.65 MHz,

2nd - 450 KHz

L.O. Injection: High side

QC/DQC Decode Time: per EIA Standards

BATTERY

Battery Pack: +7.2 VDC, 800 mAH

rechargeable NiCd battery

pack standard

+7.2 VDC, 1500 mAH

rechargeable MiMH

battery pack optional

Battery Drain:

Standby: 46 mA

Sleep: 12 mA

Avg. Standby

with Power Saver: 20 mA

Receive: 125 mA

Transmit: 1600 mA @ 4 Watts

850 mA @ 1 Watt

Battery Life @ 90/5/5 Duty Cycle with

Standard battery pack (800 mAH):

8.3 Hrs, Battery Saver On, TX High Power

15.7 Hrs, Battery Saver On, TX Low Power

6.5 Hrs, Battery Saver Off, TX High Power

10.2 Hrs, Battery Saver Off, TX Low Power

Battery Life @ 90/5/5 Duty Cycle with

High capacity battery pack (1500 mAH):

15.6 Hrs, Battery Saver On, TX High Power

29.4 Hrs, Battery Saver On, TX Low Power

12.2 Hrs, Battery Saver Off, TX High Power

19.2 Hrs, Battery Saver Off, TX Low Power

INTRODUCTION SST-144

GENERAL

RITRON's SST-144 handheld is a small,

programmable two-way radio, designed to operate in

the 150-162 MHz professional FM communications

band. This handheld features push-button operating

controls, with the Push-To-Talk and Channel buttons

on one side of the radio. The On / Volume Up and

Volume Down / Off, volume and monitor controls are

on top.

Each radio can be “dealer” programmed to contain a

unique set of operating frequencies and options.

Selective signaling options include Quiet Call

(CTCSS) and Digital Quiet Call (DCS). Transmitter

power, operating bandwidth and battery saver are

among the options programmable on a per channel

basis.

Model Identification

The SST-144 model, serial number and FCC

Identification are displayed on a label located on the

back of the radio beneath the belt clip.

FCC REGULATIONS

Licensing

The FCC requires the radio owner to obtain a station

license for his radios before using them to transmit,

but does not require an operating license or permit.

The station licensee is responsible for ensuring that

transmitter power; frequency and deviation are within

the limits specified by the station license. The station

licensee is also responsible for proper operation and

maintenance of the radio equipment. This includes

checking the transmitter frequency and deviation

periodically, using appropriate methods.

Safety Standards

In 1991 the Institute of Electrical and Electronics

Engineers (IEEE), and in 1992 the American National

Standards Institute (ANSI) updated the 1982 ANSI

standard for safety levels with respect to human

exposure to RF energy. Over 120 scientists,

engineers, and physicians from universities,

government health agencies, and industry, after

reviewing the available body of research, developed

this updated Standard. In March 1993 the Federal

Communications Commission (FCC) proposed the

adoption of this updated Standard.

The SST-144 handheld radio is designed to comply

with this Standard. To limit your exposure to levels

at, or below, the levels in the Standard, please

observe the following:

• Use only the antenna(s) available from RITRON

for this model. DO NOT attempt to substitute any

other antenna.

• Keep talk times as short and infrequent as

possible. DO NOT depress the PTT button when

not actually wishing to transmit. The radio is

equipped with an internal timer to limit continuous

transmit times.

• When transmitting, hold the radio in front of the

mouth at a distance of at least 4 inches. DO NOT

hold the radio in such a manner that the antenna

is next to, or touching, exposed parts of the body,

especially the face or eyes while transmitting.

• In belt mounted applications, when transmitting,

remove the radio from the belt and hold away from

the body at least 4 inches.

• When using external headset accessories, hold

the unit away from the body at least 4 inches while

transmitting.

• DO NOT allow children to operate the radio.

BATTERY CARE SST-144

CHARGING

The handheld is powered by a rechargeable battery,

which fits into the radio case (see FIG-1).

The battery pack can lose its charge during storage

and shipment, and should be fully charged before the

radio is used. Thereafter, the battery should be

charged overnight after each day of use, to ensure

peak radio performance for the next day. Using the

cube charger (model BC-A), the battery should

charge completely in 12 hours.

To charge the battery using a RITRON cube charger -

plug the charger cord into the smaller of the two jacks

on top of the radio. Then plug the cube into a 110

VAC outlet. The green lamp lights while the battery is

charging, and should go off only when the cube is

unplugged.

Two charger contacts, visible through the bottom of

the radio case, allow the battery to be charged using

an optional RITRON drop-in charger (model BCC-

PS). The battery pack may be charged inside or

outside of the radio case.

To charge the battery using a drop-in charger (model

BCC-PS) - plug the drop-in charger into a 110 VAC

outlet. Set the portable or battery into the charger.

Each battery contact must rest on a charger contact

pin.

NOTE: A new battery must be cycled (charged and

discharged) several times before it will reach

its maximum charge capacity.

PRECAUTIONS

• Use only RITRON-supplied chargers; other

chargers might cause fire, explosion, or other

damage to the radio.

• Do not "fast-charge" a brand new battery pack.

Otherwise, the battery might be damaged.

• Once the battery has been charged fully using

the normal rate, the fast rate may be used

thereafter.

• Do not fast-charge a battery pack that is fully

charged. This can shorten battery life.

• Do not charge or replace a battery in an

explosive atmosphere. Contact sparking can

ignite an explosion.

• Do not dispose of a battery in fire. An explosion

might result.

• Do not charge the battery in temperatures colder

than about 45°F. Electrolyte leakage can occur

and ruin the battery.

• Charging in temperatures above approximately

95°F will not harm the battery, but can reduce its

charge capacity.

BATTERY REPLACEMENT

To replace the battery in the SST-144:

1. Hold the radio as shown in FIG-1(A)

2. Use your thumbnail to open the Door Latch, as

shown in FIG-1(A).

3. Lift and rotate the Battery Access Door to release

it as shown in FIG-1(B).

4. Use the Pull-tab to pull the Battery Pack out of

the case as shown in FIG-1(C).

5. Insert the replacement Battery Pack as shown in

FIG-1(C). Push the Battery in as far as possible.

6. Replace the Battery Access Door. Secure it by

closing the Door Latch as shown in FIG-1(A).

7. Be certain to firmly lock the Door Latch, as

shown in FIG-1(A).

BATTERY

ACCESS

DOOR

PULL-TAB

FIG-1: Batter

Replacement

(

)

(

)

(

)

LATCH

CLOSED

LATCH

OPEN

BATTERY

ACCESS

DOOR

BATTERY CARE SST-144

BATTERY MAINTENANCE

With daily use and recharging, a battery’s service life

is about one year. To ensure maximum service life,

follow these guidelines:

•DO NOT discharge a battery that is already “run

down.” If the battery cannot power your radio,

recharge the battery.

•DO NOT overcharge a battery. The standard

battery should not be left to charge continuously.

•Condition battery packs once a month as

directed in Battery Conditioning.

•Condition batteries that are run down.

•Charge batteries for 16 hours before storage,

and for 16 hours once a month thereafter.

•DO NOT charge batteries in temperatures colder

than about 45°F. Charging batteries in

temperatures above 95°C. does not harm them,

but can reduce charge capacity.

It is time to purchase a new battery:

•When the radio’s transmitter coverage decreases

or does not work at all.

•When the radio quits working after just a few

hours of use, even with a full overnight charge.

•When the battery is more than two years old.

The date of manufacture is stamped on every

battery. The first two digits indicate the year, the

last two digits the week.

BATTERY CONDITIONING

Due to the extended run time of the SST-144 radio,

some users may never fully discharge the battery

pack during normal use. Achieve maximum battery

life by fully discharging the battery periodically to

condition it.

After exposing the battery pack to many cycles of not

fully discharging it before recharging, the radio may

exhibit reduced battery capacity. This reduced

capacity is evident when, after several hours of use,

battery voltage drops while the radio is transmitting,

causing the radio to emit a dead battery warning tone

and shut itself off.

Condition battery packs by the following procedure as

either a preventive measure, or if you suspect

reduced capacity:

1. Use your radio throughout a normal working day

without charging.

2. Press and hold the On/ Volume Up and Volume

Down/ Off buttons simultaneously for 8 seconds

to place the radio in "open squelch" mode.

3. Release both buttons when you hear the radio

beep rapidly; it will then emit a loud "rushing"

noise. Press On/ Volume Up to maximize this

noise.

4. Put the radio away in a secure place (possibly a

desk drawer), where nothing can press against

the buttons to accidentally turn it off or cause it to

transmit. Allow the radio to run until it shuts off

when the battery is completely discharged. A

typical battery pack may require up to 8 hours to

completely discharge.

5. When the radio has shut off, charge it overnight

for 12-14 hours. The battery will be ready for use

with renewed capacity.

OPERATION SST-144

ON OFF/HOLD

VOLUME

Antenna

Vol Down/Off

On/Vol Up

Audio

Accessory

Jack

Jack Cover

Charge Jack

Speaker

Microphone

Push-to-Talk

Channel

Selector

Battery Access

Door

(Case bottom) Battery Charger

Contacts

(Case bottom)

Fig. 2 Controls and Accessory Connectors

DESCRIPTION OF CONTROLS AND

CONNECTORS

Antenna

The flexible antenna radiates and receives radio

signals. Before using the radio, be sure the

antenna base is threaded fully into the radio’s

antenna bushing.

Use only the antenna(s) available from RITRON

for the SST-144. Do not attempt to substitute

with any other antenna.

On/Volume Up

This button switches on the radio, then increases

the volume if you continue to press.

Volume Down/Off

This button decreases the volume, then shuts off

the radio if you continue to press.

Push-To-Talk

The PTT activates the transmitter, and must be

held down while you talk into the microphone.

Release the PTT button to receive.

Channel Selector

Pressing this button selects the next channel.

When the maximum number of channels is

reached and you press this button, the radio

resets to channel 1.

Audio Accessory Jack

This jack connects speaker audio to optional

accessories, such as a remote speaker/

microphone or an earphone. For accessories

that have a two-plug connector, the smaller plug

is inserted into the charge jack.

This jack is also used to program the radio using

the optional PC programming kit.

Charge Jack

The battery may be charged through this jack

using a standard RITRON wall socket charger

cube. This jack also connects microphone audio

to the optional remote speaker/microphone.

Microphone

The microphone converts your voice into

electrical impulses, which are carried with your

broadcast to receiving radios. Hold the radio

about four inches away and talk into the

microphone while transmitting. Shouting does

not improve the listener’s reception.

Speaker

The speaker allows you to hear calls on your

channel.

Jack Cover

This rubber cover seals out dust and moisture, etc. Snap the

cover into the audio accessory and charge jack openings

when the jacks are not being used.

Battery Access (Case Bottom)

The battery door on the case bottom may be removed to

access the battery. (Refer to the Battery Replacement section

of this manual.)

Drop-in Charger Contacts (Case Bottom)

Two charger contacts in the bottom of the SST-144 radio case

allow the battery pack to be charged using an optional

RITRON drop-in charger (model BCC-PS.)

OPERATION SST-144

RADIO OPERATION

On-off/Volume

To switch on the radio - press the On/Volume Up

button. The radio will beep a number of times equal

to the current channel number.

To adjust the volume - press the volume up button

until you reach the desired level. You should hear

noise and any broadcasts on the channel.

To turn off the radio - press and hold the Off/Volume

Down button until two tones sound.

To determine whether the radio is on - press the

volume down button. If the radio is on, noise or

activity on the channel is heard.

Receive

To hear calls from other users - adjust the volume as

desired. The radio can receive broadcasts while the

Push-To-Talk button is not being pressed. Whether

or not you hear these broadcasts depends upon the

squelch settings.

There are two types of squelch used in the SST-144

portable. First is carrier squelch. This lets you hear

all broadcasts on your channel strong enough for the

radio to detect, and silences noise. Second is one of

the selective signaling or “tone squelch” formats

available on the SST-144. This allows you to screen

out “on-channel” broadcasts that do not carry the

correct code programmed for the radio.

Note: It is possible that the beginning of a call might

be missed while the radio is in battery saver

mode. If this happens, ask the caller to repeat

the message.

Selective Signaling Squelch

To activate tone squelch - simultaneously press both

of the volume buttons. Hold for a second or two

before releasing. When tone squelch is turned on,

the handheld sounds one beep. When carrier

squelch is on, the radio emits a "double beep."

Note: If you continue to hold down the volume

buttons after the beep (or double beep), the

radio will start beeping repeatedly. This

means that squelch is turned off. Release the

buttons. To restore squelch, press and hold

both of the volume buttons until the radio

sounds a beep or double beep.

Monitor

To monitor the channel - press one of the volume

control buttons. When you press the volume up or

the volume down button, squelch turns off and all

radio traffic on the channel (and noise) sounds in the

speaker.

Battery Saver

The handheld has a programmable "battery saver"

feature that conserves battery power. The battery

saver constantly checks the radio's transmitter,

receiver and controls for activity. If a number of

seconds pass without the receiver detecting a call,

and without the user operating a control, this feature

removes power from most of the radio.

During this "off-time," any activity restores full power.

Every few fractions of a second, the battery saver

applies power to the receiver, checking for

broadcasts. It is possible that the first part of an

incoming call might go unheard before activity is

detected and power restored. If this happens, the

caller can repeat his message. Once "radio contact"

is made, normal unhurried conversation can follow.

Transmit

Normally, you should not transmit until no one is

talking on the channel.

To transmit - hold down the Push-To-Talk button and

with the radio four inches away talk into the

microphone. Speak in a normal tone, since talking

louder will not improve the listener’s reception.

Channel Selection

To change channels - press and release the Channel

button. The radio will beep a number of times equal

to the current channel number. Pressing the Channel

button again will increment the channel and the radio

will beep the new channel number. For example, if

you select channel 2, the handheld will beep twice. If

the highest channel number is selected and you

press the Channel button, the radio will reset to

channel 1. A one-channel radio will beep only once

when you press the Channel button.

OPERATION SST-144

WHAT THE RADIO TONES MEAN

The handheld responds to certain instructions by

sounding a beep or series of tones. These tones can

tell you whether the radio is working as you expect.

Power On/Self Check “OK”

When it is first turned on, the radio runs a quick “self

test” to confirm basic functions. The radio then beeps

the number of times equal to the channel number

selected. The radio is then ready to use.

Error Tones

However, if the “self test” detects a diagnostic error,

an error tone sounds. Alternating tones (the second

is longer and lower pitched) indicate the radio

frequency synthesizer is malfunctioning. Turn off the

radio and try again. A long, low-pitched tone means

the battery voltage is too low to operate the radio. In

this case, recharge the battery. If you cannot correct

a problem, consult an authorized Ritron service

facility or Ritron.

Channel Select

When the Channel button is pressed, the radio beeps

a number of times equal to the current channel

number. Pressing the Channel button again will

increment the channel and the radio will beep the

new channel number.

Tone Squelch

When you press and hold both Volume buttons at the

same time, a single beep will sound to indicate that

tone squelch is on. A "double beep" means that

carrier squelch is on.

Recharge Battery Alert

As the battery voltage approaches the minimum

required “operating voltage” the radio will emit a short

beep every minute to alert the user that the battery

will soon need recharging. Once the battery charge

drops below the required "operating voltage," the

radio emits a long, low tone and turns itself off. If you

turn the radio back on, it will beep again and shut

itself off. Recharge the battery.

OPTIONAL RADIO TONES

The SST-144 can be programmed using the RITRON

PC Programmer for optional alert tones.

Receive Squelch Tone

A short tone sounds at the end of each received

transmission to indicate that you may transmit.

Busy Channel Transmit Inhibit

If a user is transmitting on your radio frequency

without your tone, you will not be allowed to transmit.

The radio will beep a series of long, low tones while

the PTT is held down (like a busy signal).

Transmitter Time Out

A low tone followed by a higher-pitched tone sounds

and the transmitter automatically shuts off if you hold

down the PTT button longer than the programmed

Time-out. The radio automatically switches to receive

mode. Authorized service personnel can turn off this

feature.

BELT CLIP INSTALLATION

If you are going to attach the belt clip to the handheld,

follow these instructions:

1. The belt clip is fastened to the radio case back

with the Philips head screw provided. Use the

screw included, since a longer screw might

damage the radio’s electronics.

Do not use petroleum solvents of any kind on the

radio. These can corrode the case.

2. Place the belt clip on top of the radio case back,

with the screw hole in the aligned with the hole in

the radio case.

3. Using the screw that came with this accessory,

attach the clip to the radio.

OPERATION SST-144

TROUBLESHOOTING

If you have trouble operating the handheld, review the

radio controls and operation sections. If you think the

radio is malfunctioning, check the following table.

GENERAL

The radio does not work at all.

• Make sure the battery is installed correctly, as

shown in FIG-1.

• Recharge or replace the battery. (See note 1.)

Operating features do not work exactly as expected.

• The radio has been factory or dealer

programmed for customized operation.

Reception is poor.

• Move to a different location. (Note 2.)

• Confirm that the proper antenna is connected to

the radio. (See p. 11, "Antenna.")

You cannot hear calls from other radios.

• Turn off tone squelch. (See Note 3.)

• Be certain your radio receives on the same as

the caller transmits. (Note 4.)

• Recharge the battery. (Note 1.)

Your calls cannot be heard in other radios.

• Make sure that your radio transmits on the

receive frequency of the radio(s) you want to call.

(Note 4.)

• Recharge the battery. (Note 1.)

TONE CODED SQUELCH

You cannot screen out calls from users outside of

your tone group.

• Make sure the channel is programmed with tone

squelch.

• Activate Tone (coded) squelch. (Note 7.)

You cannot hear Tone coded messages while in

Tone (coded) squelch.

• Confirm that the channel is programmed to

detect the same code as the calling radio(s)

transmits. (Note 7.)

Others in your tone group cannot hear your tone

coded messages.

• Verify that you transmit the same code as the

radio(s) you call are programmed to detect.

(Note 7.)

ERROR TONES

An error tone sounds when the radio is first

turned on.

• Replace the battery. (Note 1.)

• See "Error Tones" in the Operation section.

An error tone sounds while you are talking. (and

the transmitter shuts off).

• Refer to “Error Tones”

BATTERY

The battery loses its charge sooner than

expected.

• Review the battery charging instructions.

• Conserve the battery. (Note 5.)

• If the radio is used in extreme cold, warm the

radio under your coat. (Note 6.)

Notes

1. Try a battery pack from a working radio. If the radio in

question works with that pack, the original battery is

suspect. Charge the suspect battery as recommended

in this manual. Then, if the charged original battery

cannot power the handheld, try charging again with

another charger. If the battery still doesn’t hold a

charge, the pack should probably be replaced.

However, if the battery appears to be good after you try

the second charger, the first charger might be faulty. If

you think that an accessory is not operating properly,

contact your dealer or RITRON. (Radio accessories

come with a 90-day limited warranty.)

2. Reception can often be improved by moving a short

distance. This effect is more noticeable inside of

buildings. The range of these portables equipped with

a standard battery pack is about two miles (line-of-

sight).

3. If your radio does not detect calls from other radios on

the channel, turn off tone squelch. (Press both Volume

buttons at the same time - a double beep means that

tone squelch is off.)

4. If you want to hear a call, you must select a channel

that is programmed to receive the caller’s transmit

frequency. If you want to call another unit, you must

select a channel that is programmed to transmit the

other radio’s receive frequency. However, if you use a

repeater, your channel must be programmed to work

with the repeater’s transmit and receive frequencies.

(A radio channel can hold two separate operating

frequencies, one for Receive, the other for Transmit.)

5. Maximum power drain occurs while the radio transmits,

so don’t hold down the Push-To-Talk button more than

necessary. Battery power is used while the handheld is

left on to receive calls. If practical, switch off the unit.

6. In extreme cold, a battery’s charge capacity is greatly

reduced. If you use the radio in very cold weather,

periodically warm the portable underneath your coat if

possible. An optional remote speaker/microphone

would allow you to keep the radio under your coat while

transmitting and receiving.

7. In order for radios to communicate using Quiet Call,

they must be programmed with the same tone code.

Each code is unique, and your radio will respond only

to the code programmed. Press and hold both volume

buttons at the same time. A single beep means that

tone squelch is on. A double beep means that tone

squelch is off.

PROGRAMMING THE RADIO SST-144

PROGRAMMING METHODS

Each SST-144 can be programmed to operate on up

to 10 channels. The SST-144 may be programmed

using the Push-to-Talk switch or an optional RITRON

PC programming kit.

PTT (PUSH-TO-TALK) PROGRAMMING allows you

to program any channel to one of the radio

frequencies listed in Table 1 and any Quiet Call code

listed in Table 2. The radio will transmit and receive

on the programmed table frequency and QC code.

PC PROGRAMMING allows you to program any

frequency within the band and channel spacing of the

radio model. This method also lets you customize the

handheld with optional operating features.

PTT (PUSH-TO-TALK) PROGRAMMING

Note: If the radio will not enter PTT program

mode, this feature has probably been turned off

using the optional PC programming kit.

Reading Out a Radio Channel’s Contents

1. Place the radio in Program / Readout mode as

described in Fig-3.

2. Press the Channel Selector button to select the

radio channel you would like to read out.

3. Press and release the Volume Up button.

4. The radio will emit a series of beeps, pause, and

then begin another series. Four series of beeps

will be heard, with each series representing a

digit. The number of beeps in a series is equal

to the digit. (See CHANNEL READOUT)

5. Write down each digit while the radio pauses.

List the digits in the order that you hear them.

6. The first two digits represent the frequency as

shown in Frequency Table 1 on page 13.

7. The second two digits represent the QC

(CTCSS) tone frequency as shown in Quiet-Call

Tone Code Table 2 on page 13.

8. To read out another channel, follow steps 2

through 7.

9. Turn the radio off to exit Channel Readout mode.

Notes:

1. Ten (10) beeps = the digit zero (0)

2. The radio will beep out “44” as a tone code if it

has been programmed for “No Tone”.

3. A radio that has been PC-programmed with any

frequency not listed in Frequency Table 1, page

13, will emit the error tone on content readout.

Fig. 3 PLACING THE RADIO IN PTT

PROGRAM / READOUT MODE

CHANNEL READOUT:

FREQUENCY CODE

# of beeps

in series

1st

digit

∗

2nd

digit

∗

# of beeps

in series

TONE CODE

# of beeps

in series

3rd

digit

∗

4th

digit

♦

# of beeps

in series

Notes:

∗Pause after entering each digit. The radio

will emit a low tone, separating one digit

from the next.

♦ The radio sounds a triple beep when PTT

channel programming is complete.

PROGRAMMING THE RADIO SST-144

PTT Programming a Radio Channel

Four valid digits must be entered for the radio to

accept PTT programming. The first two digits entered

are the frequency code from Table 1, followed by the

two digits for the QC code from Table 2.

1. Place the radio in Program / Readout mode as

described in Fig-3 on page 11.

2. Press the Channel Selector button to select the

radio channel you would like to program.

3. Enter the first digit by pressing the PTT button

the number of times equal to the digit’s value.

4. Pause after the digit is entered, a low tone will

sound indicating that the digit has been

accepted.

5. Enter the second, third and fourth digits using the

same method as the first digit.

6. Press the Volume Up button to enter the new

channel programming. The radio will emit a triple

beep confirmation tone to indicate that

programming has been accepted.

7. To program another channel, follow steps 2

through 6.

8. Turn the radio off and then on again – the radio

is now ready for use.

Notes:

1. To enter the digit zero ( 0 ), press the PTT ten

times.

2. Program “44” to enter “No Code” for Quiet Call.

You must enter “44” to match radios not having

tone codes.

3. An error tone will sound if you attempt to save an

incorrect digit. Turn the radio off, check the

digits you are attempting to enter, then start over

again.

4. If you make a PTT click error, turn the radio off

then on, and start over.

5. If the radio does not emit a confirming triple tone

when you attempt to enter Program / Readout

mode, the radio was dealer customized to

disable PTT programming.

6. Refer to the Frequency Table 1 and Tone Code

(Quiet Call) Table 2 on page 13.

Return to Normal Operation

After you finish programming, turn the radio off and

then on again. The radio will beep when it is ready for

normal operation.

PTT Programming Mistakes

Invalid Entries An error tone means that

you tried to save an invalid entry. No programming

changes are made in this case. A triple tone will

sound next indicating that the radio is still in

programming mode, and ready for an entry.

PTT Entry Mistakes If you press the PTT five

times when you intended four, for example, or if you

just lose count, do not press the Volume Up button to

store the entry. Instead, start over by turning the

radio off and placing the radio in programming mode

again.

PTT CHANNEL PROGRAMMING:

FREQUENCY CODE

# of beeps

in series

1st

digit

∗

2nd

digit

∗

# of beeps

in series

TONE CODE

# of beeps

in series

3rd

digit

∗

4th

digit

♦

# of beeps

in series

Notes:

∗Pause after entering each digit. The radio

will emit a low tone, separating one digit from

the next.

♦ The radio sounds a triple beep when PTT

channel programming is complete.

PROGRAMMING THE RADIO SST-144

Code Frequency Description

01 154.600 Green Dot

02 154.570 Blue Dot

03 151.625 Red Dot

04 151.955 Purple Dot

05 151.925

06 154.540

07 154.515

08 154.655

09 151.685

10 151.715

11 151.775

12 151.805

Table 1 – PTT Programming Frequency Table

QC Freq QC Freq

Code (Hz) Code (Hz)

01 67.0 27 167.9

02 71.9 28 173.8

03 74.4 29 179.9

04 77.0 30 186.2

05 79.7 31 192.8

06 82.5 32 203.5

07 85.4 33 210.7

08 88.5 34 218.1

09 91.5 35 225.7

10 94.8 36 233.6

11 97.4 37 241.8

12 100.0 38 250.3

13 103.5 39 69.4

14 107.2 40 159.8

15 110.9 41 165.5

16 114.8 42 171.3

17 118.8 43 177.3

18 123.0 44 No Tone

19 127.3 45 183.5

20 131.8 46 189.9

21 136.5 47 196.6

22 141.3 48 199.5

23 146.2 49 206.5

24 151.4 50 229.1

25 156.7 51 254.1

26 162.2

Table 2 – Quiet Call Codes and Frequencies

COMPUTER SOFTWARE COPYRIGHTS

The RITRON, Inc. products described in this manual

include copyrighted RITRON, inc. computer

programs. Laws in the United States and other

countries grant to RITRON, inc. certain exclusive

rights in its copyrighted computer programs, including

the exclusive right to distribute copies of the

programs, make reproductions of the programs, and

prepare derivative works based on the programs.

Accordingly, any computer programs contained in

RITRON, inc. products may not be copied or

reproduced in any manner without the express written

permission of RITRON.

The purchase of RITRON, inc. products does not

grant any license or rights under the copyrights or

other intellectual property of RITRON, inc., except for

the non-exclusive, royalty fee license to use that

arises in the sale of a product, or as addressed in a

written agreement between RITRON, inc. and the

purchaser of RITRON, inc. products.

PC COMPUTER PROGRAMMING

RITRON’s programming kit allows programming of

the SST-144 model radios using a PC compatible

computer. An adapter cable connects the radio to a

computer’s serial communications port. Once the

cable is hooked up, the user inserts the diskette

provided into his computer’s floppy disk drive and

loads a software program.

This program transfers data between radio and

computer memory, and includes on-screen

instructions and help. Radio data may be saved to

the computer’s hard disk in order to program other

radios.

The PC Programming Kit Includes:

1) Ritron Transceiver programming software, which

is contained on 3.5" diskettes.

2) Installation instructions and a registration form.

3) Ritron PC to radio adapter cable, which is

terminated at one end with a DB-25F connector,

at the other end with a modular plug. The DB-25

plugs into the computer’s serial port, the modular

plug into the SST-SRVBD modular jack.

4) An adapter for use with SST-144 portables. This

adapter mates the modular plug to a 3.5 mm

plug, for connection to the handheld audio jack.

The PC Programming Kit Requires:

A PC compatible computer with Windows 95 or later.

The computer must have an RS-232 serial port and a

minimum of 2MB available on the hard disk drive for

installation.

PROGRAMMING THE RADIO SST-144

Programmable Features

The following features may be programmed on a per

channel basis, or will affect all channels together.

Feature RangeFactory Setting

Automatic Inactivity Y - N Y -

Turn-off

Battery Saver Enable Y - N Y -

Battery Saver Off Time 0 – 8 1 -

(seconds)

Beep Volume Level F-C C -

(Fixed or Controlled)

Beep Fixed Level 0 – 100% 50% -

(percent of full volume)

Busy Channel TX Inhibit Y - N N √

Carrier Only, No Codes - - √

Channel Beep Rate S – F S -

(Slow or Fast)

Channel Selection Mode I – E I -

(Increment or Enter)

Digital Tone Invert RX Y - N N √

Digital Tone Invert TX Y - N N √

Digital Quiet Call (DCS) - - √

Disable Monitor Y - N N √

Number of Channels 0 – 10 4 -

Narrow Band Channel Y - N N √

PTT Programming Y – N Y -

Enabled

Quiet Call (CTCSS) See Table 2 - √

Receive Squelch Tone Y - N N √

Squelch Tightener 0 - 7 0 √

Transmit Power L - H H √

(Low or High)

TX Time-out Enabled Y – N Y -

TX Time-out Timer 0 – 255 60 -

(seconds)

Turn On To Medium Y - N Y -

Volume Level

Descriptions of Features

Automatic Inactivity Turn-off - The radio automatically

shuts itself off if four hours go by without the micro-

controller detecting input from the volume, PTT or

channel controls.

Battery Saver - Enabling this option allows the radio

to go into battery saver mode when the radio remains

idle. The power saver begins after eight seconds of

inactivity.

Battery Saver Off Time - This is the cycle time that

the radio is off in battery saver mode before it checks

for a received signal. A long Battery Saver Off Time

may cause the user to miss the beginning of the first

message when in battery saver mode.

Beep Volume Level - The radio can be programmed

for a fixed beep volume or for a beep volume that is

adjusted with the Volume controls. If fixed beep

volume is selected, the fixed level can be set between

0 – 100%.

Busy Channel Transmit Inhibit - This keeps the radio

from broadcasting if the channel is busy, and is often

used in conjunction with Disable Monitor. If you press

the PTT when the channel is busy with a signal not

intended for your radio (not carrying your tone code),

this feature sounds a "busy" tone in the speaker and

keeps the transmitter turned off.

Channel Beep Rate - The rate at which the channel

indicator beeps occur can be set to fast or slow.

Channel Selection Mode - This feature allows the

channel selector to increment or enter the channel.

The channel number is "beeped out" when the

channel button is first pressed. The channel is not

changed. In increment mode the radio is changed to

the next available channel if the channel button is

pressed again within three seconds. In enter mode

the user must press the channel button the number of

times equal to the channel they wish to select.

Digital Quiet Call RX Invert - The programmed code

is inverted for receive mode only.

Digital Quiet Call TX Invert - The code is inverted for

transmit mode.

Disable Monitor - This function may be programmed

to keep the radio user from listening to other

licensees on a shared channel. QC or DQC must be

used for this option to have any affect, and the

Encode Only feature disabled.

Maximum Number of Channels - The number of

channels available on the radio can be set from 1 to

10.

Narrow Band Channel - Any channel can be set to

operate in narrow band mode, reducing the transmit

deviation to 2.5 KHz.

PTT Programming Mode Enabled - This feature

allows channel programming from a table of pre-

determined frequencies using the radio PTT switch.

PROGRAMMING THE RADIO SST-144

Quiet Call (CTCSS)- Programming a Quiet Call code

allows you to screen out transmissions that do not

carry your code. Your code is broadcast when you

press the PTT to make a call.

Quiet Call Encode Only - The Quiet Call code

programmed for the channel is transmitted with your

calls. However, no Quiet Call code is programmed

for receive mode, allowing all traffic on the channel to

be heard.

Receive Frequency - The radio frequency that

receives broadcasts from other units.

Receive Squelch Tone - The receiving radio beeps at

the end of each received transmission.

Squelch Tightener - This feature reduces distant "co-

channel" or other interference for channels that are

not programmed with Quiet Call. Carrier squelch is

set for maximum sensitivity at the factory, but may be

adjusted to mute weak signals

Transmit Frequency - The radio frequency that

broadcasts to other units.

Transmit Power – Any channel can be set to transmit

at high or low power.

Transmit Time Out Timer - This feature automatically

shuts off the transmitter (ending your call) if you hold

down the PTT button continuously for 60 seconds.

The radio sounds a tone when the transmitter shuts

off.

Turn On To Medium Volume Level - The volume level

is at mid-range when the radio is first turned on.

Normally, the volume level is low when the radio is

turned on.

THEORY OF OPERATION SST-144

INTRODUCTION

The SST-144 is a four-channel handheld transceiver

built on a single multi-layer printed circuit board. Both

sides of the main printed circuit board are populated

with components, with the bottom side containing

only surface mounted components.

The SST-144 is frequency synthesized, with all

functions of the radio controlled by microcontroller.

POWER SUPPLY AND VOLTAGE DISTRIBUTION

The SST-144 is powered by an internal 6-cell

rechargeable battery pack. The battery pack supplies

power to the radio via two contact terminals that are

connected to the PCB through P302. F301 is a 3A

fuse in series with P302 for short circuit protection.

The battery pack may be charged through 2.5 mm

charge jack J301 via CR302 and F301. Zener diode

CR301 prevents the batteries from discharging

through the charger accessory, stops a reverse

voltage from being applied to the battery pack

through J301, and prevents a high voltage from being

applied to the radio circuitry.

SW301 ON/VOL UP switch is pressed to turn on the

SST-144, turning on voltage pass transistor Q304 via

R302 and CR303. Q304 supplies power to IC309, a

+5 VDC regulator used to power microcontroller

IC301. Pin 13 of IC301 turns on Q303, which keeps

Q304 turned on after SW301 has been released.

Power is removed from the SST-144 by pressing the

VOL DN/OFF switch SW302 until a beep is heard

from the speaker, at which time Q304 is turned off.

+5 VDC regulator IC309 supplies power directly to

microcontroller IC301, bilateral audio gates IC304,

reference oscillator Y302, synthesizer IC401, and

PTT detect transistor Q302.

The T/R output at Pin 11 of IC301 lets Q101 switch

the regulated +5 VDC to the receiver. Pin 11 of

IC301 will also turn on Q202, which turns on voltage

pass transistor Q201. With Q201 emitter connected

to the +VBATT battery supply, the collector output is

connected to the emitter of Q202 through voltage

divider R202/R203, whose values are selected to limit

the TX+V voltage to +6 VDC.

Power Strobe

The SST-144 handheld includes a power strobe

feature, which reduces battery current drain by

periodically removing voltage from part of the radio.

The strobe off cycle time is programmable using the

PC Programming Kit. The +5V SW power strobe

output at Pin 10 of IC301 controls Q306, which

switches the regulated +5 VDC to the audio

processing circuitry and the synthesizer circuitry.

This includes IC303A 2.5 VDC (Vag) for bias on

audio processing circuitry, IC303C audio high pass

filter, IC308 and IC305A audio low pass filter for sub-

audible frequencies, IC305B audio limiting amplifier,

IC306 digital potentiometers, IC303B audio summing

node amplifier, and IC303D audio low pass filter.

Low Battery Voltage Detection

Battery voltage is measured at A/D input Pin 16 of

IC301 through voltage divider R303/R305. The radio

will emit a periodic beep if low battery voltage is

detected, and will turn the radio off if the battery

voltage drops below +5 VDC. This is to protect the

microcontroller and its EE memory from corruption

due to low supply voltage.

REFERENCE OSCILLATOR

Reference oscillator Y302 is a 1.5 ppm temperature

controlled, voltage controlled oscillator (TCVCXO)

operating at 14.4 MHz. The Pin 4 output of the

TCVCXO provides a reference for the frequency

synthesizer IC401 at Pin 20. IC401 is programmed to

provide an output at Pin 1 that is ¼ of the reference

(3.6 MHz), which is applied as a reference oscillator

to Pin 27 of IC301 microcontroller. The Y302 pin 4

output is also multiplied up to 43.2 MHz by Q105 and

its associated circuitry to provide a receiver 2nd local

oscillator signal.

SYNTHESIZER

The SST-144 radio is built around a common phase-

locked loop (PLL) that consists of a voltage-controlled

oscillator (VCO) and a frequency synthesizer. The

PLL generates both the receiver 1st local oscillator

and transmitter carrier signals. Control signals from

microcontroller IC301 and Reference oscillator Y302

are routed to frequency synthesizer IC401 per the

following chart:

Pin Numbers

IC301 Y302 IC401

Clock 12 - 18

Data 5 - 19

Latch 20 - 17

LD 12 - 2

T/R SW 11 - -

REF IN - 4 20

REF OUT 27 - 1

+5 SW 10 - 12

+5V 1, 15, 28 2 5, 14

Q404, CR401, C414 and associated components

provide a filtered supply for the VCO oscillator and

buffer amplifiers.

Prescaler Divider / Synthesizer Controller

IC401 contains both a prescaler and synthesizer

controller. The prescaler squares and divides the

VCO output present at pin 11 by either 64 or 65,

determined by a synthesizer controller logic signal.

The exact number of times the prescaler is instructed

THEORY OF OPERATION SST-144

to change divisors is determined by the channel

frequency.

IC401 contains a digital phase detector that works as

follows: when an operating channel is changed or the

receive/transmit mode switched, a new synthesizer

operating frequency is selected. Microcontroller

IC301 clocks new data into IC401 internal buffer in

synchronization with clock pulses. The channel

information is stored in EE memory of IC302 and is

loaded into RAM when the channel is selected.

Once new data is loaded into the buffer, a single

pulse from IC301 appears at IC401 to instruct the

synthesizer controller to latch and execute the new

data. IC401 utilizes internal circuitry to determine

whether the present VCO output frequency is correct

by comparing the phase and frequency of the VCO

signal at Pin 11 to the 14.4 MHz reference oscillator

at Pin 20. IC401 produces an output signal at Pin 6,

a single-ended phase/frequency detector output,

proportional to the phase difference between the two

input signals.

The loop filter C429, C427, R419, R420, R418, and

C426 transform the Pin 6 output signal to a DC

voltage for application to the VCO tuning varactor

CR402. The synthesizer system is “locked” when the

phase and frequency of both the reference and the

divided VCO signal are the same.

The maximum amount of current this output can sink

or source is determined by the value of R421 tied to

Pin 8 of IC401, with the output current programmable

to 25, 50 or 100% of maximum.

VCO / Buffer Amplifiers

Q403, L401, L406, CR402 and associated

components form the VCO (Voltage Controlled

Oscillator), a resonant circuit that oscillates at

frequencies from 150 MHz in transmit to 205 MHz in

receive (receive frequency + 43.65 MHz) to. Varying

the voltage at CR402 changes the varactor

capacitance, which in turn alters the VCO output

frequency.

When in receive mode a +5 VDC T/RSW signal is

applied to Q406, which turns on Q405 to draw current

through pin diode CR404 and L403. With CR404

biased on, L402 is effectively shorted to ground,

shifting the VCO frequency up 43.65 MHz.

Q401 and Q402 are buffer amplifiers, with Q401

feeding in the input of the synthesizer at Pin 11, the

receiver 1st local oscillator and the transmitter pre-

amplifier.

Oscillator Modulation

When the SST-144 is in transmit, modulation balance

control IC306E passes TX audio through to the VCO

modulation input at R416. TX audio is applied to

varactor CR403 to modulate the VCO. TX audio is

also routed to the Pin 1 input of TCVCXO reference

oscillator Y302. Low frequency tones modulate the

reference oscillator because the synthesizer is not

able to track them.

DIGITAL POTENTIOMETERS

IC306 contains 6 digital potentiometers programmed

by IC301, sharing the same clock and data outputs

used by the synthesizer and a separate Digital Pot

Latch signal from Pin 8. The digital potentiometers

are used in conjunction with IC303B, a summing

node amplifier used for modulating the VCO and

reference oscillator. IC306A, B, D, E, and F can only

be changed through serial programming, and can

only be performed by an authorized licensed RF

technician.

IC306A is connected through R352 to the Pin 6 input

of IC303B. IC306A adjusts the DC output of IC303B

to tune the reference oscillator frequency.

IC306B is connected to the Pin 2 Gate control of RF

power transistor Q203 to adjust transmitter power

output.

Volume control IC306C applies the processed voice

band signals at IC303D to audio amplifier IC307

when in receive mode. Depressing the ON/VOL UP

switch SW301 increases the setting of IC306C while

VOL DN/OFF switch SW302 decreases it.

Transmitter tone deviation control IC306D applies the

output of the selective signaling low-pass filter IC308

to the Pin 6 input of IC303B through R350. IC306D is

completely closed in receive mode.

Transmitter modulation balance control IC306E is

used to apply the Pin 7 output of IC303B to the VCO

modulation input. This will set the ratio of the

modulating signal applied to the VCO and the

reference oscillator. IC306E is completely closed in

receive mode.

Transmitter voice deviation control IC306F applies

the processed voice band signals at IC303D to the

Pin 6 input of IC303B through R349. IC306F is

completely closed in receive mode.

RECEIVER

As mentioned before, Q101 switches the regulated

+5 VDC to the receiver. The +VRX receiver voltage

is switched at the strobe duty cycle if programmed for

power strobe.

RF Amplifier

A received signal from the antenna passes through a

low-pass filter (L207, C218, C217, L208, C219, and

C222) to the receiver headend. L101, L103, and the

associated capacitors form a bandpass filter ahead of

low-noise RF amplifier Q102. The amplified RF

signal is applied to a 2-pole bandpass filter consisting

of L104, L105, and associated capacitors.

THEORY OF OPERATION SST-144

1st Mixer

The amplified received input signal is applied to the

gate of FET mixer Q103. The 1st local oscillator

signal from the synthesizer module is applied to the

source of Q103. L106, C117 and C118 tune the drain

output of Q103 to 43.65 MHz and apply it to YF101, a

43.65 MHz two-pole crystal filter. Q104 and

associated components amplify the 43.65 MHz IF

signal and apply it to the input of the 2nd mixer at Pin

16 of IC101.

FM Receiver Subsystem

A multi-function integrated circuit, IC101 and

associated components for the FM-receiver

subsystem. The subsystem performs the following

functions: 1) 2nd mixer, 2) 2nd IF amplifier, 3) FM

detector, and 4) noise amplifier.

The Pin 4 output of 14.4 MHz reference oscillator

Y302 is multiplied up to 43.2 MHz by Q105 and

associated components. This signal is applied to the

2nd local oscillator input at Pin 1 of IC101. The 43.65

MHz signal at Pin 16 and the 2nd local oscillator are

mixed, with the resulting 450 KHz output signal

appearing at Pin 3. This signal is filtered by a 450

KHz 6-pole ceramic filter YF102 and applied to the

input of the limiting IF amplifier at Pin 5. IC101 Pin 6

is the de-coupled input to the IF amplifier, Pin 7 the

limited IF output signal. An internal quadrature

detector, whose center frequency is determined by

450 KHz quadrature coil T101, detects the FM IF

signal. One input of the quadrature detector is

connected internally to the IF signal at Pin 7, while

the other input is the phase-shifted signal from T101

at Pin 8.

Demodulated audio appears at Pin 9, where a low-

pass filter (R114, C130) removes spurious quadrature

output prior to application to the voice/tone

conditioning audio circuitry. Demodulated audio from

Pin 9 is applied to the Pin 10 input of a noise

filter/amplifier consisting of R112, C123, C124, R110,

R111 and R113. The Pin 11 output of the noise

amplifier is applied to a biased noise detector CR103,

with the output connected to an A/D input of IC301 at

Pin 19. The SST-144 is serial programmed to set the

squelch threshold and hysteresis.

Voice / Tone Conditioning in Receive Mode

SST-144 audio conditioning filter circuits are shared

with the transmitter. The same high-pass

filter/amplifier (IC303C and associated components)

used in receive voice band conditioning is used in the

transmit band. Similarly, the low-pass filter (IC308

and associated components) used for selective signal

tone decode filtering is also used for selective signal

encoding. Altering circuit configuration with bilateral

switches IC304A, B and C permits the use of the

same audio filtering system for both transmit and

receive modes.

After R114 and C130 remove the 450 KHz element

from the demodulated audio output at Pin 9 of IC101,

C333 couples the audio signal to bilateral switch

IC304C for subaudible tone detection and connection

to IC304A for voice band audio processing.

Voice Band

Bilateral switch IC304A passes the received audio

signal to the input of IC303C, which along with its

associated components for a high-pass filter/amplifier

circuit that attenuates audio signals below 300 Hz.

The output of IC303C is applied to the input of

IC305B limiting amplifier. Bilateral switch IC304B is

switched in receive to insert C351 into the feedback

circuit of IC305B, providing de-emphasis of the

received audio signal. Bilateral switch IC304B also

removes R335 from the Pin 6 input to reduce the gain

and prevent limiting.

The output from IC305B is applied to the input of

IC303D, which along with its associated components

form an 18dB/octave low-pass filter for frequencies

above 3000 Hz.

The output of IC303D is connected to IC306C volume

control prior to connection to audio amplifier IC307.

The output of IC303D is also connected to IC306F

voice deviation control, which is completely closed in

receive mode to prevent received signals from

modulating the VCO and reference oscillators.

Audio frequency tones from Pin 24 of microcontroller

IC301 are applied to the Pin 6 input of IC305B to

provide the SST-144 alert tones.

Sub-Audible

Bilateral switch IC304C passes the received audio

signal to the input of IC305A, which amplifies the

signal and applies it to the Pin 2 input of IC308, a 5-

pole low-pass filter that attenuates frequencies above

250 Hz.

The output at Pin 5 is applied to an A/D input of

IC301 at Pin 18 for tone decoding. An internal digital

signal processing routine programmed into

microcontroller IC301 is used to decode the correct

selective signaling code. The output at Pin 5 of

IC308 is also connected to tone deviation control

IC306D, which is completely closed in receive mode

to prevent received subaudible tone signals from

modulating the VCO and reference oscillators.

Audio Amplifier

Receive audio from volume control IC306C is applied

to the Pin 2 input IC307, a 1 Watt audio amplifier.

C365 couples the Pin 5 output to the internal 8Ω

speaker SP301 via audio jack J303.

Microcontroller IC301 Pin 22 switches DC power to

the audio amplifier by turning on Q307, which then

turns on pass transistor Q308 to apply battery voltage

to Pin 6 of the audio amp. CR307 prevents an

inadvertent DC voltage at J303 from damaging the

audio amplifier.

THEORY OF OPERATION SST-144

ANTENNA SWITCHING / LOW PASS FILTER

A low-pass filter comprised of filter L208, C222,

C219, C218, C217, L207, and C220 removes

harmonics from the transmitter output before applying

the RF signal to the antenna. Received signals pass

through the low-pass filter before entering the

receiver RF amplifier circuitry.

Two PIN diodes (CR201, CR101) and associated

components form the antenna switching circuit. With

the SST-144 in receive mode, no voltage is applied to

the PIN diodes and they do not conduct. This reverse

biases CR201 to prevent the transmitter amplifier

from affecting the receiver tuning and removes

CR101 from the receiver input. Incoming signals

from the antenna pass through the low-pass filter,

then L206 and C101 to the receiver headend.

When the SST-144 is switched into transmit mode,

transmitter supply voltage is switched on by Q201

and Q202 and applied to R207. Current flows

through R207, L205, CR201, L206 and then CR101

to ground, forward biasing the PIN diodes. CR201

passes transmitter RF power to the antenna while

CR101 shunts the receiver RF amplifier input to

ground. L206 provides sufficient impedance to

isolate the transmitter power from the receiver RF

amplifier.

TRANSMITTER

Keying

The SST-144 transmitter is keyed when PTT switch

SW304 is depressed. Electret condenser

microphone M301 is connected in series to ground

with the PTT switch, which when depressed draws

current through M301, SW304, CR304 and R307 to

turn on pass transistor Q302. Q302 then turns on

Q301 to pull the TX Key Pin 2 input of microcontroller

IC301 low. The microcontroller T/R output at Pin 11

then goes high to turn on Q202, which turns on pass

transistor Q201 to apply +6VDC to the transmitter as

described previously. The transmitter can also be

keyed through J301 with an audio accessory that

inserts a microphone and PTT switch in series to

ground, drawing current through CR304.

+VTX Supply

With the transmitter enabled as described above, the

+VTX voltage from Q201 is applied to transmitter RF

amplifier Q204. +VTX supply also forward biases the

PIN switching diodes CR201 and CR101 as

previously described. The transmitter RF final

amplifier Q203 is powered by the battery supply.

The Pin 11 T/R output of microcontroller IC301 can

be PC programmed to hold the transmitter on after

the PTT switch has been released to allow tone

related turn-off codes for squelch tail elimination.

Power Amplifier

Q204 and associated components amplify the VCO

signal and apply it to the input of RF Final amplifier

module Q203 at Pin 1. The 50Ω output of Q203 is

matched to the antenna switching circuitry and

applied to the antenna through the low-pass filter.

The RF power output is programmable by a licensed

RF technician. The SST-144 can be programmed on

a channel-by-channel basis for low or high power

operation. The power control digital Potentiometer

IC306B is used to adjust the Q203 gate voltage and

set RF power output.

Voice / Tone Conditioning in Transmit Mode

SST-144 audio conditioning filter circuits are shared

with the receiver. The same high-pass filter/amplifier

(IC303C and associated components) used in receive

voice band conditioning is used in the transmitter

voice band. Similarly, the low-pass filter (IC308 and

associated components) used for sub-audible tone

decode filtering is also used for tone encode. Altering

circuit configuration with bilateral switches IC304A, B

and C permits the use of the same audio filtering

system for both transmit and receive modes.

Voice Band

M301 microphone audio is passes through CR304,

C334 and is switched by IC304A to the input of

IC303C, which along with its associated components

form a high-pass filter/amplifier circuit that attenuates

audio signals below 300 Hz. The output of IC303C is

applied to the input of IC305B limiting amplifier.

Bilateral switch IC304B switches R335 in parallel with

R336, raising the gain of limiting amplifier IC305B for

full limiting of the transmitter voice audio. The output

of IC305B is applied to the input of IC303D, which

along with its associated components form an 18

dB/octave low-pass filter for frequencies above 3

KHz. The output of IC303D is applied to voice

deviation control IC306F, which sets the level of the

processed transmitter audio applied to summing node

amplifier IC303B used to modulate the VCO and

reference oscillator.

Sub-Audible

Microcontroller IC301 generates the sub-audible

selective signaling encode waveforms at Pin 21 and

applies them to the input of buffer amplifier IC305A.

The output of IC305A is applied to the input of IC308,

a 5-pole low-pass filter that attenuates frequencies

above 250 Hz. C342 and C343 set the corner

frequency of the low-pass filter, with C342 switched in

by Pin 7 of IC301 to lower the corner frequency for

lower tones. The output of IC308 is applied to tone

deviation control IC306D, which sets the level of the

transmitter sub-audible encode tones applied to

summing node amplifier IC303B used to modulate

the VCO and reference oscillator.

THEORY OF OPERATION SST-144

MICROCONTROLLER

The SST-144 handheld transceiver is electronically

controlled by IC301, an 8-bit microcontroller. IC301

has four 8-bit A/D inputs for processing analog

signals.

PIN DESCRIPTION

1 RESET is connected to the SST-144 +5V to start

the radio in a known state on power up.

2 TX KEY input is pulled LOW when either the

internal or external PTT switch is pressed to

initiate transmitter operation.

3 AUDIO GATE ENABLE controls analog switches

IC304A and B to configure the shared audio

processing circuitry for receive operation when

LOW, and for transmitter operation when HIGH.

4 SERIAL DATA INPUT links the microcontroller to

communications from an external data terminal

via J303 RING connection. This allows

programming of the SST-144 EEPROM memory

used to store channel frequency and

configuration information.

5 DATA output sends serial data to frequency

synthesizer IC401 to program frequency

information, IC302 EEPROM memory, and to

IC306 to set the digital potentiometers.

6 EECLOCK output sends serial data clock pulses

to EEPROM IC302 when reading or writing.

7 LOW-PASS CUT-OFF output goes LOW to lower

the cut-off frequency of IC308 when the radio is

on a channel programmed for a CTCSS tone

below 150 Hz. This output is in a tri-state OPEN

condition for all other tones.

8 DIGITAL POT LATCH sends a single positive

pulse after data has been sent to IC306 to latch

the new data and change the digital

potentiometers to the new programmed settings.

9 LED output goes LOW when the radio is on

channel 1 and is HIGH for all other channels.

10 +5V SW output goes HIGH at a programmable

periodic rate to remove the +5VSW supply from

various circuits in the radio, thus conserving

battery life. In normal transmit or receive mode

this output is LOW.

11 T/R SWITCH output is connected to the

Synthesizer circuitry to shift the frequency of the

VCO oscillator used in both transmit and receive.

The output is HIGH in transmit and LOW in

receive. T/R output is also used to switch supply

voltage to the transmit and receive circuits.

12 CLOCK output sends serial data clock pulses to

frequency synthesizer IC401 and digital

potentiometers IC306 when programming these

devices.

13 +V SW output is HIGH when the radio is turned

on, keeping pass transistor Q304 turned on via

Q303 to supply power to the radio.

14 GROUND

15 VREFH sets the upper reference level for the A/D

and is connected to the regulated +5 VDC.

16 A/D input BATTERY is used to measure the

battery voltage for low and dead battery

detection. This input also serves as the ON/VOL

UP input, and is pulled LOW when SW301 is

depressed to turn on the radio and raise the

receiver speaker audio level.

17 A/D input VOL DN/OFF is pulled LOW when

SW302 is depressed to lower the receiver

speaker audio level and turn off the radio. This

input also serves as CHANNEL input, and goes

to 2.5 VDC when channel selector switch SW303

is pressed to change the radio to the next

programmed channel.

18 A/D input TONE DECODE accepts the received

QC (CTCSS) and DQC (DCS) waveforms after

signal processing for decode analysis.

19 A/D input RSSI is used to measure the output

voltage of the noise filter for squelch detection.

20 LATCH output goes LOW to allow serial data to

frequency synthesizer IC401 and goes HIGH to

latch the data, allowing the synthesizer to

execute the new frequency information.

21 TONE ENCODE outputs generate the QC

(CTCSS) and DQC (DCS) encode waveforms for

signal processing prior to modulating the VCO in

transmit mode.

22 AUDIO AMP ENABLE output goes HIGH to apply

power to audio amp IC307 for receiver speaker

audio or radio alert tones.

23 RX AUDIO GATE ENABLE switches IC304C for

receive operation when LOW, and for transmitter

operation when HIGH.

24 BEEP output generate the radio alert tones

heard in the speaker.

25 See Pin 4

27 REFERENCE OSCILLATOR INPUT has the 3.6

MHz reference signal from the synthesizer.

28 +5 VDC VDD supply voltage.

ALIGNMENT PROCEDURE SST-144

WARNING!

An authorized RF service technician must perform

test and alignment of the SST-144. Do not attempt

service of the SST-144 if not completely familiar

with the operation of frequency synthesized radio

operation. The SST-144 can operate in both

Narrow Band (2.5 KHz deviation) and Wide Band

(5 KHz deviation) systems.

RECOMMENDED TEST EQUIPMENT

1) 0 to +15 VDC, 2A current-limited power supply

2) RF Communications Test Set (to 162 MHz) with:

- FM Deviation Meter

- RF Wattmeter

- Frequency Counter (to 162 MHz)

- SINAD Measuring Device

3) Oscilloscope (to 20 MHz)

4) VTVM or DMM

5) RITRON PC Programming Kit

6) RITRON SST-SRVBD Test Module

RADIO PREPARATION

1) Make sure the radio battery is fully charged.

2) Install the RITRON SST-SRVBD test assembly

and serial programming cable as follows:

a) Remove the SST-144 antenna from the

radio.

b) Plug the SST-SRVBD into the 2.5 mm and

3.5 mm jacks on top of the radio.

c) Screw the SST-SRVBD antenna nut fully

into the SST-144 antenna connector.

d) Set the jumper on the SST-SRVBD

assembly to the “UHF” position.

e) Connect the serial programming cable from

the PC computer (with the RITRON PC

programming kit software installed) to the

SST-SRVBD test assembly

3) Connect the FM communications test set to the

BNC connector on the SST-SRVBD test

assembly.

4) Turn on the radio to place it in operating mode.

5) From the PC Programmer on-screen menu,

select “Tune Radio” to display the Alignment

screen.

6) Set the RF Communications Test set to the

Alignment Frequency indicated on the Alignment

screen.

7) Press the appropriate “Select” button on the

Alignment screen to make the following

adjustments:

SELECT Alignment

Frequency Transmit frequency

Mod Bal Modulation balance

Tone QC/DQC tone encode deviation

wide and narrow band

Voice Voice deviation with no tone

wide and narrow band

Voice deviation with tone

wide and narrow band

Power Low transmitter power

High transmitter power

8) After you have completed alignment of the SST-

144, turn the radio off. This will remove the test

frequencies and return to operation on the

customer’s programmed frequencies.

REFERENCE FREQUENCY

1) Make sure the unit has been switched on and is

at room temperature (approximately +25° C)

2) Select “Frequency” from the PC Programmer

“Alignment” screen.

3) Set the RF communications test set to the

Alignment Frequency on the Alignment screen.

4) Press the “Tune” button on the Alignment screen

to activate the transmitter.

5) Transmitter frequency error should be less than

+/- 500 Hz.

6) If frequency adjustment is required, press the left

arrow on the tuning bar to lower the frequency or

the right arrow to raise the frequency.

7) Press the “Save” button to store the new

alignment setting or “Cancel” to leave setting

unchanged.

ALIGNMENT PROCEDURE SST-144

MODULATION BALANCE

Transmitter modulation balance has been set at the

factory and should not require adjustment.

1) Select “Mod Bal” from the PC Programmer

“Alignment” screen.

2) Set the RF communications test set to the

Alignment Frequency on the Alignment screen.

3) Press the “Tune” button on the Alignment screen

to activate the transmitter.

4) Check the de-modulated waveform for a 20 Hz

square wave.

5) If adjustment of the modulation balance is

required, press the left arrow on the tuning bar to

flatten the top of the waveform or the right arrow

to reduce overshoot.

6) Press the “Save” button to store the new

alignment setting or “Cancel” to leave setting

unchanged.

TRANSMITTER TONE DEVIATION

Transmitter tone deviation has been set at the factory

and should not require adjustment.

1) Select “Tone” from the PC Programmer

“Alignment” screen.

2) Set the RF communications test set to the

transmit frequency on the screen.

3) Select either “Wide Band” or “Narrow Band” by

pressing the desired option button.

4) Press the “Tune” button on the Alignment screen

to activate the transmitter.

5) If adjustment of the tone deviation is required,

press the left arrow on the tuning bar to lower

deviation or the right arrow to raise deviation.

6) Press the “Save” button to store the new

alignment setting or “Cancel” to leave setting

unchanged.

TRANSMITTER VOICE DEVIATION

Transmitter voice deviation has been set at the

factory and should not require adjustment.

1) Select “Voice” from the PC Programmer

“Alignment” screen.

2) Set the RF communications test set to the

transmit frequency on the screen.

3) Select “Voice Only - Wide Band“, “Voice Only -

Narrow Band”, “Voice & Tone – Wide Band”, or

“Voice & Tone – Narrow Band” by pressing the

desired option button.

4) Press the “Tune” button on the Alignment screen

to activate the transmitter.

5) If adjustment of the voice deviation is required,

press the left arrow on the tuning bar to lower

deviation or the right arrow to raise deviation.

6) Press the “Save” button to store the new

alignment setting or “Cancel” to leave setting

unchanged.

TRANSMITTER POWER

Transmitter power has been set at the factory and

should not require adjustment.

1) Select “Power” from the PC Programmer

“Alignment” screen.

2) Set the RF communications test set to the

transmit frequency on the screen.

3) Select “Low Power” or “High Power” by pressing

the desired option button.

4) Press the “Tune” button on the Alignment screen

to activate the transmitter.

5) If adjustment of the transmitter power is required,

press the left arrow on the tuning bar to lower

power or the right arrow to raise power.

6) Press the “Save” button to store the new

alignment setting or “Cancel” to leave setting

unchanged.

ALIGNMENT PROCEDURE SST-144

RECEIVER SENSITIVITY AND SQUELCH

The SST-144 receiver is factory tuned for a frequency

range of 150 - 162 MHz. The SST-144 receiver is

configured from the factory for Wide Band operation,

with a Narrow Band Model available as an option.

The SST-144 receiver bandwidth is configured on a

per radio basis, it cannot be switched on a per

channel basis.

The receiver may be programmed to any frequency

between 150-162 MHz.

1) Program the radio to a receive frequency in the

middle of the 12 MHz band.

2) Set the RF Communications Test Set’s generator

to the programmed receive frequency at a RF

level of –120 dB. Modulate the RF signal with a 1

KHz tone at 3 KHz deviation for wide band, 1.5

KHz deviation for narrow band.

3) Check receiver sensitivity at the lowest and

highest operating frequencies and make slight

adjustment to L103 and L104 to balance

between the two, if necessary.

RECEIVER NOISE SQUELCH

The noise squelch sensitivity is set at the factory for a

12dB SINAD signal. Using the PC Programmer,

squelch sensitivity can be adjusted on a per channel

basis by adjusting the “Squelch Tightener” number to

between 0-7. The higher number will require a

stronger received signal to open squelch.

1) Select “Channel” from the PC Programmer “Edit”

menu on the main screen.

2) Select the channel to be set and press “Edit”

button.

3) Set the RF communications test set to the

transmit frequency on the screen.

4) Enter a Squelch Tightener number between 0-7.

5) Press the “OK” button on the Channel Edit

screen to return to the Channel List screen.

6) Select any other channels to be set.

7) Press the “OK” button on the Channel List screen

to return to the Main screen.

8) Select “Program Radio” from the PC

Programmer “Radio” menu to save all setting

changes.

SYNTHESIZER

The synthesizer is preset at the factory for operation

between 150 and 162 MHz. There is no manual

adjustment to center the control voltage, with all

adjustment performed by the factory selection of fixed

capacitor C413. Do not attempt to adjust the

synthesizer control unless a key component in the

synthesizer has been replaced. Key components do

not include the Y302 reference frequency TCVCXO or

IC401 synthesizer IC. Synthesizer alignment errors

cause poor operation at temperature extremes.

Should adjustment of the VCO control voltage be

necessary, the radio must first be disassembled and

powered up at 7.5 VDC. The following procedure

defines testing of the VCO control voltage:

1) Select the channel that has the lowest transmit

frequency.

2) Connect a VTVM, DVM or oscilloscope to Test

Point 1 and measure the VCO control voltage.

This voltage should be no less than 1.5 VDC.

3) Select the channel that has the highest receive

frequency and measure Test Point 1. The

control voltage should be no higher than 4.5

VDC.

4) a) If adjustment of the VCO control voltage is

required, remove the synthesizer shield top.

b) Squeeze or spread L401 or L406 that allows

VCO control voltages between 1.5 and 4.5

VDC for the operating frequencies desired.

Squeezing L401 or L406 will raise the

operating frequency of the VCO while

spreading L401 or L406 will lower the VCO

frequency.

c) Replace the top of the synthesizer shield.

VOLTAGE CHART SST-144

Measurement Conditions

Supply voltage at 7.5 VDC, radio in operating mode,

volume control at minimum, power strobe enabled,

transmitter set for full power.

IMPORTANT: Because the SST-144 portable is

constructed with grounding sub-planes, use a system

ground in the same proximity as the circuit being

measured. All readings indicated as GND are true

system ground.

KEY: All measurements are in VDC unless indicated

otherwise.

NC = No connection

GND = Ground

* = Voltage is strobed in

Power Saver mode

→= See note in right

column

REF PIN TX RX SB DESCRIPTION

CR101 1 0.9 0.0 0.0 TX/RX switching

2NCNCNC

3 GND GND GND

CR102 1 GND GND GND Voltage clamp

2 GND GND GND

30.00.0*

CR103 1 GND GND GND Noise detection

20.00.5*

30.00.2*

CR201 1 1.8 0.0 0.0 TX/RX switching

2NCNCNC

3 0.7 0.0 0.0

CR301 C 7.5 7.5 7.5 Over voltage protection

A GND GND GND

CR302 C 7.5 7.5 7.5 Reverse voltage

A 2.2 4.8 4.8 protection

CR303 1 6.8 6.8 6.8 Turn-on detection

2 3.8 3.8 3.8

3 6.5 6.5 6.5

CR304 1 3.9 4.7 4.7 PTT switching

2 2.5 4.7 4.7

3 3.0 5.0 5.0

CR305 1 GND GND GND Voltage clamp

2 5.0 5.0 5.0

3 0.0 0.0 0.0

CR306 1 2.4 2.4 2.4 Voltage clamp

2NCNCNC

3 2.4 2.4 2.4

CR307 C 7.5 7.5 7.5 Reverse volt protection

A0.0→*→ RX audio amp out

CR401 1 5.0 5.0 * Biasing

24.84.8*

3NCNCNC

REF PIN TX RX SB DESCRIPTION

CR402 1 GND GND GND VCO tuning

2NCNCNC

3→→ *→ 1.5 – 4.5 VDC

VCO tuning voltage

CR403 1 GND GND GND VCO modulation

2NCNCNC

32.42.4*

CR404 1 0.8 0.0 * TX/RX VCO switching

2NCNCNC

30.04.8*

IC101 1 0.0 4.7 * RX FM-IF subsystem

2NCNCNC

30.03.3*

40.04.7*

50.03.8*

60.03.8*

70.03.8*

80.04.7*

90.01.9*

10 0.0 0.6 *

11 0.0 1.6 *

12 0.0 0.0 *

13 NC NC NC

14 NC NC NC

15 GND GND GND

16 0.0 1.4 *

IC301 1 5.0 5.0 5.0 Microcontroller

20.05.05.0

35.00.00.0

40.00.00.0

50.00.00.0

60.00.00.0

70.00.00.0

80.00.00.0

9→→→ → 0.0 V on Channel 1

10 0.0 0.0 * else 5.0 VDC

11 5.0 0.0 0.0

12 5.0 5.0 *

13 5.0 5.0 5.0

14 GND GND GND

15 5.0 5.0 5.0

16 3.8 3.8 3.8

17 5.0 5.0 5.0

18 2.4 2.4 *

19 0.0 0.5 *

20 5.0 5.0 5.0

21 →2.4 * → 0-5 VDC tone

22 0.0 5.0 0.0 encode waveform

23 0.0 0.0 0.0

24 NC NC NC

25 0.0 0.0 0.0

26 NC NC NC

27 →→→ → 3.6 MHz clock signal

28 5.0 5.0 5.0

IC302 1 GND GND GND EEPROM

2 GND GND GND

3 GND GND GND

4 GND GND GND

50.00.00.0

60.00.00.0

7 GND GND GND

85.05.05.0

SOT-23

VOLTAGE CHART SST-144

REF PIN TX RX SB DESCRIPTION

IC303 1 2.4 2.4 * Audio processing

22.42.4*

32.42.4*

45.05.0*

52.42.4*

62.42.4*

72.42.4*

82.42.4*

92.42.4*

10 2.4 2.4 *

11 GND GND GND

12 2.4 2.4 *

13 2.4 2.4 *

14 2.4 2.4 *

IC304 1 0.0 0.0 * Audio signal switching

22.42.4*

32.42.4*

42.42.4*

50.02.5*

6 GND GND GND

7 GND GND GND

8 GND GND GND

9 5.0 0.0 0.0

10 5.0 0.0 0.0

11 5.0 0.0 0.0

12 2.4 2.4 *

13 NC NC NC

14 0.0 2.4 *

15 0.0 2.4 *

16 5.0 5.0 5.0

IC305 1 2.4 2.4 * Audio processing

22.42.4*

32.42.4*

4 GND GND GND

52.42.4*

62.42.4*

72.42.4*

85.05.0*

IC306 1 2.0 2.0 * Audio signal level

2 3.8 0.0 * control

3 GND GND GND

40.02.5*

52.42.4*

62.42.4*

72.42.4*

80.00.0*

95.05.0*

10 GND GND GND

11 NC NC NC

12 0.0 0.0 *

13 2.4 2.4 *

14 2.4 2.4 *

15 2.4 2.4 *

16 2.4 2.4 *

17 2.4 2.4 *

18 4.0 4.0 *

19 5.0 5.0 *

20 5.0 5.0 *

IC307 1 NC 1.2 0.5 Audio amplifier

2 0.0 0.0 0.0

3 GND GND GND

4 GND GND GND

5 0.0 3.7 0.0

6 0.0 7.5 0.0

7 0.0 3.7 0.4

8 NC 1.2 0.4

REF PIN TX RX SB DESCRIPTION

IC308 1 2.4 2.4 * Tone low pass filter

22.42.4*

3 GND GND GND

45.05.0*

52.42.4*

62.42.4*

75.05.0*

83.23.2*

IC309 1 7.5 7.5 7.5 +5 VDC voltage

2 GND GND GND regulator

3 7.5 7.5 7.5

4NCNCNC

55.05.05.0

IC401 1 →→→ → 3.6 MHz clock signal

2 5.0 5.0 * Frequency synthesizer

3NCNCNC

4NCNCNC

55.05.05.0

6→→ *→ 1.5 – 4.5 VDC VCO

7 GND GND GND tuning voltage

82.22.2*

9NCNCNC

10 2.4 2.4 *

11 2.4 2.4 *

12 5.0 5.0 *

13 NC NC NC

14 5.0 5.0 5.0

15 0.0 0.0 *

16 NC NC NC

17 5.0 5.0 5.0

18 5.0 5.0 *

19 0.0 0.0 *

20 2.2 →2.2 →*→ 14.4 MHz reference

Q 101 1 5.0 4.3 * RX +V switching

25.05.0*

30.04.7*

Q 102 1 0.0 0.7 * RX RF amplifier

2 GND GND GND

30.03.5*

Q 103 1 0.0 4.8 * RX mixer

20.01.4*

30.00.0*

Q 104 1 0.0 0.7 * RX IF amplifier

2 GND GND GND

30.04.0*

Q 105 1 0.0 0.4 * RX 2nd LO

2 GND GND GND multiplier/amp

30.04.0*

Q 201 1 6.8 7.5 7.5 TX +V switching

27.57.57.5

36.00.00.0

Q 202 1 5.0 0.0 0.0 TX +V switching

24.30.00.0

36.87.57.5

Q 203 1 0.0 0.0 0.0 TX RF final amplifier

22.80.00.0

37.57.57.5

40.00.00.0

5 GND GND GND

VOLTAGE CHART SST-144

REF PIN TX RX SB DESCRIPTION

Q 204 1 0.5 0.0 0.0 TX RF driver amplifier

2 0.0 0.0 0.0

3 5.3 0.0 0.0

Q 301 1 5.0 0.0 0.0 PTT detection

2 GND GND GND

3 0.0 5.0 5.0

Q 302 1 4.3 5.0 5.0 PTT detection

2 5.0 5.0 5.0

3 5.0 0.0 0.0

Q 303 1 5.0 5.0 5.0 Battery +V switching

2 4.3 4.3 4.3

3 6.8 6.8 6.8

Q 304 1 6.8 6.8 6.8 Battery +V switching

2 7.5 7.5 7.5

3 7.5 7.5 7.5

Q 306 1 4.3 4.3 5.0 +5V switching

2 5.0 5.0 5.0

35.05.0*

Q 307 1 0.0 5.0 0.0 Audio amplifier enable

2 0.0 4.3 0.0

3 7.5 6.8 7.5

Q 308 1 7.5 6.8 7.5 Audio amplifier +V

2 7.5 7.5 7.5 switching

3 0.0 7.5 0.0

Q 401 1 0.7 0.7 * VCO buffer amplifier

2 GND GND GND

32.42.4*

Q 402 1 0.7 0.7 * VCO buffer amplifier

2 GND GND GND

32.62.6*

Q 403 1 1.6 1.6 * VCO oscillator

21.01.0*

34.04.0*

Q 404 1 4.7 4.7 * VCO voltage

2 4.0 4.0 * de-coupling

35.05.0*

Q 405 1 4.0 0.0 * TX/RX VCO switching

24.04.0*

30.04.0*

Q 406 1 5.0 0.0 * TX/RX VCO switching

2 GND GND GND

30.02.3*

4 4.0 0.0 *

5 0.0 2.3

SCHEMATIC REFERENCE PARTS LIST SST-144

NOTE: This parts list reflects the most current component values. If a component value given in the schematic

differs from this list, the parts list should be considered the most current.

Last Update: May 18, 2001

Ref Ritron PN Description X Y Theta Loc

CAPACITORS

C101 15110470 47PF NPO 0805 50V CHIP 1164 3624 270 Top

C102 15110820 82PF NPO 0805 50V CHIP CAPACITOR 899 3667 180 Top

C103 15110151 150PF NPO 0805 50V CHIP 792 3627 270 Top

C104 15110470 47PF NPO 0805 50V CHIP 792 3762 90 Top

C105 15110470 47PF NPO 0805 50V CHIP 716 4125 180 Top

C106 15110330 33PF NPO 0805 50V CHIP 756 4235 90 Top

C108 15181102 .001uF CAPACITOR, CHIP, 0402, X7R, 5/10% 502 4166 180 Top

C109 15110680 68PF NPO 0805 50V CHIP CAPACITOR 525 4371 180 Top

C110 15110330 33PF NPO 0805 50V CHIP 525 4275 0 Top

C112 15110330 33PF NPO 0805 50V CHIP 373 4112 270 Top

C113 15110101 100PF NPO 0805 50V CHIP CAP 265 4152 180 Top

C115 151101A0 1.0PF NPO 0805 50V CHIP 308 3679 0 Top

C116 15182103 .01uF CAPACITOR, CHIP, 0402,Z5U,5/10/20 473 3415 270 Top

C117 15110150 15PF 0805 NPO 50V CHIP CAP 308 3599 180 Top

C118 15110470 47PF NPO 0805 50V CHIP 199 3558 90 Top

C119 15111472 .0047MF X7R 0805 50V CHIP 647 3594 270 Top

C120 151108A2 8.2PF NPO 0805 50V CHIP 407 3548 0 Bottom

C121 15181102 .001uF CAPACITOR, CHIP, 0402, X7R, 5/10% 138 947 90 Bottom

C122 152B6106 10uF 10V 3.4 X 2.8 CHIP TANTALUM 451 1669 0 Bottom

C123 15181102 .001uF CAPACITOR, CHIP, 0402, X7R, 5/10% 450 946 90 Bottom

C124 15181102 .001uF CAPACITOR, CHIP, 0402, X7R, 5/10% 320 904 90 Bottom

C125 15119104 .1uF X7R 0805 25V CERAMIC CHIP CAP 350 1364 0 Bottom

C126 15119104 .1uF X7R 0805 25V CERAMIC CHIP CAP 441 1557 0 Bottom

C127 15119104 .1uF X7R 0805 25V CERAMIC CHIP CAP 63 2202 0 Bottom

C128 15119104 .1uF X7R 0805 25V CERAMIC CHIP CAP 220 2114 270 Bottom

C129 15119104 .1uF X7R 0805 25V CERAMIC CHIP CAP 392 1802 0 Bottom

C130 15182103 .01uF CAPACITOR, CHIP, 0402,Z5U,5/10/20 571 904 90 Bottom

C131 15110330 33PF NPO 0805 50V CHIP 38 1263 0 Bottom

C132 15110330 33PF NPO 0805 50V CHIP 64 1156 270 Bottom

C133 15119104 .1uF X7R 0805 25V CERAMIC CHIP CAP 62 2119 0 Bottom

C134 15182103 .01uF CAPACITOR, CHIP, 0402,Z5U,5/10/20 39 1635 90 Top

C135 15110220 22PF NPO 0805 50V CHIP CAP 171 1533 180 Bottom

C201 15180101 100pF CAPACITOR, CHIP, 0402, COG, 5% 1308 3154 90 Bottom

C202 15181102 .001uF CAPACITOR, CHIP, 0402, X7R, 5/10% 839 3384 270 Bottom

C203 15180101 100pF CAPACITOR, CHIP, 0402, COG, 5% 997 3248 90 Bottom

C204 152A8105 1MFD 16V ~3.2 X 1.6~ CHIP TANTALUM 959 3458 270 Bottom

C205 15181102 .001uF CAPACITOR, CHIP, 0402, X7R, 5/10% 879 3425 90 Bottom

C206 15180101 100pF CAPACITOR, CHIP, 0402, COG, 5% 1748 3308 90 Bottom

C207 15181102 .001uF CAPACITOR, CHIP, 0402, X7R, 5/10% 1748 3104 90 Bottom

C208 15111102 .001MF X7R 0805 50V CHIP CAP 1741 2324 0 Top

C209 15119104 .1uF X7R 0805 25V CERAMIC CHIP CAP 1427 2284 90 Bottom

C210 15180101 100pF CAPACITOR, CHIP, 0402, COG, 5% 1492 2264 90 Bottom

C212 15110150 15PF 0805 NPO 50V CHIP CAP 1741 2244 0 Top

C215 15110330 33PF NPO 0805 50V CHIP 1495 4105 180 Top

C217 15110150 15PF 0805 NPO 50V CHIP CAP 1387 4085 90 Top

C218 151103A9 3.9PF NPO 0805 50V CHIP 1149 3942 180 Top

C219 15110330 33PF NPO 0805 50V CHIP 1014 3942 180 Top

C220 151104A7 4.7PF NPO 0805 50V CHIP 1013 4177 180 Top

C221 15111102 .001MF X7R 0805 50V CHIP CAP 973 4413 90 Top

C222 15110220 22PF NPO 0805 50V CHIP CAP 933 4296 180 Top

C301 15181102 .001uF CAPACITOR, CHIP, 0402, X7R, 5/10% 774 817 180 Bottom

C302 15181102 .001uF CAPACITOR, CHIP, 0402, X7R, 5/10% 271 522 270 Top

C303 152B4226 22uF 6.3V 3.4 X 2.8 CHIP TANTALUM CAP 199 647 180 Top

C304 15181102 .001uF CAPACITOR, CHIP, 0402, X7R, 5/10% 1261 4590 90 Bottom

C305 15180101 100pF CAPACITOR, CHIP, 0402, COG, 5% 1027 384 0 Top

C306 15180101 100pF CAPACITOR, CHIP, 0402, COG, 5% 563 398 270 Top

C307 15182103 .01uF CAPACITOR, CHIP, 0402,Z5U,5/10/20 20 4621 270 Top

SCHEMATIC REFERENCE PARTS LIST SST-144

Ref Ritron PN Description X Y Theta Loc

C308 15111102 .001MF X7R 0805 50V CHIP CAP 0 0 0 Bottom

C309 15182103 .01uF CAPACITOR, CHIP, 0402,Z5U,5/10/20 496 1867 90 Bottom

C310 15119104 .1uF X7R 0805 25V CERAMIC CHIP CAP 1107 3264 0 Bottom

C311 15181102 .001uF CAPACITOR, CHIP, 0402, X7R, 5/10% 1229 2967 90 Bottom

C312 15182103 .01uF CAPACITOR, CHIP, 0402,Z5U,5/10/20 501 4622 270 Top

C313 15181102 .001uF CAPACITOR, CHIP, 0402, X7R, 5/10% 169 3033 270 Top

C314 15181102 .001uF CAPACITOR, CHIP, 0402, X7R, 5/10% 1280 2595 180 Bottom

C315 15181102 .001uF CAPACITOR, CHIP, 0402, X7R, 5/10% 1280 2271 180 Bottom

C316 15182103 .01uF CAPACITOR, CHIP, 0402,Z5U,5/10/20 826 2291 180 Top

C317 15181102 .001uF CAPACITOR, CHIP, 0402, X7R, 5/10% 704 2321 0 Bottom

C318 15181102 .001uF CAPACITOR, CHIP, 0402, X7R, 5/10% 826 2371 180 Top

C319 15181102 .001uF CAPACITOR, CHIP, 0402, X7R, 5/10% 704 2360 0 Bottom

C320 15181102 .001uF CAPACITOR, CHIP, 0402, X7R, 5/10% 1280 2402 180 Bottom

C321 15181102 .001uF CAPACITOR, CHIP, 0402, X7R, 5/10% 1280 2503 180 Bottom

C322 15180101 100pF CAPACITOR, CHIP, 0402, COG, 5% 1280 2311 180 Bottom

C323 15181102 .001uF CAPACITOR, CHIP, 0402, X7R, 5/10% 1280 2771 180 Bottom

C324 15119104 .1uF X7R 0805 25V CERAMIC CHIP CAP 969 2221 0 Top

C325 15180101 100pF CAPACITOR, CHIP, 0402, COG, 5% 1280 2673 180 Bottom

C326 15180101 100pF CAPACITOR, CHIP, 0402, COG, 5% 1280 2634 180 Bottom

C327 15181102 .001uF CAPACITOR, CHIP, 0402, X7R, 5/10% 1280 2350 180 Bottom

C328 15181102 .001uF CAPACITOR, CHIP, 0402, X7R, 5/10% 658 2429 0 Bottom

C329 15181102 .001uF CAPACITOR, CHIP, 0402, X7R, 5/10% 638 2501 270 Bottom

C330 15181102 .001uF CAPACITOR, CHIP, 0402, X7R, 5/10% 704 2613 0 Bottom

C331 15181102 .001uF CAPACITOR, CHIP, 0402, X7R, 5/10% 705 2692 0 Bottom

C332 15181102 .001uF CAPACITOR, CHIP, 0402, X7R, 5/10% 705 2731 0 Bottom

C333 152A6475 4.7UF 10V A-SIZE TANTALUM CHIP CAP 502 2703 180 Top

C334 15119104 .1uF X7R 0805 25V CERAMIC CHIP CAP 91 2749 180 Bottom

C335 15180101 100pF CAPACITOR, CHIP, 0402, COG, 5% 331 2879 270 Bottom

C336 15181332 .0033uF CAPACITOR, CHIP, 0402, X7R,5/10% 454 3156 90 Bottom

C337 152B6106 10uF 10V 3.4 X 2.8 CHIP TANTALUM 702 3457 270 Bottom

C338 15180101 100pF CAPACITOR, CHIP, 0402, COG, 5% 254 3129 90 Top

C339 15119104 .1uF X7R 0805 25V CERAMIC CHIP CAP 245 2945 270 Top

C340 15111333 .033MFD X7R 0805 50V CHIP CAP 339 2675 270 Bottom

C341 15182103 .01uF CAPACITOR, CHIP, 0402,Z5U,5/10/20 585 2328 270 Bottom

C342 15110821 820PF NPO 0805 50V CHIP CAP 635 2984 180 Bottom

C343 15181102 .001uF CAPACITOR, CHIP, 0402, X7R, 5/10% 649 3064 180 Bottom

C344 15181472 .0047uF CAPACITOR, CHIP, 0402, X7R,5/10% 174 2439 0 Top

C345 15181472 .0047uF CAPACITOR, CHIP, 0402, X7R,5/10% 269 2431 0 Top

C346 152A8105 1MFD 16V ~3.2 X 1.6~ CHIP TANTALUM 614 2247 90 Top

C347 15180180 18pF CAPACITOR, CHIP, 0402, COG, 5% 286 2500 90 Top

C348 15119473 .047uF X7R 0805 25V CHIP CAPACITOR 469 2595 0 Top

C349 15111333 .033MFD X7R 0805 50V CHIP CAP 81 2641 90 Bottom

C350 15180101 100pF CAPACITOR, CHIP, 0402, COG, 5% 493 3156 90 Bottom

C351 15181222 .0022uF CAPACITOR, CHIP, 0402, X7R,5/10% 20 2640 270 Top

C352 15180100 10pF CAPACITOR, CHIP, 0402, COG, 5% 433 3234 90 Top

C353 15182103 .01uF CAPACITOR, CHIP, 0402,Z5U,5/10/20 594 3168 180 Bottom

C354 15181221 220pF CAPACITOR, CHIP, 0402, X7R, 5/10% 379 2436 90 Bottom

C355 15181102 .001uF CAPACITOR, CHIP, 0402, X7R, 5/10% 251 2415 180 Bottom

C356 15181102 .001uF CAPACITOR, CHIP, 0402, X7R, 5/10% 189 2436 90 Bottom

C357 15181102 .001uF CAPACITOR, CHIP, 0402, X7R, 5/10% 126 2415 0 Bottom

C358 15181102 .001uF CAPACITOR, CHIP, 0402, X7R, 5/10% 585 2498 90 Bottom

C359 15180100 10pF CAPACITOR, CHIP, 0402, COG, 5% 471 2588 270 Bottom

C360 15181102 .001uF CAPACITOR, CHIP, 0402, X7R, 5/10% 465 2277 270 Top

C361 15180101 100pF CAPACITOR, CHIP, 0402, COG, 5% 459 2138 90 Bottom

C362 15119104 .1uF X7R 0805 25V CERAMIC CHIP CAP 981 752 270 Bottom

C363 152B6106 10uF 10V 3.4 X 2.8 CHIP TANTALUM 1231 427 0 Top

C365 01503212 220MF 10V ELT CAPACITOR, 5mm HEIGHT 1489 5432 0.302 Top

C366 15119104 .1uF X7R 0805 25V CERAMIC CHIP CAP 1508 709 180 Bottom

C367 15119104 .1uF X7R 0805 25V CERAMIC CHIP CAP 1357 798 90 Bottom

C368 15181102 .001uF CAPACITOR, CHIP, 0402, X7R, 5/10% 231 2696 270 Bottom

C369 15180101 100pF CAPACITOR, CHIP, 0402, COG, 5% 663 2469 90 Top

C370 15181102 .001uF CAPACITOR, CHIP, 0402, X7R, 5/10% 293 2856 180 Top

C371 15181102 .001uF CAPACITOR, CHIP, 0402, X7R, 5/10% 704 2652 180 Bottom

C372 15181102 .001uF CAPACITOR, CHIP, 0402, X7R, 5/10% 560 2588 90 Bottom

SCHEMATIC REFERENCE PARTS LIST SST-144

Ref Ritron PN Description X Y Theta Loc

C373 15119104 .1uF X7R 0805 25V CERAMIC CHIP CAP 359 2320 90 Bottom

C384 152B6106 10uF 10V 3.4 X 2.8 CHIP TANTALUM 1062 455 90 Bottom

C401 15180101 100pF CAPACITOR, CHIP, 0402, COG, 5% 1566 1966 270 Top

C402 15110101 100PF NPO 0805 50V CHIP CAP 1638 1931 90 Top

C403 15181102 .001uF CAPACITOR, CHIP, 0402, X7R, 5/10% 1741 1871 90 Top

C404 15180101 100pF CAPACITOR, CHIP, 0402, COG, 5% 1066 1850 180 Top

C405 15181102 .001uF CAPACITOR, CHIP, 0402, X7R, 5/10% 1353 2013 180 Top

C406 15110101 100PF NPO 0805 50V CHIP CAP 1182 1785 270 Top

C409 15119104 .1uF X7R 0805 25V CERAMIC CHIP CAP 980 1766 90 Top

C410 15110100 10PF NPO 0805 50V CHIP CAP 1295 1589 270 Top

C411 15111102 .001MF X7R 0805 50V CHIP CAP 1375 1285 270 Top

C412 15181102 .001uF CAPACITOR, CHIP, 0402, X7R, 5/10% 1047 1788 90 Top

C413 151105A6 5.6PF NPO 0805 50V CHIP CAPACITOR 1463 1101 90 Top

C414 152B6106 10uF 10V 3.4 X 2.8 CHIP TANTALUM 722 1625 0 Top

C415 15181102 .001uF CAPACITOR, CHIP, 0402, X7R, 5/10% 1695 947 270 Top

C416 15180101 100pF CAPACITOR, CHIP, 0402, COG, 5% 1715 1341 180 Top

C417 15181102 .001uF CAPACITOR, CHIP, 0402, X7R, 5/10% 1717 1145 0 Top

C418 15180101 100pF CAPACITOR, CHIP, 0402, COG, 5% 677 1121 180 Top

C419 15181102 .001uF CAPACITOR, CHIP, 0402, X7R, 5/10% 678 1214 180 Top

C420 15181102 .001uF CAPACITOR, CHIP, 0402, X7R, 5/10% 678 1254 180 Top

C421 15180101 100pF CAPACITOR, CHIP, 0402, COG, 5% 1053 1601 180 Top

C423 151101A0 1.0PF NPO 0805 50V CHIP 1255 1482 0 Top

C424 151105A6 5.6PF NPO 0805 50V CHIP CAPACITOR 1295 1337 90 Top

C425 15180101 100pF CAPACITOR, CHIP, 0402, COG, 5% 1069 937 90 Top

C426 15111103 .01MF X7R 0805 50V CHIP 832 922 180 Top

C427 152AB224 0.22uF 35V 3.2 X 1.6 CHIP TANATULUM CAP 817 1015 0 Top

C428 15181102 .001uF CAPACITOR, CHIP, 0402, X7R, 5/10% 855 1473 270 Top

C429 15111223 .022mf X7R 0805 CHIP CAP 50V 1029 1028 0 Top

C430 15180101 100pF CAPACITOR, CHIP, 0402, COG, 5% 971 1460 270 Top

C431 15110100 10PF NPO 0805 50V CHIP CAP 774 1486 270 Top

C432 15180101 100pF CAPACITOR, CHIP, 0402, COG, 5% 766 1100 180 Top

C433 15180101 100pF CAPACITOR, CHIP, 0402, COG, 5% 932 1460 90 Top

C434 15180101 100pF CAPACITOR, CHIP, 0402, COG, 5% 1081 1183 270 Top

C435 15180101 100pF CAPACITOR, CHIP, 0402, COG, 5% 687 1355 180 Top

C436 15180101 100pF CAPACITOR, CHIP, 0402, COG, 5% 1429 1703 90 Top

DIODE

CR101 48D100A2 MA4CP101A PIN DIODE, SOT-23 1052 3624 90 Top

CR102 48E1005G MMBD-352LT1 SCHOTTKY DIODE SOT23 852 4125 0 Top

CR103 48A1005C MMBD7000, DUAL DIODES IN SERIES, SOT-23 366 2121 0 Bottom

CR201 48D100A2 MA4CP101A PIN DIODE, SOT-23 1467 3990 0 Top

CR301 48B61012 1N4742A ZENER DIODE, 12V 1W DL-41 MELF 991 604 90 Top

CR302 48AA01SA DIODE, 1A, 50V, SMT, D0214AC CASE 1154 630 90 Top

CR303 48A1005B MMBD6100, DUAL DIODES, COM CATHODE, SOT2 363 431 90 Top

CR304 48A100A3 MMBD2835, DUAL DIODES, COM ANODE, SOT-23 65 4114 0 Top

CR305 48A1005C MMBD7000, DUAL DIODES IN SERIES, SOT-23 617 2823 0 Bottom

CR306 48A1005C MMBD7000, DUAL DIODES IN SERIES, SOT-23 449 2956 90 Bottom

CR307 48AA01SA DIODE, 1A, 50V, SMT, D0214AC CASE 1290 630 90 Top

CR401 48A1005C MMBD7000, DUAL DIODES IN SERIES, SOT-23 695 1808 90 Top

CR402 48C10AQ3 VARACTOR DIODE, SMV1236-004, SOT-23 1186 1339 0 Top

CR403 48C1004G MMBV-2101L DIODE VVC SOT-23 1118 1482 180 Top

CR404 48A1004D MMBV3401 PIN/UHF DIODE SOT-23 1599 1102 270 Top

FUSE

F301 06000040 WIRE; #40AWG TINNED BUS (INCHES) 754 603 270 Bottom

INTEGRATED CIRCUITS

IC101 31030003 MC3371D SUBSYSTEM IC, SO-16 314 1158 270 Bottom

IC301 314G0306 MCU, 28 PIN, SOIC, SST/JMX 4 SERIES v06 992 2546 0 Bottom

IC302 31210005 EEPROM, 512X8, 24C04 989 2501 180 Top

IC303 310K0004 LMV324MT RAIL TO RAIL QUAD OP AMP 474 2442 180 Top

IC304 311K0003 SWITCH,ANALOG,TRIPLE SPDT,4053,TSSOP-16 228 2684 0 Top

IC305 310K0003 LMV358MM DUAL OP AMP, GP LV R/R TSSOP 404 3120 0 Top

SCHEMATIC REFERENCE PARTS LIST SST-144

Ref Ritron PN Description X Y Theta Loc

IC306 310K0001 DS1806E 6 PROG POTS 10K OHM 20-PIN TSSOP 242 2185 0 Top

IC307 31010004 LM386MX-1 AUDIO AMP SO-8 1331 567 90 Bottom

IC308 310K0002 MAX7410 5TH ORDER SW CAP BUTTERWORTH LPF403 2935 0 Top

IC309 310E0002 REGULATOR,LDO,LP2980,5V,W ENABLE,SOT-25 162 504 0 Top

IC401 313K0005 SYNTHESIZER, MC145193, TSSOP 891 1265 180 Top

JACKS

J301 02100001 2.5MM PC-MT JACK; ANT-CHGR 1178 4668 0 Top

J303 02100053 3.5MM STEREO JACK; PANEL MOUNT 1560 4646 0 Top

INDUCTORS

L101 01870954 4.5T AIRFCW COIL .09 a L= 43 nH 1090 3757 125 Top

L103 01870954 4.5T AIRFCW COIL .09 a L= 43 nH 792 38829 0.145 Top

L104 01870955 5.5T AIRFCW COIL .1 a L = 51 nH 413 4371 180 Top

L105 01870954 4.5T AIRFCW COIL .09 a L= 43 nH 268 4044 270 Top

L106 18110102 CHIP INDUCTOR 1.0uhy 381 3481 270 Top

L107 18110220 INDUCTOR, CHIP, 22nH 593 3729 0 Top

L108 18110681 CHIP INDUCTOR .68uhy 51 1648 180 Bottom

L202 18110102 CHIP INDUCTOR 1.0uhy 1454 2281 180 Top

L204 18433108 8T AIRCOIL, SMT, 28.0NH, .120 X .270 1695 3988 90 Top

L205 18110102 CHIP INDUCTOR 1.0uhy 1509 3851 0 Top

L206 01870955 5.5T AIRFCW COIL .1 a L = 51 nH 1163 3757 0 Top

L207 01870954 4.5T AIRFCW COIL .09 a L= 43 nH 1321 39435 0.113 Top

L208 01870954 4.5T AIRFCW COIL .09 a L= 43 nH 1109 40278 0.746 Top

L401 18433107 7T AIRCOIL, SMT, 22.0NH, .120 X .270 1516 1486 0 Top

L402 18433110 10T AIRCOIL, SMT, 43.0NH, .120 X .270 1349 1062 270 Top

L403 18110102 CHIP INDUCTOR 1.0uhy 1590 968 0 Top

L404 18110331 CHIP INDUCTOR .33uhy 1187 964 180 Top

L406 18433104 4T AIRCOIL SMT 12.5nH .120 X .145 1601 1756 90 Top

MICROPHONE

M301 05500037 MICROPHONE; ELECTRET, MINIATURE 0 0 0 Bottom

PLUGS

P201 25500700 CONTACT, PCB MNT, ANTENNA,SST 896 4550 90 Top

P302 21310021 HEADER, 2 PIN SIDE ENTRY SHROUDED 754 737 0 Top

TRANSISTORS

Q101 4801002A MMBT3906 PNP, SOT23 565 4072 270 Top

Q102 48210E2P BFS17A, VHF, SOT-23 LOW NOISE 661 4371 0 Top

Q103 4841006U MMBFJ309LT1, N-CHAN, RF, SOT23 373 3843 270 Top

Q104 4821003B MMBT918LT1 VHF SOT23 (3B) 270 3548 0 Bottom

Q105 4821003B MMBT918LT1 VHF SOT23 (3B) 38 1374 180 Bottom

Q201 4801002A MMBT3906 PNP, SOT23 908 3268 90 Bottom

Q202 4801001Q MMBT5088, NPN, SOT-23 766 3268 270 Bottom

Q203 04801505 M68776 7W RF MODULE 135-175 MHZ 7.2V 1819 2710 90 Top

Q204 4821007A MMBR901LT1 1GHZ SOT-23 (7A) 1603 2274 270 Top

Q301 48010R02 MUN2211T1, NPN, INT 10K/10K BIAS, "8A", 1133 2987 90 Bottom

Q302 4801002A MMBT3906 PNP, SOT23 1094 3124 90 Bottom

Q303 4801001Q MMBT5088, NPN, SOT-23 583 519 0 Top

Q304 480100DH BCW68GLT1 .8AMP PNP SOT-23 445 668 0 Top

Q306 480100DH BCW68GLT1 .8AMP PNP SOT-23 1222 2259 90 Top

Q307 4801001Q MMBT5088, NPN, SOT-23 964 615 0 Bottom

Q308 480100DH BCW68GLT1 .8AMP PNP SOT-23 1152 679 0 Bottom

Q401 4821007A MMBR901LT1 1GHZ SOT-23 (7A) 1470 1919 270 Top

Q402 4821007A MMBR901LT1 1GHZ SOT-23 (7A) 1289 1920 270 Top

Q403 4821007A MMBR901LT1 1GHZ SOT-23 (7A) 1333 1724 270 Top

Q404 4801001Q MMBT5088, NPN, SOT-23 837 1766 270 Top

Q405 4801006A MUN2111T1, PNP, INT 10K/10K BIAS, SC-59 1556 1241 0 Top

Q406 480A0002 TRANSISTOR, DUAL NPN W/10K UMG9N SOT23-5 1710 1242 270 Top

SCHEMATIC REFERENCE PARTS LIST SST-144

Ref Ritron PN Description X Y Theta Loc

RESISTORS

R101 47180103 10K OHM, RESISTOR, CHIP, 0402,1/16W,5% 527 3955 90 Top

R102 47180472 4.7K OHM RESISTOR, CHIP, 0402, 1/16W, 5% 175 3530 270 Bottom

R103 47180332 3.3K OHM RESISTOR, CHIP, 0402, 1/16W, 5% 645 4275 180 Top

R104 47180102 1K OHM RESISTOR, CHIP,0402, 1/16W,5% 756 4355 270 Top

R105 47180271 270 OHM RESISTOR, CHIP, 0402, 1/16W, 5% 565 4187 270 Top

R106 47180152 1.5K OHM RESISTOR, CHIP, 0402, 1/16W,5% 469 3824 270 Top

R107 47180152 1.5K OHM RESISTOR, CHIP, 0402, 1/16W,5% 388 3484 180 Bottom

R108 47180223 22K OHM RESISTOR, CHIP, 0402, 1/16W, 5% 251 3450 180 Bottom

R109 47180101 100 OHM RESISTOR, CHIP, 0402,1/16W,5% 167 3450 180 Bottom

R110 47180154 150K OHM RESISTOR, CHIP, 0402, 1/16W,5% 411 946 270 Bottom

R111 47180122 1.2K OHM RESISTOR, CHIP, 0402, 1/16W,5% 529 904 270 Bottom

R112 47180224 220K OHM RESISTOR, CHIP, 0402, 1/16W, 5% 349 966 180 Bottom

R113 47180123 12K OHM RESISTOR, CHIP, 0402, 1/16W,5% 489 946 90 Bottom

R114 47180152 1.5K OHM RESISTOR, CHIP, 0402, 1/16W,5% 551 966 0 Bottom

R115 47180104 100K OHM, RESISTOR, CHIP, 0402,1/16W,5% 155 2174 270 Bottom

R116 47180103 10K OHM, RESISTOR, CHIP, 0402,1/16W,5% 155 2089 90 Bottom

R117 47180393 39K OHM RESISTOR, CHIP, 0402, 1/16W, 5% 117 1676 90 Top

R118 47180103 10K OHM, RESISTOR, CHIP, 0402,1/16W,5% 49 1486 90 Bottom

R119 47180102 1K OHM RESISTOR, CHIP,0402, 1/16W,5% 9 1486 270 Bottom

R120 47180681 680 OHM RESISTOR, CHIP, 0402, 1/16W, 5% 78 1635 90 Top

R201 47180103 10K OHM, RESISTOR, CHIP, 0402,1/16W,5% 800 3384 90 Bottom

R202 47180471 470 OHM RESISTOR, CHIP, 0402, 1/6W, 5% 669 3248 270 Bottom

R203 47180121 120 OHM, RESISTOR, CHIP, 0402, 1/16W,5% 908 3151 90 Bottom

R205 47180822 8.2K OHM RESISTOR, CHIP, 0402, 1/16W, 5% 1555 2244 0 Bottom

R206 47180182 1.8K OHM RESISTOR, CHIP, 0402, 1/16W,5% 1618 2264 270 Bottom

R207 47180181 180 OHM RESISTOR, CHIP, 0402, 1/16W, 5% 1384 3842 180 Top

R208 47180102 1K OHM RESISTOR, CHIP,0402, 1/16W,5% 899 4425 90 Top

R301 47180103 10K OHM, RESISTOR, CHIP, 0402,1/16W,5% 536 686 90 Top

R302 47100471 470 OHM 0805 CHIP RES. 475 479 270 Top

R303 47180104 100K OHM, RESISTOR, CHIP, 0402,1/16W,5% 316 546 90 Top

R304 47180102 1K OHM RESISTOR, CHIP,0402, 1/16W,5% 623 639 270 Top

R305 47180104 100K OHM, RESISTOR, CHIP, 0402,1/16W,5% 410 547 270 Top

R306 47180103 10K OHM, RESISTOR, CHIP, 0402,1/16W,5% 535 1867 90 Bottom

R307 47180103 10K OHM, RESISTOR, CHIP, 0402,1/16W,5% 998 3143 90 Bottom

R308 47180103 10K OHM, RESISTOR, CHIP, 0402,1/16W,5% 1127 3328 180 Bottom

R309 47180103 10K OHM, RESISTOR, CHIP, 0402,1/16W,5% 1257 2891 270 Bottom

R310 47180104 100K OHM, RESISTOR, CHIP, 0402,1/16W,5% 704 2191 0 Bottom

R311 47180104 100K OHM, RESISTOR, CHIP, 0402,1/16W,5% 461 4622 270 Top

R312 47180103 10K OHM, RESISTOR, CHIP, 0402,1/16W,5% 704 2230 0 Bottom

R313 47180104 100K OHM, RESISTOR, CHIP, 0402,1/16W,5% 1184 2376 270 Top

R314 47180472 4.7K OHM RESISTOR, CHIP, 0402, 1/16W, 5% 1260 2375 270 Top

R315 47180102 1K OHM RESISTOR, CHIP,0402, 1/16W,5% 738 2841 90 Bottom

R316 47180103 10K OHM, RESISTOR, CHIP, 0402,1/16W,5% 760 2506 90 Top

R317 47180103 10K OHM, RESISTOR, CHIP, 0402,1/16W,5% 799 2506 90 Top

R318 47180104 100K OHM, RESISTOR, CHIP, 0402,1/16W,5% 704 2521 180 Bottom

R319 47180471 470 OHM RESISTOR, CHIP, 0402, 1/6W, 5% 705 2770 180 Bottom

R320 47180471 470 OHM RESISTOR, CHIP, 0402, 1/6W, 5% 643 2919 0 Bottom

R321 47180103 10K OHM, RESISTOR, CHIP, 0402,1/16W,5% 752 2957 180 Bottom

R322 47180393 39K OHM RESISTOR, CHIP, 0402, 1/16W, 5% 294 3070 270 Bottom

R323 47180823 82K OHM RESISTOR, CHIP, 0402, 1/16W, 5% 371 3070 270 Bottom

R324 47180224 220K OHM RESISTOR, CHIP, 0402, 1/16W, 5% 332 3070 270 Bottom

R325 47180104 100K OHM, RESISTOR, CHIP, 0402,1/16W,5% 416 3156 90 Bottom

R326 47180183 18K OHM RESISTOR, CHIP, 0402, 1/16W, 5% 585 2413 270 Bottom

R327 47180183 18K OHM RESISTOR, CHIP, 0402, 1/16W, 5% 624 2328 90 Bottom

R328 47180103 10K OHM, RESISTOR, CHIP, 0402,1/16W,5% 479 2791 270 Bottom

R329 47180153 15K OHM RESISTOR, CHIP, 0402, 1/16W,5% 174 2400 180 Top

R330 47180100 10 OHM RESISTOR, CHIP,0402, 1/16W 5% 664 2384 90 Top

R331 47180104 100K OHM, RESISTOR, CHIP, 0402,1/16W,5% 269 2391 0 Top

R332 47180154 150K OHM RESISTOR, CHIP, 0402, 1/16W,5% 207 2501 90 Top

R333 47180473 47K OHM RESISTOR, CHIP, 0402, 1/16W, 5% 246 2500 90 Top

R334 47180273 27K OHM RESISTOR, CHIP, 0402, 1/16W, 5% 561 2588 90 Top

R335 47180102 1K OHM RESISTOR, CHIP,0402, 1/16W,5% 39 2787 270 Top

SCHEMATIC REFERENCE PARTS LIST SST-144

Ref Ritron PN Description X Y Theta Loc

R336 47180104 100K OHM, RESISTOR, CHIP, 0402,1/16W,5% 2 2787 270 Top

R337 47180103 10K OHM, RESISTOR, CHIP, 0402,1/16W,5% 532 3156 270 Bottom

R338 47180224 220K OHM RESISTOR, CHIP, 0402, 1/16W, 5% 393 3234 90 Top

R339 47180394 390K OHM RESISTOR, CHIP, 0402, 1/6W, 5% 467 2361 270 Bottom

R340 47180104 100K OHM, RESISTOR, CHIP, 0402,1/16W,5% 340 2436 90 Bottom

R341 47180104 100K OHM, RESISTOR, CHIP, 0402,1/16W,5% 251 2456 0 Bottom

R342 47180184 180K OHM RESISTOR, CHIP, 0402, 1/16W, 5% 65 2394 270 Bottom

R343 47180564 560K OHM RESISTOR, CHIP, 0402, 1/16W, 5% 696 3167 0 Top

R344 47180104 100K OHM, RESISTOR, CHIP, 0402,1/16W,5% 26 2424 270 Bottom

R345 47180104 100K OHM, RESISTOR, CHIP, 0402,1/16W,5% 127 2456 180 Bottom

R346 47180102 1K OHM RESISTOR, CHIP,0402, 1/16W,5% 697 3129 180 Bottom

R347 47180100 10 OHM RESISTOR, CHIP,0402, 1/16W 5% 517 2650 180 Bottom

R348 47180473 47K OHM RESISTOR, CHIP, 0402, 1/16W, 5% 432 2588 270 Bottom

R349 47180473 47K OHM RESISTOR, CHIP, 0402, 1/16W, 5% 29 2146 0 Top

R350 47180224 220K OHM RESISTOR, CHIP, 0402, 1/16W, 5% 29 2198 0 Top

R351 47180222 2.2K OHM RESISTOR, CHIP, 0402, 1/16W, 5% 426 2277 90 Top

R352 47100225 2.2M 0805 CHIP RESISTOR 50 2410 0 Top

R353 47180103 10K OHM, RESISTOR, CHIP, 0402,1/16W,5% 483 2162 180 Top

R354 47180102 1K OHM RESISTOR, CHIP,0402, 1/16W,5% 847 653 180 Bottom

R355 47180103 10K OHM, RESISTOR, CHIP, 0402,1/16W,5% 912 772 90 Bottom

R356 47180273 27K OHM RESISTOR, CHIP, 0402, 1/16W, 5% 1172 775 0 Bottom

R357 47180102 1K OHM RESISTOR, CHIP,0402, 1/16W,5% 1178 534 270 Bottom

R358 47180103 10K OHM, RESISTOR, CHIP, 0402,1/16W,5% 251 2376 0 Bottom

R359 47180100 10 OHM RESISTOR, CHIP,0402, 1/16W 5% 1600 730 270 Bottom

R360 Factory Select 139 588 90 Bottom

R361 Factory Select 188 588 90 Bottom

R401 47180101 100 OHM RESISTOR, CHIP, 0402,1/16W,5% 1517 2006 90 Top

R402 47180221 220 OHM RESISTOR, CHIP, 0402, 1/16W, 5% 1702 1871 270 Top

R403 47180272 2.7K OHM RESISTOR, CHIP, 0402, 1/16W, 5% 1450 2013 180 Top

R404 47180102 1K OHM RESISTOR, CHIP,0402, 1/16W,5% 1429 1802 90 Top

R405 47180471 470 OHM RESISTOR, CHIP, 0402, 1/6W, 5% 1153 1900 270 Top

R406 47180272 2.7K OHM RESISTOR, CHIP, 0402, 1/16W, 5% 1193 1900 270 Top

R407 47180470 47 OHM RESISTOR, CHIP, 0402, 1/16W, 5% 1086 1788 270 Top

R408 47180470 47 OHM RESISTOR, CHIP, 0402, 1/16W, 5% 1067 1726 180 Top

R409 47180100 10 OHM RESISTOR, CHIP,0402, 1/16W 5% 1390 1631 180 Top

R410 47180153 15K OHM RESISTOR, CHIP, 0402, 1/16W,5% 1206 1633 180 Top

R411 47180103 10K OHM, RESISTOR, CHIP, 0402,1/16W,5% 1206 1684 0 Top

R412 47180102 1K OHM RESISTOR, CHIP,0402, 1/16W,5% 1271 1827 180 Top

R413 47180472 4.7K OHM RESISTOR, CHIP, 0402, 1/16W, 5% 677 1903 0 Top

R414 47180103 10K OHM, RESISTOR, CHIP, 0402,1/16W,5% 1464 1311 270 Top

R415 47180102 1K OHM RESISTOR, CHIP,0402, 1/16W,5% 1695 1032 90 Top

R416 47180104 100K OHM, RESISTOR, CHIP, 0402,1/16W,5% 1138 1601 0 Top

R417 47180102 1K OHM RESISTOR, CHIP,0402, 1/16W,5% 924 933 90 Top

R418 47180103 10K OHM, RESISTOR, CHIP, 0402,1/16W,5% 936 1028 90 Top

R419 47180123 12K OHM RESISTOR, CHIP, 0402, 1/16W,5% 718 906 0 Top

R420 47180103 10K OHM, RESISTOR, CHIP, 0402,1/16W,5% 718 946 180 Top

R421 47180392 3.9K OHM RESISTOR, CHIP, 0402, 1/16W, 5% 1081 1325 90 Top

R422 47180100 10 OHM RESISTOR, CHIP,0402, 1/16W 5% 894 1461 90 Top

R423 47180474 470K OHM RESISTOR, 0402, 1/16W, 5% 850 1100 180 Top

R424 47180681 680 OHM RESISTOR, CHIP, 0402, 1/16W, 5% 1468 1703 90 Top

R425 47180103 10K OHM, RESISTOR, CHIP, 0402,1/16W,5% 1617 1337 180 Top

SPEAKER

SP301 05500045 SPEAKER, 45MM, 1W, LOW PROFILE SST/RTX 0 0 0 Bottom

SWITCHES

SW301 05100042 SWITCH SPST MOMENTARY MINI PC 260GM 268 4587 180 Top

SW302 05100042 SWITCH SPST MOMENTARY MINI PC 260GM 788 4588 180 Top

SW303 05100046 SWITCH, TACT LO PROFILE RT ANGLE 160gf 82 3097 270 Top

SW304 05100046 SWITCH, TACT LO PROFILE RT ANGLE 160gf 82 3948 270 Top

SCHEMATIC REFERENCE PARTS LIST SST-144

Ref Ritron PN Description X Y Theta Loc

TRANSFORMER

T101 05600018 455KHZ IF TRANSFORMER (5MM) 128 1822 180 Top

CRYSTAL

Y302 23050003 TCVCXO, 14.400 MHz, 1.5 PPM, VC=30 PPM/V 146 837 90 Top

FILTERS

YF101 02301403 43.650 MHz Crystal Filter +/-6.0KHz UM-1 44 3524 90 Top

YF102 02301013 FILTER,CERAMIC,450KHz,+/-7.5KHz,6 POLE 249 1614 90 Top

HARDWARE

1750250A PCB, ML4 FR4 5UPM, .062 MIX, SST-144

25602500 CRYSTAL SUPPORT, RUBBER PAD, SMALL/UM-1

06001010 #24 AWG STRANDED WIRE; RED (INCHES)

06001011 #24 AWG STRANDED WIRE; BLACK INCHES

06001023 #28 AWG STRANDED WIRE;GREEN INCHES

06001029 #28 AWG STRANDED WIRE; BLUE INCHES

25105500 SHIELD, SST-PLUS SYNTHESIZER

25603000 FOAM, MOUNTING, SPEAKER,SST

25603900 SPACER, MIC FOAM, SST

25605700 MICROPHONE HOLDER, SST-PLUS

ANTENNA

AFS-150 ANTENNA VHF MOLDED, 150-160 REG LEN SST

MAIN CASE ASSEMBLY

13250000 CASE W/INSERT, PLASTIC, SST BLACK

13578000 DOOR, BATTERY, PLASTIC, SST 2-PC

13588000 LATCH, BATTERY DOOR, PLASTIC SST 2-PC

25106400 BATTERY DOOR HINGE RETAINER

25201500 RETAINER, PLASTIC, PTT, SST

25400600 BUSHING, THREADED, PLATED, ANTENNA SS

25603300 GRILLE CLOTH, SPEAKER, SST

25603400 DUAL JACK PLUG, RUBBER,SST

25606200 HINGE, BATTERY DOOR, SST

25800500 ACTUATOR, RUBBER,PTT,SST

25800600 ACTUATOR, RUBBER, TACT, SST

02802026 NUT; KNURLED; M4PO.5;/2.5MM JACK

02802027 NUT; KNURLED; M6PO.5/3.5MM JACK

28112401 SCREW 4-40 X 1/4" PHFLST

28233G03 KNURLED NUT, ANTENNA, JMX

CASE BOTTOM ASSEMBLY

13564000 CASE, BOTTOM, PLASTIC, SST 2-PC

2142D021 CONNECTOR, CABLE ASSEMBLY, 2-POS, SST+

25400800 SPRING CONTACT, BATTERY, SST W/O TABSC

25400900 CONTACT BATTERY SST-PLUS (POLARIZED)

25604800 SPACER, PCB, FOAM, SST 2-PC

BELT CLIP

25201600 BELT CLIP, PLASTIC, SST BLACK

2811B600 SCREW 6-32 X 1/4" PHTRST

SCHEMATIC REFERENCE PARTS LIST SST-144

Ritron PN Description

SST-144 MODELS ONLY

CASE LABELS

14220001 LABEL, CONTROLS, SST

14222029 LABEL, NAMEPLATE, SST

14290002 BLANK LABEL, .75" X .25" GLOSSY WHITE

14200037 LABEL SST/JMX MFG DATE CODE

14200104 LABEL, FCC SERIAL, SST-144

BATTERY PACK AND INSULATOR

BPS-6N-SC BATTERY,RECHG,7.2V NiCd,BLUE ,SST

14230088 LABEL, BATTERY, BPS-6N-SC, SST

25300600 INSULATOR, BATTERY, FIBRE, SST

25606000 FOAM SUPPORT, BATTERY JMX SERIES

25601600 BATTERY SHIM; ASSEMBLY ~X~ SERIES

PACKING MATERIALS

14210004 LOW BATTERY NOTICE LABEL

14312006 SHIPPING CARTON, CARDBOARD,SST

14321002 FOAM INSERT, PACKING, SST/MINI

14500025 OWNER'S MANUAL, 14x/44x SERIES, JMX/SST

14540006 WARRANTY REGISTRATION CARD

JMX-144 MODELS ONLY

CASE LABELS

14220002 LABEL, CONTROLS, JMX

14222035 LABEL, NAMEPLATE, JMX

14290002 BLANK LABEL, .75" X .25" GLOSSY WHITE

14200037 LABEL SST/JMX MFG DATE CODE

14200103 LABEL, FCC SERIAL, JMX-144

BATTERY PACK AND INSULATOR

BPJS-6N BATTERY, YELLOW, RECHG,7.2V NiCd 700 mAH

BC-A BATTERY CHARGER, 120VAC-5.5VDC 100mA

14230088 LABEL, BATTERY, BPS-6N-SC, SST

25300600 INSULATOR, BATTERY, FIBRE, SST

25606000 FOAM SUPPORT, BATTERY JMX SERIES

25601600 BATTERY SHIM; ASSEMBLY ~X~ SERIES

PACKING MATERIALS

14210004 LOW BATTERY NOTICE LABEL

14313012 BOX, CHIPBOARD, SMALL, 4 COLOR, JMX

14352004 INSERT, CORREGATED CARDBOARD, JMX

14500025 OWNER'S MANUAL, 14x/44x SERIES, JMX/SST

14540006 WARRANTY REGISTRATION CARD

14610006 JOBCOM BROCHURE

Ritron RIT13-144 Handheld FM Transceiver User Manual 144 manC

Ritron Inc Handheld FM Transceiver 144 manC

User Manual

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