Ritron RIT13-450 UHF-FM Handheld Radio Transceiver User Manual SST 454 THEORY OF OPERATION

Ritron Inc UHF-FM Handheld Radio Transceiver SST 454 THEORY OF OPERATION

Maintenance manual

TYPE OF EXHIBIT: INSTRUCTION MANUALSFCC PART: 2.1033 (c)(3)MANUFACTURER: RITRON, INC.505 West Carmel DriveCarmel, IN 46032MODEL: SST-444TYPE OF UNIT: UHF-FM Handheld TransceiverFCC ID: AIERIT13-450DATE: July 7, 2000Included in this exhibit is a draft of the Maintenance and Operating Manual for RITRON Model PatriotSST-444 UHF-FM Handheld Transceiver.Specifically, this manual includes a technical description of the SST-444 sufficient to establish compliancewith 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 circuitsused to suppress spurious radiation, limiting modulation, and limiting power.(12) Drawing with labels for controls and complete circuit diagrams.Signed: Michael A. Pickard - Project Engineer
2TABLE OF CONTENTSSECTION TOPIC PAGE1. SST-444 SPECIFICATIONSGENERAL 4RECEIVER 5TRANSMITTER 62. INTRODUCTIONGENERAL 7Inspection 7Model Identification 7FCC REGULATIONSLicensing 7Safety Standards 73. BATTERY CARECHARGING 8BATTERY REPLACEMENT 9PRECAUTIONS 94. DESCRIPTION OF CONTROLS AND CONNECTORS 10Fig. 2 Controls and Connectors 11Belt Clip Installation 115. OPERATIONOn-Off/Volume 12Receive 12Monitor 12Selective Signaling Squelch 12Battery Saver 12Transmit 13Channel Selection 13WHAT THE RADIO TONES MEANPower On/Self Check “OK 13Error Tones 13Channel Select 13Tone Squelch 13Recharge Battery Alert 13OPTIONAL RADIO TONESReceiver Squelch Tone 14Busy Channel Inhibit 14Transmitter Time Out 14TROUBLESHOOTINGGeneral 15Battery 15Error Tones 15Tone Coded Squelch 166. PROGRAMMING THE RADIOPTT (PUSH-TO-TALK) PROGRAMMINGPlacing the Radio in PTT Programming Mode 17How To Find Out What Is Already Programmed 17PTT Programming the Radio 18PTT Programming Mistakes 18Return To Normal Operation 18Table 1 – PTT Programming Frequency Table 19
3Table 2 – Quiet Call Codes and Frequencies 19COMPUTER SOFTWARE COPYRIGHTS 19PROGRAMMING THE RADIO USING A PC COMPUTER 20Programmable Features 20Description of Features 217. SST-444 THEORY OF OPERATIONINTRODUCTION 22POWER SUPPLY AND VOLTAGE DISTRIBUTION 22Power Strobe 22Low Battery Voltage Detection 22REFERENCE OSCILLATOR 23SYNTHESIZER 23Pin Numbers 23Prescaler Divider / Synthesizer Controller 23VCO / Buffer Amplifiers 24Oscillator Modulation 24DIGITAL POTENTIOMETERS 24RECEIVER 25RF Amplifier 251st Mixer 25FM Receiver Subsystem 25Voice / Tone Conditioning in Receiver Mode 25Voice Band 26Sub-Audible 26Audio Amplifier 26ANTENNA SWITCHING / LOW-PASS FILTER 26TRANSMITTER 27Keying 27+VTX Supply 27Power Amplifier 27Voice/Tone Conditioning in Transmit Mode 27Voice Band 27Sub-Audible 28MICROCONTROLLER 288. SST-444 ALIGNMENT PROCEDURERECOMMENDED TEST EQUIPMENT 30RADIO PREPARATION 30REFERENCE FREQUENCY 31MODULATION BALANCE 31TRANSMITTER TONE DEVIATION 31TRANSMITTER VOICE DEVIATION 32TRANSMITTER POWER 32RECEIVER SENSITIVITY AND SQUELCH 32RECEIVER NOISE SQUELCH 33SYNTHESIZER 339. SST-444 VOLTAGE CHARTMeasurement Conditions 34SST-444 Voltages 3410. SST-444 SCHEMATIC REFERENCE PARTS LIST 4011. SST-444 CASE ASSEMBLY PARTS LIST 4712. SCHEMATIC AND PART PLACEMENT DRAWINGS 48
4IMPORTANT MAINTENANCE/REPAIR INFORMATIONSurface Mount RepairRITRON surface mount products require special equipment and servicing techniques. Improper servicingtechniques can cause permanent damage to the printed circuit boards and/or components, which is notcovered by RITRON’s warranty. If you are not completely familiar with surface mounted component repairtechniques, RITRON recommends that you defer maintenance to qualified service personnel.Precautions for Handling CMOS DevicesThis radio contains complementary metal-oxide semiconductor (CMOS) devices, which require specialhandling 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 specialprecautions any time you disassemble the radio. Follow the precautions below, which are even morecritical in low humidity environments.1) Storage/transport - CMOS devices that will be stored or transported must be placed in conductivematerial so that all exposed leads are shorted together. CMOS devices must not be inserted intoconventional 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 willwork on the radio/CMOS circuit must be grounded before handling the radio. Normally, the technicianwears 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 CMOSdevices.5) Power/voltage transients - Do not insert or remove CMOS devices with power applied. Check allpower supplies to be used for testing CMOS devices, making sure that no voltage transients arepresent.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 ToolRITRON recommends using a knurled nut tool to remove the slotted knurled nuts that secure the chargeand audio jacks on top of the radio. You will need two sizes of this tool, one for each jack size. MouserCorporation  is one source, stock number 382-0004 (2.5mm jack) and 382-0006 (3.5mm jack). You canreach Mouser sales and distribution center at 1-800-346-6873.Properly Attach the Synthesizer ShieldThe synthesizer shield should not be removed, unless a component must be replaced. This shield issoldered to the main PC board.Re-assembly - Speaker Magnet, Battery Voltage on Connector PinThe speaker magnet will pick up clipped leads and other small metal objects from your bench top. Eventiny objects on the diaphragm will cause the speaker to buzz. Make sure the speaker is free of foreignobjects before reassembling the radio.Radio Transmitter Power MeasurementsThe SST-444 was designed to produce a minimum of 3.5 Watts of Transmitter power at nominal batteryvoltage (+7.2 VDC), throughout the radio’s operating frequency range. Measurements are made with theRITRON SST-SRVBD RF service module connected to the radio antenna terminal. The transmitter wasdesigned with close tolerances to prevent RF power output from exceeding specifications and reducingbattery life.
5SST-444 SPECIFICATIONSGENERALFCC ID: AIERIT13-450FCC Rule Parts: 22, 74, 80, 90Frequency Range: 460 to 470 MHz standardMax. Freq. Separation: 10 MHzRF Channels: Conventional: 4 Channels, Independent TX/RX frequencies.Synthesizer Step Size: 12.5 KHzFrequency Stability: +/-2.5 PPM (-30 to +60 C) TX/RXTone/Code Signaling: CTCSS (Quiet Call)Digital Coded Squelch (Digital Quiet Call)Power Supply: +7.5 VDC, 800 mAH rechargeable NiCd battery pack standard+7.5 VDC, 1500 mAH rechargeable MiMH battery pack optionalBattery Drain:Standby: 52 mASleep: 12 mAAvg. Standby with Power Saver: 24 mAReceive: 125 mATransmit: 1500 mA @ 4 Watts500 mA @ 1 WattBattery Life:Standard battery (800 mAH) @ 90/5/5 Duty Cycle8.2 Hrs, Battery Saver On, TX High Power16.8 Hrs, Battery Saver On, TX Low Power6.2 Hrs, Battery Saver Off, TX High Power10.2 Hrs, Battery Saver Off, TX Low PowerHigh capacity battery (1500 mAH) @ 90/5/5 Duty Cycle13.3 Hrs, Battery Saver On, TX High Power27.3 Hrs, Battery Saver On, TX Low Power10.2 Hrs, Battery Saver Off, TX High Power16.7 Hrs, Battery Saver Off, TX Low PowerDimensions: 4.75”H x 2.2”W x 1.43”DWeight: 11.5 oz. with battery packEnclosure Material: Lexan PolycarbonateEnvironmental: 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" threadedExternal RF Test Jack: Antenna connector with RITRON SST-SRVBD test device
6SST-444 SPECIFICATIONSGENERALEarphone Jack: 3.5 mm, disconnects the internal speaker for external earphone,speaker / microphone, or headset. Also provides cable connectionfor PC programming.Microphone/PTT/Chg Jack: 2.5 mm, for external speaker/microphone, headset or RITRONmodel BC-A wall chargerPush Button Controls:On/Volume UpVolume Down/OffPTTChannelSpeaker Beep Indicators:On/Volume UP Single beep when radio is turned on, followed by increasing audioto adjust volume.Volume Down/Off Decreasing audio to adjust volume, with two tones when unit isturned off.Both Volume Buttons Alternates between Tone Squelch (single beep) and CarrierSquelch (two beeps). If both buttons are held down until the radiobeeps repeatedly, squelch will be disabled.Channel Number of beeps indicates channel.RECEIVERWide band Model Narrow band ModelModulation Acceptance: +/- 7.0 KHz +/- 3.75 KHzSensitivity (12 dB SINAD): 0.25 µV 0.25 µVAdjacent Channel (EIA): -60 dB -50 dBSpurious Rejection: -60 dB -60 dBImage Rejection (EIA): -70 dB -70 dBIntermodulation (EIA): -56 dB -57 dBNoise Squelch Sensitivity: Programmable per channel, factory set for 12 dB SINADFrequency Response: 300 - 3000 Hz, de-emphasizedAudio Output 1 Watt into 8 Ω, with less than 5 % THD @ the earphone jackReceiving System: Dual conversion superheterodyneI.F. System: 1st - 43.65 MHz 2nd - 450 KHzL.O. Injection: Low sideQC/DQC Decode Time: per EIA Standards
7SST-444 SPECIFICATIONSTRANSMITTERRF Power Output: Programmable per channel for high or low powerHigh : 4 Watts (3.5 Watts minimum @ +7.2 VDC)Low: 1 WattWide Mode Narrow ModeEmission Designator: 16K0F3E 11K0F3EDeviation: +/- 5.00 KHz +/- 2.50 KHzFM Hum and Noise: -43 dB -37 dBAudio Distortion: < 3 % < 6 %Spurious and Harmonics: -50 dBcAudio Response: Meets FCC and EIA requirementsTime-out Timer: 60 seconds, programmable
8 INTRODUCTIONGENERALRITRON's SST-444 handheld is a small, programmable two-way radio, designed to operate in the 460-470 MHz professional FM communications band.This handheld features push-button operating controls, with the Push-To-Talk and Channel buttons onone side of the radio. The On / Volume Up and Volume Down / Off, volume and monitor controls are ontop.Each radio can be “dealer or factory” programmed to contain a unique set of operating frequencies andoptions. Selective signaling options include Quiet Call (CTCSS) and Digital Quiet Call (DCS). Transmitterpower, operating bandwidth and battery saver are among the options programmable on a per channelbasis.InspectionEach radio package should include a radio, antenna, rechargeable battery pack, belt clip and any optionalaccessories ordered. Examine the equipment immediately after delivery and report any damages to yourshipping company.Model IdentificationThe SST-444 model, serial number and FCC Identification are displayed on a label located on the back ofthe radio beneath the belt clip.FCC REGULATIONSLicensingThe 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 withinthe limits specified by the station license. The station licensee is also responsible for proper operation andmaintenance of the radio equipment. This includes checking the transmitter frequency and deviationperiodically, using appropriate methods.Safety StandardsThe FCC (with its action in General Docket 79-144, March 13, 1985) has adopted a safety standard forhuman exposure to radio frequency electromagnetic energy emitted by FCC regulated equipment.RITRON follows these safety standards, and recommends that you observe the following guidelines:•DO NOT hold the radio such that the antenna is very close to or touching exposed parts of the body,especially the face or eyes, while transmitting. Keep the radio vertical, two to three inches away whiletalking into the microphone.•DO NOT press the Push-To-Talk except when you intend to transmit.•DO NOT operate radio equipment near electrical blasting caps or in an explosive atmosphere.•DO NOT allow children to play with any radio equipment that contains a transmitting device.•Repair of RITRON products should be performed only by RITRON authorized personnel.
9BATTERY CAREThe handheld is powered by a rechargeable battery, which fits into the radio case (see FIG-1).CHARGINGThe battery pack can lose its charge during storage and shipment, and should be fully charged before theradio is used. Thereafter, the battery should be charged overnight after each day of use, to ensure peakradio performance for the next day. Using the cube charger (model BC-A), the battery should chargecompletely in 12 hours.Note: A new battery must be cycled (charged and discharged) several times before it will reach itsmaximum charge capacity.To charge the battery using a RITRON cube charger - plug the charger cord into the smaller of the twojacks on top of the radio. Then plug the cube into a 110 VAC outlet. The green lamp lights while thebattery 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 usingan optional RITRON drop-in charger (model BCPS-FS). The battery pack may be charged inside oroutside of the radio case.To charge the battery using a drop-in charger (model BCPS-FS) - plug the drop-in charger into a 110 VACoutlet. Set the portable or battery into the charger. Each battery contact must rest on a charger contactpin.Typically, a battery pack’s service life is one year. To ensure maximum service life, follow theseguidelines:•Do not discharge a battery that is already “run down.” If the battery cannot power your radio, rechargethe battery.•Do not overcharge a battery. The standard battery should not be left to charge continuously.•Before storing a battery, charge it for 16 hours. Thereafter, charge the battery for 16 hours once every30 days.With daily use and recharging, a battery’s service life is about one year. It is time to purchase a newbattery:1) When the radio’s transmitter coverage decreases or does not work at all.2) When the radio quits working after just a few hours of use, even with a full overnight charge.3) 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.
10BATTERY CAREBATTERY REPLACEMENTTo take the battery out of the radio, remove the battery door pictured in FIG-1. Use the pull-tab to removethe battery.Slide the replacement battery into the radio case. Make sure the spring contacts are inserted between thebattery and paper insulator. The contacts must not touch the radio PC board.PRECAUTIONS•Use only RITRON-supplied chargers; other chargers might cause fire, explosion, or other damage tothe 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 anexplosion.•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 andruin the battery.•Charging in temperatures above approximately 95°F will not harm the battery, but can reduce itscharge capacity.Fig. 1Battery Replacement
11DESCRIPTION OF CONTROLS AND CONNECTORSAntennaThe flexible antenna radiates and receives radio signals. Before using the radio, be sure the antennabase is threaded fully into the radio’s antenna bushing.VHF and UHF antennas are not interchangeable. Use only the antenna type packaged with the radio. AVHF antenna is pictured in FIG-2. (The UHF antenna is smaller in diameter.)On/Volume UpThis button switches on the radio, then increases the volume if you continue to press.Off/Volume DownThis button decreases the volume, then shuts off the radio if you continue to press.Channel SelectPressing this button selects the next channel. When the maximum number of channels is reached andyou press this button, the radio resets to channel 1.SpeakerThe speaker allows you to hear calls on your channel.Push-To-Talk ButtonThe PTT activates the transmitter, and must be held down while you talk into the microphone. Releasethe PTT button to receive.MicrophoneThe microphone converts your voice into electrical impulses, which are carried with your broadcast toreceiving radios. Hold the radio about two inches away and talk into the microphone while transmitting.Shouting does not improve the listener’s reception.Audio Accessory JackThis jack connects speaker audio to optional accessories, such as a remote speaker/microphone or anearphone. For accessories that have a two-plug connector, the smaller plug is inserted into the chargejack.This jack is also used to program the radio using the optional PC programming kit.Charge JackThe 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.Battery Access (Case Bottom)The battery door on the case bottom may be removed to access the battery. (Refer to the battery sectionof this manual.)Drop-in Charger ContactsTwo charger contacts in the bottom of the SST-444 radio case allow the battery pack to be charged usingan optional RITRON drop-in charger (model BCPS-FS).Jack CoverThis rubber cover seals out dust and moisture, etc. Snap the cover into the audio accessory and chargejack openings when the jacks are not being used.
12DESCRIPTION OF CONTROLS AND CONNECTORS CHON OFF/HOLDVOLUMEBelt Clip InstallationIf 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 screwincluded, 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 theradio case.3) Using the screw that came with this accessory, attach the clip to the radio.AntennaVol Down/OffOn/Vol UpAudio Accessory JackJack CoverCharge JackSpeakerMicrophonePush-to-TalkChannel SelectorBattery Access Door(Case bottom) Battery Charger Contacts(Case bottom)Fig. 2 Controls and Accessory Connectors
13OPERATIONOn-off/VolumeTo switch on the radio - press the on/volume up button.To adjust the volume - press the volume up button until you reach the desired level. You should hearnoise 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 activityon the channel is heard.ReceiveTo hear calls from other users - adjust the volume as desired. The radio can receive broadcasts while thePush-To-Talk button is not being pressed. Whether or not you hear these broadcasts depends upon thesquelch settings.There are two types of squelch used in the SST-444 portable. First is carrier squelch. This lets you hearall broadcasts on your channel strong enough for the radio to detect, and silences noise. Second is one ofthe selective signaling or “tone squelch” formats available on the SST-444. 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. Ifthis happens, ask the caller to repeat his message.MonitorTo monitor the channel - press one of the volume control buttons. When you press the volume up or thevolume down button, squelch turns off and all radio traffic on the channel (and noise) sounds in thespeaker.Selective Signaling SquelchTo activate tone squelch - simultaneously press both of the volume buttons. Hold for a second or twobefore releasing. When tone squelch is turned on, the handheld sounds one beep. When carrier squelchis 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 startbeeping 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.Battery SaverThe handheld has a programmable "battery saver" feature that conserves battery power. The batterysaver constantly checks the radio's transmitter, receiver and controls for activity. If a number of secondspass without the receiver detecting a call, and without the user operating a control, this feature removespower from most of the radio.During this "off-time," any activity restores full power. Every few fractions of a second, the battery saverapplies power to the receiver, checking for broadcasts. It is possible that the first part of an incoming callmight go unheard before activity is detected and power restored. If this happens, the caller can repeat hismessage. Once "radio contact" is made, normal unhurried conversation can follow.
14OPERATIONTransmitNormally, 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 a couple of inches away, talk into themicrophone. Speak in a normal tone, since talking louder will not improve the listener’s reception.Channel SelectionTo change channels - press and release the channel button. The radio will beep a number of times equalto the new channel number. For example, if you select channel 2, the handheld will beep twice. If thehighest channel number is selected and you press the channel button, the radio will reset to channel 1. Aone-channel radio will beep only once when you press the channel button.WHAT THE RADIO TONES MEANThe handheld responds to certain instructions by sounding a beep or series of tones. These tones can tellyou whether the radio is working as you expect.Power On/Self Check “OK”When the handheld is turned on, it will run a quick “self test.” Once the internal system checks confirmbasic functions, the radio sounds a brief “confirmation tone.” The radio is then ready to use.Error TonesHowever, if the “self test” detects a diagnostic error, an error tone sounds. Alternating tones (the secondis longer and lower pitched) indicate the radio frequency synthesizer is malfunctioning. Turn off the radioand try again. A long, low-pitched tone means the battery voltage is too low to operate the radio. In thiscase, recharge the battery. If you cannot correct a problem, consult an authorized Ritron service facility orRitron.Channel SelectWhen the channel button is pressed, the radio beeps a number of times equal to the channel numberselected.Tone SquelchWhen you press and hold both Volume buttons at the same time, a single beep will sound to indicate thattone squelch is on. A "double beep" means that carrier squelch is on.Recharge Battery AlertAs the battery voltage approaches the minimum required “operating voltage” the radio will emit a shortbeep every minute to alert the user that the battery will soon need recharging. Once the battery chargedrops below the required "operating voltage," the radio emits a long, low tone and turns itself off. If youturn the radio back on, it will beep again and shut itself off. Recharge the battery.
15OPERATIONOPTIONAL RADIO TONESThe SST-444 can be programmed using the RITRON PC Programmer for optional alert tones.Receive Squelch ToneA short tone sounds at the end of each received transmission to indicate that you may transmit.Busy Channel Transmit InhibitIf a user is transmitting on your radio frequency without your tone, you will not be allowed to transmit. Theradio will beep a series of long, low tones while the PTT is held down (like a busy signal).Transmitter Time OutA low tone followed by a higher-pitched tone sounds and the transmitter automatically shuts off if you holddown the PTT button longer than the programmed Time-out. The radio automatically switches to receivemode. Authorized service personnel can turn off this feature.
16OPERATIONTROUBLESHOOTINGIf you have trouble operating the handheld, review the radio controls and operation sections. If you thinkthe radio is malfunctioning, check the table below.Problem Possible SolutionsGENERALThe radio does not work at all. Make sure that the battery is installed correctly, as shownin FIG-1.Recharge or replace the battery. (See note 1.)Operating features do not work exactly The radio has been factory or dealer programmed forAs expected. 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 callertransmits. (Note 4.)Recharge the battery. (Note 1.)Your calls cannot be heard in other radios. Make sure that your radio transmits on the receivefrequency of the radio(s) you want to call. (Note 4.)Recharge the battery. (Note 1.)BatteryThe battery loses its charge sooner than Review the battery charging instructions.expected. Conserve the battery. (Note 5.)If the radio is used in extreme cold, warm the radio underyour coat. (Note 6.)Replace the battery. (Note 1.)Error TonesAn error tone sounds when the radio is first See "Error Tones" in the Operation section.switched on.An error tone sounds while you are talking Refer to “Error Tones”(and the transmitter shuts off).
17OPERATIONTROUBLESHOOTINGProblem Possible SolutionsTone Coded SquelchYou cannot screen out calls from users Make sure the channel is programmed with tone squelch.outside of your tone group. Activate Tone (coded) squelch. (Note 7.)You cannot hear Tone coded messages Confirm that the channel is programmed to detect thewhile in Tone (coded) squelch. same code as the calling radio(s) transmits. (Note 7.) Others in your tone group cannot hear your Verify that you transmit the same code as the radio(s) youtone coded messages. call are programmed to detect. (Note 7.)Notes1) Try a battery pack from a working radio. If the radio in question works with that pack, the originalbattery is suspect. Charge the suspect battery as recommended in this manual. Then, if the chargedoriginal battery cannot power the handheld, try charging again with another charger. If the battery stilldoesn’t hold a charge, the pack should probably be replaced. However, if the battery appears to begood after you try the second charger, the first charger might be faulty. If you think that an accessoryis not operating properly, contact your dealer or RITRON. (Radio accessories come with a 90-daylimited warranty.)2) Reception can often be improved by moving a short distance. This effect is more noticeable inside ofbuildings. 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 bothVolume 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’stransmit frequency. If you want to call another unit, you must select a channel that is programmed totransmit the other radio’s receive frequency. However, if you use a repeater, your channel must beprogrammed to work with the repeater’s transmit and receive frequencies. (A radio channel can holdtwo 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 buttonmore 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 coldweather, periodically warm the portable underneath your coat if possible. An optional remotespeaker/microphone would allow you to keep the radio under your coat while transmitting andreceiving.7) In order for radios to communicate using Quiet Call, they must be programmed with the same tonecode. 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.
18PROGRAMMING THE RADIOEach SST-444 may be programmed to operate on up to 4 channels. The SST-444 may be programmedusing its Push-to-Talk switch or an optional RITRON programming kit.PTT (PUSH-TO-TALK) PROGRAMMING allows you to program any channel to one of the radiofrequencies listed in Table 1 and any Quiet Call code listed in Table 2. The radio will transmit and receiveon the programmed table frequency and QC code.PC PROGRAMMING allows you to program any frequency within the band and channel spacing of theradio model. This method also lets you customize the handheld with optional operating features.PTT (PUSH-TO-TALK) PROGRAMMINGPlacing the Radio in PTT Programming Mode1. Turn off the radio by pressing the Volume Down button until the “radio off” prompt sounds.2. Press and hold the PTT button.3. While holding the PTT button, press and hold the Volume On button until a rapid beeping is heard inthe speaker.4. Release the PTT and Volume On buttons. A series of three ascending tones will sound in the speakerindicating that the radio is in PTT program mode.Note: If the radio will not enter PTT program mode, this feature has probably been turned off using theoptional PC programming kit.How to Find Out What Is Already Programmed1. Place the radio in PTT programming mode as described above.2. Press the Channel button to select the radio channel you would like to read out.3. Press the Volume Up button.4. The radio will sound a series of beeps, pause, and then begin another series. Four series of beepswill be heard, with each series representing a digit. The number of beeps in a series is equal to thedigit. (10 beeps = the digit 0)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 Table 1.7. The second two digits represent the QC (CTCSS) tone frequency as shown in Table 2.Note: If you are unable to read out a channel, it has probably been programmed using the PCprogramming kit to a frequency not contained in Table 1.
19PROGRAMMING THE RADIOPTT Programming the RadioFour valid digits must be entered for the radio to accept PTT programming. The first two digits entered isthe frequency code from Table 1, followed by the two digits for the QC code from Table 2.1. Place the radio in PTT programming mode as described above.2. Press the Channel 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.(To enter the digit 0, press the PTT ten times.)4. Pause after the digit is entered, a 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 sound aconfirmation tone to indicate that programming has been accepted.PTT Programming MistakesInvalid Entries An error tone means that you tried to save an invalid entry. No programmingchanges are made in this case. A triple tone will sound next indicating that theradio 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 justlose count, do not press the Volume Up button to store the entry. Instead, startover by turning the radio off and placing the radio in programming mode again.Return To Normal OperationAfter you finish programming, turn the radio off and then on again. The radio will beep when it is ready fornormal operation.
20PROGRAMMING THE RADIOTable 1 – PTT Programming Frequency TableCode Frequency Description Code Frequency Description01 467.7625 J 11 462.6250 Black Dot02 467.8125 K 12 462.6750 Orange Dot03 464.5500 Yellow Dot 13 464.325004 464.5000 Brown Dot 14 464.825005 467.8500 Silver Star 15 469.500006 467.8750 Gold Star 16 469.550007 467.9000 Red Star 17 463.262508 467.9250 Blue Star 18 464.912509 469.2625 19 464.600010 462.5750 White Dot 20 464.7000Table 2 – Quiet Call Codes and FrequenciesQC Freq QC Freq QC Freq QC FreqCode (Hz) Code (Hz) Code (Hz) Code (Hz)01 67.0 16 114.8 31 192.8 46 189.902 71.9 17 118.8 32 203.5 47 196.603 74.4 18 123.0 33 210.7 48 199.504 77.0 19 127.3 34 218.1 49 206.505 79.7 20 131.8 35 225.7 50 229.106 82.5 21 136.5 36 233.6 51 254.107 85.4 22 141.3 37 241.808 88.5 23 146.2 38 250.309 91.5 24 151.4 39 69.410 94.8 25 156.7 40 159.811 97.4 26 162.2 41 165.512 100.0 27 167.9 42 171.313 103.5 28 173.8 43 177.314 107.2 29 179.9 44 No Tone15 110.9 30 186.2 45 183.5COMPUTER SOFTWARE COPYRIGHTSThe RITRON, Inc. products described in this manual include copyrighted RITRON, inc. computerprograms. Laws in the United States and other countries grant to RITRON, inc. certain exclusive rights inits 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 anymanner without the express written permission of RITRON. The purchase of RITRON, inc. products doesnot grant any license or rights under the copyrights or other intellectual property of RITRON, inc., exceptfor the non-exclusive, royalty fee license to use that arises in the sale of a product, or as addressed in awritten agreement between RITRON, inc. and the purchaser of RITRON, inc. products.
21PROGRAMMING THE RADIOPROGRAMMING THE RADIO USING A PC COMPUTERRITRON’s programming kit allows programming of the SST-444 model radios using a PC compatiblecomputer. An adapter cable connects the radio to a computer’s serial communications port. Once thecable is hooked up, the user inserts the diskette provided into his computer’s floppy disk drive and loads asoftware program.This program transfers data between radio and computer memory, and includes on-screen instructionsand 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 theother end with a modular plug. The DB-25 plugs into the computer’s serial port, the modular plug intothe SST-SRVBD modular jack.4) An adapter for use with SST-444 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 portavailable. A hard disk drive is recommended.Programmable FeaturesThe following features may be programmed on a per channel basis, or will affect all channels together.Feature Range Standard Setting Per ChannelAutomatic Inactivity Turn-off Yes - No YesBattery Saver Enable Yes - No YesBattery Saver Off Time - -Beep Volume Level Fixed – Controlled FixedBeep Fixed Volume Level - -Busy Channel Transmit Inhibit Yes - No No √Carrier Only, No Tones or Codes - - √Channel Selection Mode Increment - Enter IncrementDigital Tone Invert RX Yes - No No √Digital Tone Invert TX Yes - No No √Digital Quiet Call (DCS) - - √Disable Monitor Yes - No No √Channel Beep Rate Slow - Fast SlowNarrow Band Channel Yes - No No √Quiet Call (CTCSS) See Table 2 - √Quiet Call Encode Only Yes - No No √Receive Squelch Tone Yes - No No √Squelch Tightener Yes - No No √Transmit Power Low - High High √Transmit Time Out Timer (60 s) Yes - No YesTurn On To Medium Volume Level Yes - No Yes
22PROGRAMMING THE RADIODescriptions of FeaturesAutomatic Inactivity Turn-off - The radio automatically shuts itself off if four hours go by without themicrocontroller 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 remainsidle. The power strobe 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 checksfor a received signal. A long Battery Saver Off Time may cause the user to miss the beginning of the firstmessage when in battery saver mode.Busy Channel Transmit Inhibit - This keeps the radio from broadcasting if the channel is busy, and is oftenused in conjunction with Disable Monitor. If you press the PTT when the channel is busy with a signal notintended for your radio (not carrying your tone code), this feature sounds a "busy" tone in the speaker andkeeps the transmitter turned off.Channel Selection Mode - This feature allows the channel selector to increment or enter the channel. Thechannel number is "beeped out" when the channel button is first pressed. The channel is not changed. Inincrement mode the radio is changed to the next available channel if the channel button is pressed againwithin three seconds. In enter mode the user must press the channel button the number of times equal tothe 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 otherlicensees on a shared channel. QC, DQC or trunking must be used with this option (although, not theEncode Only feature).Quiet Call (CTCSS) - Programming a Quiet Call code allows you to screen out transmissions that do notcarry 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, Quiet Call is turned off during 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 arenot programmed with Quiet Call. Carrier squelch is set for maximum sensitivity at the factory, but may beadjusted to mute weak signalsTransmit Time Out Timer - This feature automatically shuts off the transmitter (ending your call) if you holddown the PTT button continuously for 60 seconds. The radio sounds a tone when the transmitter shutsoff.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.
23SST-444 THEORY OF OPERATIONINTRODUCTIONThe SST-444 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 sidecontaining only surface mounted components.The SST-444 is frequency synthesized, with all functions of the radio controlled by microcontroller.POWER SUPPLY AND VOLTAGE DISTRIBUTIONThe SST-444 is powered by an internal 6-cell rechargeable battery pack. The battery pack supplies powerto the radio via two contact terminals that are connected to the PCB through P302. F301 is a 3A fuse inseries with P302 for short circuit protection. The battery pack may be charged through 2.5 mm chargejack J301 via CR302 and F301. Zener diode CR301 prevents the batteries from discharging through thecharger accessory, stops a reverse voltage from being applied to the battery pack through J301, andprevents a high voltage from being applied to the radio circuitry.SW301 ON/VOL UP switched is pressed to switch on the SST-444, turning on voltage pass transistorQ304 via R302. 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 isremoved from the SST-444 by pressing the VOL DN/OFF switch SW302 until a beep is heard from thespeaker, 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 IC301will also turn on Q202, which turns on voltage pass transistor Q204. With Q204 emitter connected to the+VBATT battery supply, the collector output is connected to the emitter of Q202 through voltage dividerR202/R203, whose values are selected to limit the TX+V voltage to +6 VDC.Power StrobeThe SST-444 handheld includes a power strobe feature, which reduces battery current drain byperiodically removing voltage from part of the radio. The strobe off cycle time is programmable using thePC Programming Kit. The +5VSW power strobe output at Pin 10 of IC301 controls Q306, which switchesthe regulated +5 VDC to the audio processing circuitry and the synthesizer circuitry. This includes IC303A2.5 VDC (Vag) for bias on audio processing circuitry, IC303C audio high pass filter, IC308 and IC305Aaudio low pass filter for sub-audible frequencies, IC305B audio limiting amplifier, IC306 digitalpotentiometers, IC303B audio summing node amplifier, and IC303D audio low pass filter.Low Battery Voltage DetectionBattery voltage is measured at A/D input Pin 16 of IC301 through voltage divider R303/R305. The radiowill emit a periodic beep if low battery voltage is detected, and will turn the radio off if the battery voltagedrops below +5 VDC. This is to protect the microcontroller and its EE memory from corruption due to lowsupply voltage.
24SST-444 THEORY OF OPERATIONREFERENCE OSCILLATORReference 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 frequencysynthesizer 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 4output is also multiplied up to 43.2 MHz by Q105 and its associated circuitry to provide a receiver 2nd localoscillator signal.SYNTHESIZERThe SST-444 radio is built around a common phase-locked loop (PLL) that consists of a voltage-controlledoscillator (VCO) and a frequency synthesizer. The PLL generates both the receiver 1st local oscillator andtransmitter carrier signals. Control signals from microcontroller IC301 and Reference oscillator Y302 arerouted to frequency synthesizer IC401 per the following chart:Pin NumbersClock Data Latch LD T/R SW REF IN REF OUT +5SW +5VIC301 12 5 20 12 11 - 27 10 -Y302-----4--2IC401 18 19 17 2 - 20 1 12 5, 14Q404, CR401, C414 and associated components provide a filtered supply for the VCO oscillator andbuffer amplifiers.Prescaler Divider / Synthesizer ControllerIC401 contains both a prescaler and synthesizer controller. The prescaler squares and divides the VCOoutput present at pin 11 by either 64 or 65, determined by a synthesizer controller logic signal. The exactnumber of times the prescaler is instructed 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 orthe receive/transmit mode switched, a new synthesizer operating frequency is selected. MicrocontrollerIC301 clocks new data into IC401 internal buffer in synchronization with clock pulses. The channelinformation 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 thesynthesizer controller to latch and execute the new data. IC401 utilizes internal circuitry to determinewhether the present VCO output frequency is correct by comparing the phase and frequency of the VCOsignal 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 twoinput signals.The loop filter C429, C427, R419, R420, R418, and C426 transform the Pin 6 output signal to a DCvoltage for application to the VCO tuning varactor CR402. The synthesizer system is “locked” when thephase 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 toPin 8 of IC401, with the output current programmable to 25, 50 or 100% of maximum.
25SST-444 THEORY OF OPERATIONVCO / Buffer AmplifiersQ403, L401, CR402 and associated components form the VCO (Voltage Controlled Oscillator), a resonantcircuit that oscillates at frequencies from 416 MHz in receive (receive frequency - 43.65 MHz) to 470 MHzin transmit. Varying the voltage at CR402 changes the varactor capacitance, which in turn alters the VCOoutput frequency. When in transmit mode a +5 VDC T/RSW signal is applied to Q406, which turns onQ405 to draw current through pin diode CR404 and L403. With CR404 biased on, L402 is effectivelyshorted to ground, shifting the VCO frequency up 43.65 MHz. Q401 and Q402 are buffer amplifiers, withQ401 feeding in the input of the synthesizer at Pin 11, the receiver 1st local oscillator and the transmitterpre-amplifier.Oscillator ModulationWhen the SST-444 is in transmit, modulation balance control IC306E passes TX audio through to theVCO modulation input at R416. TX audio is applied to varactor CR403 to modulate the VCO. TX audio isalso routed to the Pin 1 input of TCVCXO reference oscillator Y302. Low frequency tones modulate thereference oscillator because the synthesizer is not able to track them.DIGITAL POTENTIOMETERSIC306 contains 6 digital potentiometers programmed by IC301, sharing the same clock and data outputsused by the synthesizer and a separate Digital Pot Latch signal from Pin 8. The digital potentiometers areused in conjunction with IC303B, a summing node amplifier used for modulating the VCO and referenceoscillator. IC306A, B, D, E, and F can only be changed through serial programming, and can only beperformed by an authorized licensed RF technician.IC306A is connected through R352 to the Pin 6 input of IC303B. IC306A adjusts the DC output of IC303Bto tune the reference oscillator frequency.IC306B is connected to the Pin 2 Gate control of RF power transistor Q203 to adjust transmitter poweroutput.Volume control IC306C applies the processed voice band signals at IC303D to audio amplifier IC307when in receive mode. Depressing the ON/VOL UP switch SW301 increases the setting of IC306C whileVOL DN/OFF switch SW302 decreases it.Transmitter tone deviation control IC306D applies the output of the selective signaling low-pass filterIC308 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 VCOmodulation input. This will set the ratio of the modulating signal applied to the VCO and the referenceoscillator. IC306E is completely closed in receive mode.Transmitter voice deviation control IC306F applies the processed voice band signals at IC303D to the Pin6 input of IC303B through R349. IC306F is completely closed in receive mode.
26SST-444 THEORY OF OPERATIONRECEIVERAs mentioned before, Q101 switches the regulated +5 VDC to the receiver. The +VRX receiver voltage isswitched at the strobe duty cycle if programmed for power strobe.RF AmplifierA received signal from the antenna passes through a low-pass filter (L207, C216, C217, L206, C101, andC202) to the receiver headend. L101 and the associated capacitors form a bandpass filter ahead of low-noise RF amplifier Q102. L101 and C103 provide a notch at the image frequency, 87.3 MHz below thereceive frequency. The amplified RF signal is applied to a 2-pole bandpass filter consisting of L103, L104,and associated capacitors. This circuit can be tuned for any 10 MHz band between 450 and 470 MHz.1st MixerThe amplified received input signal is applied to the gate of FET mixer Q103. The 1st local oscillatorsignal from the synthesizer module is applied to the source of Q103. L106, C117 and C118 tune the drainoutput of Q103 to 43.65 MHz and apply it to YF101, a 43.65 MHz two-pole crystal filter. Q104 andassociated components amplify the 43.65 MHz IF signal and apply it to the input of the 2nd mixer at Pin 16of IC101.FM Receiver SubsystemA multi-function integrated circuit, IC101 and associated components for the FM-receiver subsystem. Thesubsystem 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 andassociated components. This signal is applied to the 2nd local oscillator input at Pin 1 of IC101. The43.65 MHz signal at Pin 16 and the 2nd local oscillator are mixed, with the resulting 450 KHz output signalappearing at Pin 3. This signal is filtered by a 450 KHz 6-pole ceramic filter YF102 and applied to theinput of the limiting IF amplifier at Pin 5. IC101 Pin 6 is the de-coupled input to the IF amplifier, Pin 7 thelimited IF output signal. An internal quadrature detector, whose center frequency is determined by 450KHz quadrature coil T101, detects the FM IF signal. One input of the quadrature detector is connectedinternally 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 quadratureoutput prior to application to the voice/tone conditioning audio circuitry. Demodulated audio from Pin 9 isapplied to the Pin 10 input of a noise filter/amplifier consisting of R112, C123, C124, R110, R111 andR113. The Pin 11 output of the noise amplifier is applied to a biased noise detector CR103, with theoutput connected to an A/D input of IC301 at Pin 19. The SST-444 is serial programmed to set thesquelch threshold and hysteresis.Voice / Tone Conditioning in Receive ModeSST-444 audio conditioning filter circuits are shared with the transmitter. The same high-passfilter/amplifier (IC303C and associated components) used in receive voice band conditioning is used in thetransmit band. Similarly, the low-pass filter (IC308 and associated components) used for selective signaltone decode filtering is also used for selective signal encoding. Altering circuit configuration with bilateralswitches IC304A, B and C permits the use of the same audio filtering system for both transmit and receivemodes.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 toIC304A for voice band audio processing.
27SST-444 THEORY OF OPERATIONVoice BandBilateral switch IC304A passes the received audio signal to the input of IC303C, which along with itsassociated 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 isswitched in receive to insert C351 into the feedback circuit of IC305B, providing de-emphasis of thereceived audio signal. Bilateral switch IC304B also removes R335 from the Pin 6 input to reduce the gainand prevent limiting. The output from IC305B is applied to the input of IC303D, which along with itsassociated components form an 18dB/octave low-pass filter for frequencies above 3000 Hz. The outputof IC303D is connected to IC306C volume control prior to connection to audio amplifier IC307. The outputof IC303D is also connected to IC306F voice deviation control, which is completely closed in receive modeto prevent received signals from modulating the VCO and reference oscillators.Audio frequency tones from Pin 23 of microcontroller IC301 are applied to the Pin 6 input of IC305B toprovide the SST-444 alert tones.Sub-AudibleBilateral switch IC304C passes the received audio signal to the input of IC305A, which amplifies the signaland applies it to the Pin 2 input of IC308, a 5-pole low-pass filter that attenuates frequencies above 250Hz. The output at Pin 5 is applied to an A/D input of IC301 at Pin 18 for tone decoding. An internal digitalsignal processing routine programmed into microcontroller IC301 is used to decode the correct selectivesignaling code. The output at Pin 5 of IC308 is also connected to tone deviation control IC306D, which iscompletely closed in receive mode to prevent received subaudible tone signals from modulating the VCOand reference oscillators.Audio AmplifierReceive 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 Q07, which then turnson pass transistor Q308 to apply battery voltage to Pin 6 of the audio amp. CR307 prevents aninadvertent DC voltage at J303 from damaging the audio amplifier.ANTENNA SWITCHING / LOW PASS FILTERA low-pass filter comprised of filter L203, C213, C214, L204, C217, L207, and C216 removes harmonicsfrom the transmitter output before applying the RF signal to the antenna. Received signals pass throughthe low-pass filter before entering the receiver RF amplifier circuitry.Two PIN diodes (CR201, CR101) and associated components form the antenna switching circuit. Withthe SST-444 in receive mode, no voltage is applied to the PIN diodes and they do not conduct. Thisreverse biases CR201 to prevent the transmitter amplifier from affecting the receiver tuning and removesCR101 from the receiver input. Incoming signals from the antenna pass through the low-pass filter, thenL206 and C102 to the receiver headend.When the SST-444 is switched into transmit mode, transmitter supply voltage is switched on by Q201 andQ202 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 shuntsthe receiver RF amplifier input to ground. L206 provides sufficient impedance to isolate the transmitterpower from the receiver RF amplifier.
28SST-444 THEORY OF OPERATIONTRANSMITTERKeyingThe SST-444 transmitter is keyed when PTT switch SW304 is depressed. Electret condensermicrophone M301 is connected in series to ground with the PTT switch, which when depressed drawscurrent through M301, SW304, CR304 and R307 to turn on pass transistor Q302. Q302 then turns onQ301 to pull the TX Key Pin 2 input of microcontroller IC301 low. The microcontroller T/R output at Pin 11then goes high to turn on Q202, which turns on pass transistor Q201 to apply +6VDC to the transmitter asdescribed previously. The transmitter can also be keyed through J301 with an audio accessory thatinserts a microphone and PTT switch in series to ground, drawing current through CR304.+VTX SupplyWith the transmitter enabled as described above, the +VTX voltage from Q201 is applied to transmitterRF amplifier Q204. +VTX supply also forward biases the PIN switching diodes CR201 and CR101 aspreviously 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 thePTT switch has been released to allow tone related turn-off codes for squelch tail elimination.Power AmplifierQ204 and associated components amplify the VCO signal and apply it to the input of RF Final amplifiermodule Q203 at Pin 1. The 50Ω output of Q203 is matched to the antenna switching circuitry and appliedto the antenna through the low-pass filter.The RF power output is programmable by a licensed RF technician. The SST-444 can be programmedon a channel-by-channel basis for low or high power operation. The power control digital PotentiometerIC306B is used to adjust the Q203 gate voltage and set RF power output.Voice / Tone Conditioning in Transmit ModeSST-444 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 transmittervoice band. Similarly, the low-pass filter (IC308 and associated components) used for sub-audible tonedecode 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 BandM301 microphone audio is passes through CR304, C334 and is switched by IC304A to the input ofIC303C, which along with its associated components form a high-pass filter/amplifier circuit thatattenuates audio signals below 300 Hz. The output of IC303C is applied to the input of IC305B limitingamplifier. Bilateral switch IC304B switches R335 in parallel with R336, raising the gain of limiting amplifierIC305B for full limiting of the transmitter voice audio. The output of IC305B is applied to the input ofIC303D, which along with its associated components form an 18 dB/octave low-pass filter for frequenciesabove 3 KHz. The output of IC303D is applied to voice deviation control IC306F, which sets the level ofthe processed transmitter audio applied to summing node amplifier IC303B used to modulate the VCOand reference oscillator.
29SST-444 THEORY OF OPERATIONSub-AudibleMicrocontroller IC301 generates the sub-audible selective signaling encode waveforms at Pin 21 andapplies 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 cornerfrequency of the low-pass filter, with C342 switched in by Pin 7 of IC301 to lower the corner frequency forlower tones. The output of IC308 is applied to tone deviation control IC306D, which sets the level of thetransmitter sub-audible encode tones applied to summing node amplifier IC303B used to modulate theVCO and reference oscillator.MICROCONTROLLERThe SST-444 handheld transceiver is electronically controlled by IC301, an 8-bit microcontroller. IC301has four 8-bit A/D inputs for processing analog signals.PIN DESCRIPTION1 RESET is connected to the SST-444 +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 initiatetransmitter operation.3 AUDIO GATE ENABLE controls analog switches IC304A, B and C to configure the shared audioprocessing circuitry for receive operation when LOW, and for transmitter operation when HIGH.4, 25 SERIAL DATA INPUT links the microcontroller to communications from an external data terminalvia J303 RING connection. This allows programming of the SST-444 EEPROM memory used tostore 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 ison a channel programmed for a CTCSS tone below 150 Hz. This output is in a tri-state OPENcondition for all other tones.8 DIGITAL POT LATCH sends a single positive pulse after data has been sent to IC306 to latch thenew 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 fromvarious circuits in the radio, thus conserving battery life. In normal transmit or receive mode thisoutput is LOW.11 T/R SWITCH output is connected to the Synthesizer circuitry to shift the frequency of the VCOoscillator 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 digitalpotentiometers IC306 when programming these devices.
30SST-444 THEORY OF OPERATIONPIN DESCRIPTION13 +V SW output is HIGH when the radio is turned on, keeping pass transistor Q304 turned on viaQ303 to supply power to the radio.14 GROUND15 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 toturn 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 speakeraudio level and turn off the radio. This input also serves as CHANNEL input, and goes to 2.5VDC when channel selector switch SW303 is pressed to change the radio to the nextprogrammed channel.18 A/D input TONE DECODE accepts the received QC (CTCSS) and DQC (DCS) waveforms aftersignal processing for decode analysis.19 A/D input RSSI is used to measure the output voltage of the noise detector for squelch detection.20 LATCH output goes LOW to allow serial data to frequency synthesizer IC401 and goes HIGH tolatch the data, allowing the synthesizer to execute the new frequency information.21 TONE ENCODE outputs generate the QC (CTCSS) and DQC (DCS) encode waveforms forsignal 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 speakeraudio or radio alert tones.23 BEEP output generate the radio alert tones heard in the speaker.24, 26 UNUSED27 REFERENCE OSCILLATOR INPUT has the 3.6 MHz reference signal from the synthesizer.28 +5 VDC VDD supply voltage.
31SST-444 ALIGNMENT PROCEDUREAn authorized RF service technician must perform test and alignment of the SST-444. Do not attemptservice of the SST-444 if not completely familiar with the operation of frequency synthesized radiooperation. The SST-444 can operate in either Narrow Band (2.5 KHz deviation) or Wide Band (5 KHzdeviation) systems.RECOMMENDED TEST EQUIPMENT1) 0 to +15 VDC, 2A current-limited power supply 3) Oscilloscope (to 20 MHz)2) RF Communications Test Set (to 470 MHz) with: 4) VTVM or DMM- FM Deviation Meter- RF Wattmeter 5) RITRON PC Programming Kit- Frequency Counter (to 470 MHz)- SINAD Measuring Device 6) RITRON SST-SRVBD Test ModuleRADIO PREPARATION1) 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-444 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-444 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 programmingkit software installed) to the SST-SRVBD test assembly3) 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 AlignmentFrequency Transmit frequencyMod Bal Modulation balanceTone QC/DQC tone encode deviation – wide bandQC/DQC tone encode deviation – narrow bandVoice Voice deviation with no tone – wide bandVoice deviation with no tone – narrow bandVoice deviation with tone – wide bandVoice deviation with tone – narrow bandPower Low transmitter powerHigh transmitter power8) After you have completed alignment of the SST-444, turn the radio off. This will remove the testfrequencies and return to operation on the customer’s programmed frequencies.
32SST-444 ALIGNMENT PROCEDUREREFERENCE FREQUENCY1) Make sure that 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 theright arrow to raise the frequency.7) Press the “Save” button to store the new alignment setting or “Cancel” to leave setting unchanged.MODULATION BALANCETransmitter 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 thetop 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 DEVIATIONTransmitter 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 deviationor the right arrow to raise deviation.6) Press the “Save” button to store the new alignment setting or “Cancel” to leave setting unchanged.
33SST-444 ALIGNMENT PROCEDURETRANSMITTER VOICE DEVIATIONTransmitter 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 deviationor the right arrow to raise deviation.6) Press the “Save” button to store the new alignment setting or “Cancel” to leave setting unchanged.TRANSMITTER POWERTransmitter 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 poweror the right arrow to raise power.6) Press the “Save” button to store the new alignment setting or “Cancel” to leave setting unchanged.RECEIVER SENSITIVITY AND SQUELCHThe SST-444 receiver is factory tuned for a frequency range of 460 - 470 MHz. The SST-444 receiver isconfigured from the factory for Wide Band operation, with a Narrow Band Model available as an option.The SST-444 receiver bandwidth is configured on a per radio basis, it cannot be switched on a perchannel basis.The receiver may be tuned to any 10 MHz frequency band between 450-470 MHz.1) Program the radio to a receive frequency in the middle of the desired 10 MHz band.2) Set the RF communications test set generator to a frequency exactly 87.3 MHz below theprogrammed receive frequency at a RF level of approximately –40 dB. Modulate the RF signal with a1 KHz tone at 3 KHz deviation for wide band, 1.5 KHz deviation for low band.3) Connect an 8-Ohm speaker to the 3.5mm audio jack on the SST-SRVBD test assembly.4) Adjust L101 for the minimum received signal at this image frequency.
34SST-444 ALIGNMENT PROCEDURE5) Set the RF Communications Test Set 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 KHzdeviation for low band.6) Adjust L103 and L104 for the best receiver SINAD as measured across the 8-Ohm speaker.7) Check receiver sensitivity at the lowest and highest operating frequencies and make slight adjustmentto L103 and L104 to balance between the two, if necessary.RECEIVER NOISE SQUELCHThe 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 tobetween 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.SYNTHESIZERThe synthesizer is preset at the factory for operation between 460 and 470 MHz. There is no manualadjustment to center the control voltage, with all adjustment performed by the factory selection of fixedcapacitor C413. Do not attempt to adjust the synthesizer control unless a key component in thesynthesizer has been replaced. Key components do not include the Y302 reference frequency TCVCXOor 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 andpowered up at 7.5 VDC. The following procedure defines testing of the VCO control voltage:1) Select the channel that has the lowest receive frequency.2) Connect a VTVM, DVM or oscilloscope to Test Point 1 and measure the VCO control voltage. Thisvoltage should be no less than 1.5 VDC.3) Select the channel that has the highest receive frequency and measure Test Point 1. The controlvoltage 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) Replace C413 with a capacitor value that allows VCO control voltages between 1.5 and 4.5 VDCfor the operating frequencies desired. Decreasing the value of C413 will raise the operatingfrequency of the VCO while increasing the value will lower the VCO frequency.c) Replace the top of the synthesizer shield.
35SST-444 VOLTAGE CHARTMeasurement ConditionsSupply 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-444 portable is constructed with grounding sub-planes, use a systemground in the same proximity as the circuit being measured. All readings indicated as GND are truesystem ground.KEY: All measurements are in VDC unless indicated otherwise.NC = No connectionGND = Ground* = Voltage is strobed in Power Saver mode→= See note in right columnSST-444 VOLTAGESDEVICE PIN Transmit Receive Standby DESCRIPTIONCR101 1 0.7 0.0 0.0 TX/RX switching2NCNCNC3 GND GND GNDCR102 1 GND GND GND Voltage clamp2 GND GND GND30.0 0.0 *CR103 1 GND GND GND Noise detection20.0 →*→ amplified receiver noise30.0 < 0.5 *CR201 1 1.4 0.0 0.0 TX/RX switching2NCNCNC3 0.7 0.0 0.0CR301 C 7.5 7.5 7.5 Over voltage protectionA GND GND GNDCR302 C 7.5 7.5 7.5 Reverse voltage protectionA 2.2 4.8 4.8CR303 1 6.8 6.8 6.8 Turn-on detection2 4.2 4.2 4.23 6.1 6.1 6.1CR304 1 2.0 4.7 4.7 PTT switching2 2.2 4.7 4.73 2.4 5.0 5.0CR305 1 GND GND GND Voltage clamp2 5.0 5.0 5.03 0.0 0.0 0.0CR306 1 2.4 2.4 2.4 Voltage clamp2NCNCNC3 2.4 2.4 2.4CR307 C 7.5 7.5 7.5 Reverse voltage protectionA0.0 →*→ receive audio amp output123SOT-23
36SST-444 VOLTAGE CHARTDEVICE PIN Transmit Receive Standby DESCRIPTIONCR401 1 5.0 5.0 * Biasing24.8 4.8 *3NCNCNCCR402 1 GND GND GND VCO tuning2NCNCNC3→→ *→ 1.5 – 4.5 VDC VCO tuning voltageCR403 1 GND GND GND VCO modulation2NCNCNC32.4 2.4 *CR404 1 0.8 0.0 * TX/RX VCO switching2NCNCNC30.0 4.8 *IC101 1 0.0 4.7 * RX FM-IF subsystem2NCNCNC30.0 3.8 *40.0 4.7 *50.0 3.8 *60.0 3.8 *70.0 3.8 *80.0 4.7 *90.0 2.0 *10 0.0 0.6 *11 0.0 2.4 *12 0.0 0.0 *13 NC NC NC14 NC NC NC15 GND GND GND16 0.0 1.7 *IC301 1 5.0 5.0 5.0 Microcontroller2 0.0 5.0 5.03 5.0 0.0 0.04 0.0 0.0 0.05 0.0 0.0 0.06 0.0 0.0 0.07 0.0 0.0 0.08 0.0 0.0 0.09→→→→ 0.0 VDC on Channel 1 else 5.0 VDC10 0.0 0.0 *11 5.0 0.0 0.012 5.0 5.0 *13 5.0 5.0 5.014 GND GND GND15 5.0 5.0 5.016 4.2 4.2 4.217 5.0 5.0 5.018 2.4 2.4 *19 0.0 0.5 *20 5.0 5.0 5.021 →2.4 * → 0-5 VDC tone encode waveform22 0.0 5.0 0.023 0.0 0.0 0.024 NC NC NC25 0.0 0.0 0.026 NC NC NC27 →→→→ 3.6 MHz clock signal28 5.0 5.0 5.0
37SST-444 VOLTAGE CHARTDEVICE PIN Transmit Receive Standby DESCRIPTIONIC302 1 GND GND GND EEPROM2 GND GND GND3 GND GND GND4 GND GND GND5 0.0 0.0 0.06 0.0 0.0 0.07 GND GND GND8 5.0 5.0 5.0IC303 1 2.4 2.4 * Audio processing22.4 2.4 *32.4 2.4 *45.0 5.0 *52.4 2.4 *62.4 2.4 *72.4 2.4 *82.4 2.4 *92.4 2.4 *10 2.4 2.4 *11 GND GND GND12 2.4 2.4 *13 2.4 2.4 *14 2.4 2.4 *IC304 1 0.0 0.0 * Audio signal switching22.4 2.4 *32.4 2.4 *42.4 2.4 *50.0 2.5 *6 GND GND GND7 GND GND GND8 GND GND GND9 5.0 0.0 0.010 5.0 0.0 0.011 5.0 0.0 0.012 2.4 2.4 *13 NC NC NC14 0.0 2.4 *15 0.0 2.4 *16 5.0 5.0 5.0IC305 1 2.4 2.4 * Audio processing22.4 2.4 *32.4 2.4 *4 GND GND GND52.4 2.4 *62.4 2.4 *72.4 2.4 *85.0 5.0 *
38SST-444 VOLTAGE CHARTDEVICE PIN Transmit Receive Standby DESCRIPTIONIC306 1 2.0 2.0 * Audio signal level control23.8 0.0 *3 GND GND GND40.0 2.5 *52.4 2.4 *62.4 2.4 *72.4 2.4 *80.0 0.0 *95.0 5.0 *10 GND GND GND11 NC NC NC12 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 NC NC Audio amplifier2 0.0 0.0 0.03 GND GND GND4 GND GND GND5 0.0 3.7 0.06 0.0 7.5 0.07 0.0 3.7 0.08 NC NC NCIC308 1 2.4 2.4 * Tone low pass filter22.4 2.4 *3 GND GND GND45.0 5.0 *52.4 2.4 *62.4 2.4 *75.0 5.0 *83.2 3.2 *IC309 1 7.5 7.5 7.5 +5 VDC voltage regulator2 GND GND GND3 7.5 7.5 7.54NCNCNC5 5.0 5.0 5.0
39SST-444 VOLTAGE CHARTDEVICE PIN Transmit Receive Standby DESCRIPTIONIC401 1 →→→→ 3.6 MHz clock signal2 5.0 5.0 * Frequency synthesizer3NCNCNC4NCNCNC5 5.0 5.0 5.06→→ *→ 1.5 – 4.5 VDC VCO tuning voltage7 GND GND GND82.2 2.2 *9NCNCNC10 2.4 2.4 *11 2.4 2.4 *12 5.0 5.0 *13 NC NC NC14 5.0 5.0 5.015 0.0 0.0 *16 NC NC NC17 5.0 5.0 5.018 5.0 5.0 *19 0.0 0.0 *20 2.2 →2.2 →*→ 14.4 MHz reference signalQ 101 1 5.0 4.3 * RX +V switching25.0 5.0 *30.0 4.7 *Q 102 1 0.0 0.7 * RX RF amplifier2 GND GND GND30.0 3.0 *Q 103 1 0.0 4.7 * RX mixer20.0 0.0 *30.0 1.8 *Q 104 1 0.0 0.7 * RX IF amplifier2 GND GND GND30.0 1.2 *Q 105 1 0.0 0.7 * RX 2nd LO multiplier/amp2 GND GND GND30.0 4.6 *Q 201 1 6.8 7.5 7.5 TX +V switching2 7.5 7.5 7.53 6.0 0.0 0.0Q 202 1 5.0 0.0 0.0 TX +V switching2 4.3 0.0 0.03 6.8 7.5 7.5Q 203 1 0.0 0.0 0.0 TX RF final amplifier2 3.8 0.0 0.03 7.5 7.5 7.54 0.0 0.0 0.05 GND GND GNDQ 204 1 0.9 0.0 0.0 TX RF driver amplifier2 0.3 0.0 0.03 6.0 0.0 0.0
40SST-444 VOLTAGE CHARTDEVICE PIN Transmit Receive Standby DESCRIPTIONQ 301 1 5.0 0.0 0.0 PTT detection2 GND GND GND3 0.0 5.0 5.0Q 302 1 4.3 5.0 5.0 PTT detection2 5.0 5.0 5.03 5.0 0.0 0.0Q 303 1 5.0 5.0 5.0 Battery +V switching2 4.3 4.3 4.33 6.8 6.8 6.8Q 304 1 6.8 6.8 6.8 Battery +V switching2 7.5 7.5 7.53 7.5 7.5 7.5Q 306 1 4.3 4.3 5.0 +5V switching2 5.0 5.0 5.035.0 5.0 *Q 307 1 0.0 5.0 0.0 Audio amplifier enable2 0.0 4.3 0.03 7.5 6.8 7.5Q 308 1 7.5 6.8 7.5 Audio amplifier +V switching2 7.5 7.5 7.53 0.0 7.5 0.0Q 401 1 0.7 0.7 * VCO buffer amplifier2 GND GND GND32.9 2.9 *Q 402 1 0.7 0.7 * VCO buffer amplifier2 GND GND GND32.8 2.8 *Q 403 1 2.3 2.3 * VCO oscillator21.6 1.6 *34.3 4.3 *Q 404 1 4.7 4.7 * VCO voltage de-coupling24.3 4.3 *35.0 5.0 *Q 405 1 0.0 4.3 * TX/RX VCO switching24.3 4.3 *34.2 0.0 *Q 406 1 0.0 4.3 * TX/RX VCO switching2 GND GND GND34.3 0.0 *
41SST-444 SCHEMATIC REFERENCE PARTS LISTNOTE: This parts list reflects the most current component values. If a component value given in theschematic differs from this list, the parts list should be considered the most current.Last Update: June 13, 2000Ref Ritron PN Description X Y Theta LocCAPACITORSC101 151103A3 3.3pf NPO 0805 CHIP CAPACITOR 1065 3824 270 TopC102 151102A2 2.2PF NPO 0805 50V CHIP CAP 949 3929 180 TopC103 15110120 12PF NPO 0805 50V CHIP CAP 791 4059 90 TopC104 15110220 22PF NPO 0805 50V CHIP CAP 909 3824 270 TopC105 15110180 18PF NPO 0805 50V CHIP 1018 3608 270 TopC106 15110180 18PF NPO 0805 50V CHIP 869 3716 180 TopC107 15181102 .001uF CAPACITOR, CHIP, 0402, X7R, 5/10% 734 3620 180 TopC108 15181102 .001uF CAPACITOR, CHIP, 0402, X7R, 5/10% 675 3519 90 TopC109 151106A8 6.8PF NPO 0805 50V CHIP 637 3994 90 TopC110 151103A9 3.9PF NPO 0805 50V CHIP 557 3993 270 TopC111 151103A3 3.3pf NPO 0805 CHIP CAPACITOR 516 4099 180 TopC112 151103A3 3.3pf NPO 0805 CHIP CAPACITOR 382 4099 180 TopC113 15110100 10PF NPO 0805 50V CHIP CAP 476 3993 270 TopC114 151108A2 8.2PF NPO 0805 50V CHIP 275 4059 270 TopC115 15110150 15PF 0805 NPO 50V CHIP CAP 380 3786 0 TopC116 15182103 .01uF CAPACITOR, CHIP, 0402,Z5U,5/10/20 276 3382 180 TopC117 15110150 15PF 0805 NPO 50V CHIP CAP 199 3598 180 TopC118 15110470 47PF NPO 0805 50V CHIP 160 3491 90 TopC119 15181472 .0047uF CAPACITOR, CHIP, 0402, X7R,5/10% 485 3367 270 TopC120 151108A2 8.2PF NPO 0805 50V CHIP 407 3548 0 BottomC121 15181102 .001uF CAPACITOR, CHIP, 0402, X7R, 5/10% 138 947 90 BottomC122 152B6106 10uF 10V 3.4 X 2.8 CHIP TANTALUM 451 1669 0 BottomC123 15181102 .001uF CAPACITOR, CHIP, 0402, X7R, 5/10% 450 946 90 BottomC124 15181102 .001uF CAPACITOR, CHIP, 0402, X7R, 5/10% 349 884 0 BottomC125 15119104 .1uF X7R 0805 25V CERAMIC CHIP CAP 350 1364 0 BottomC126 15119104 .1uF X7R 0805 25V CERAMIC CHIP CAP 441 1557 0 BottomC127 15119104 .1uF X7R 0805 25V CERAMIC CHIP CAP 69 2203 0 BottomC128 15119104 .1uF X7R 0805 25V CERAMIC CHIP CAP 225 2114 270 BottomC129 15119104 .1uF X7R 0805 25V CERAMIC CHIP CAP 392 1802 0 BottomC130 15182103 .01uF CAPACITOR, CHIP, 0402,Z5U,5/10/20 571 904 90 BottomC131 15110330 33PF NPO 0805 50V CHIP 38 1263 0 BottomC132 15110330 33PF NPO 0805 50V CHIP 64 1156 270 BottomC133 15119104 .1uF X7R 0805 25V CERAMIC CHIP CAP 69 2100 0 BottomC134 15182103 .01uF CAPACITOR, CHIP, 0402,Z5U,5/10/20 39 1635 90 TopC135 15110220 22PF NPO 0805 50V CHIP CAP 171 1533 180 BottomC201 15180101 100pF CAPACITOR, CHIP, 0402, COG, 5% 1302 3153 90 BottomC202 15181102 .001uF CAPACITOR, CHIP, 0402, X7R, 5/10% 871 3384 270 BottomC203 15180101 100pF CAPACITOR, CHIP, 0402, COG, 5% 997 3248 90 BottomC204 152A8105 1MFD 16V ~3.2 X 1.6~ CHIP TANTALUM 1100 3496 270 TopC205 15181102 .001uF CAPACITOR, CHIP, 0402, X7R, 5/10% 1019 3494 90 TopC206 15180101 100pF CAPACITOR, CHIP, 0402, COG, 5% 1748 3308 90 BottomC207 15181102 .001uF CAPACITOR, CHIP, 0402, X7R, 5/10% 1748 3104 90 BottomC208 15110100 10PF NPO 0805 50V CHIP CAP 1796 2406 90 TopC209 15119104 .1uF X7R 0805 25V CERAMIC CHIP CAP 1427 2284 90 BottomC210 15180101 100pF CAPACITOR, CHIP, 0402, COG, 5% 1492 2264 90 BottomC211 15110560 56PF NPO 0805 50V CHIP CAPACITOR 1715 2211 270 TopC212 15110101 100PF NPO 0805 50V CHIP CAP 1788 3787 90 TopC213 151103A9 3.9PF NPO 0805 50V CHIP 1682 3828 180 TopC214 15110100 10PF NPO 0805 50V CHIP CAP 1652 4093 90 TopC215 FACTORY SELECT 1439 4093 90 TopC216 15110101 100PF NPO 0805 50V CHIP CAP 953 4136 90 TopC217 151105A6 5.6PF NPO 0805 50V CHIP CAPACITOR 1035 4136 90 TopC301 15181102 .001uF CAPACITOR, CHIP, 0402, X7R, 5/10% 774 817 180 Bottom
42SST-444 SCHEMATIC REFERENCE PARTS LISTRef Ritron PN Description X Y Theta LocC302 15181102 .001uF CAPACITOR, CHIP, 0402, X7R, 5/10% 275 522 270 TopC303 152B4226 22uF 6.3V 3.4 X 2.8 CHIP TANTALUM CAP 199 647 180 TopC304 15181102 .001uF CAPACITOR, CHIP, 0402, X7R, 5/10% 1261 4590 90 BottomC305 15180101 100pF CAPACITOR, CHIP, 0402, COG, 5% 1027 427 0 TopC306 15180101 100pF CAPACITOR, CHIP, 0402, COG, 5% 613 402 270 TopC307 15182103 .01uF CAPACITOR, CHIP, 0402,Z5U,5/10/20 20 4621 270 TopC308 15111102 .001MF X7R 0805 50V CHIP CAP 0 0 0 BottomC309 15182103 .01uF CAPACITOR, CHIP, 0402,Z5U,5/10/20 496 1867 90 BottomC310 15119104 .1uF X7R 0805 25V CERAMIC CHIP CAP 1107 3264 0 BottomC311 15181102 .001uF CAPACITOR, CHIP, 0402, X7R, 5/10% 1229 2967 90 BottomC312 15182103 .01uF CAPACITOR, CHIP, 0402,Z5U,5/10/20 544 4622 270 TopC313 15181102 .001uF CAPACITOR, CHIP, 0402, X7R, 5/10% 169 3033 270 TopC314 15181102 .001uF CAPACITOR, CHIP, 0402, X7R, 5/10% 1280 2568 180 BottomC315 15181102 .001uF CAPACITOR, CHIP, 0402, X7R, 5/10% 1280 2271 180 BottomC316 15182103 .01uF CAPACITOR, CHIP, 0402,Z5U,5/10/20 826 2291 180 TopC317 15181102 .001uF CAPACITOR, CHIP, 0402, X7R, 5/10% 704 2321 0 BottomC318 15181102 .001uF CAPACITOR, CHIP, 0402, X7R, 5/10% 826 2371 180 TopC319 15181102 .001uF CAPACITOR, CHIP, 0402, X7R, 5/10% 704 2407 0 BottomC320 15181102 .001uF CAPACITOR, CHIP, 0402, X7R, 5/10% 1280 2410 180 BottomC321 15181102 .001uF CAPACITOR, CHIP, 0402, X7R, 5/10% 1280 2488 180 BottomC322 15180101 100pF CAPACITOR, CHIP, 0402, COG, 5% 1280 2311 180 BottomC323 15181102 .001uF CAPACITOR, CHIP, 0402, X7R, 5/10% 1280 2771 180 BottomC324 15119104 .1uF X7R 0805 25V CERAMIC CHIP CAP 969 2221 0 TopC325 15180101 100pF CAPACITOR, CHIP, 0402, COG, 5% 1280 2687 180 BottomC326 15180101 100pF CAPACITOR, CHIP, 0402, COG, 5% 1280 2607 180 BottomC327 15181102 .001uF CAPACITOR, CHIP, 0402, X7R, 5/10% 1280 2371 180 BottomC328 15181102 .001uF CAPACITOR, CHIP, 0402, X7R, 5/10% 704 2446 0 BottomC329 15181102 .001uF CAPACITOR, CHIP, 0402, X7R, 5/10% 638 2501 270 BottomC330 15181102 .001uF CAPACITOR, CHIP, 0402, X7R, 5/10% 704 2571 0 BottomC331 15181102 .001uF CAPACITOR, CHIP, 0402, X7R, 5/10% 704 2610 0 BottomC332 15181102 .001uF CAPACITOR, CHIP, 0402, X7R, 5/10% 737 2672 270 BottomC333 152A6475 4.7UF 10V A-SIZE TANTALUM CHIP CAP 502 2703 180 TopC334 15119104 .1uF X7R 0805 25V CERAMIC CHIP CAP 95 2765 180 BottomC335 15180101 100pF CAPACITOR, CHIP, 0402, COG, 5% 420 2842 270 BottomC336 15181102 .001uF CAPACITOR, CHIP, 0402, X7R, 5/10% 454 3156 90 BottomC337 152B6106 10uF 10V 3.4 X 2.8 CHIP TANTALUM 724 3558 270 BottomC338 15180101 100pF CAPACITOR, CHIP, 0402, COG, 5% 254 3129 90 TopC339 15119104 .1uF X7R 0805 25V CERAMIC CHIP CAP 245 2945 270 TopC340 15111333 .033MFD X7R 0805 50V CHIP CAP 366 2665 270 BottomC341 15182103 .01uF CAPACITOR, CHIP, 0402,Z5U,5/10/20 585 2328 270 BottomC342 15110821 820PF NPO 0805 50V CHIP CAP 638 2964 180 BottomC343 15111122 .0012MF X7R 0805 50V CHIP 637 3045 180 BottomC344 15181472 .0047uF CAPACITOR, CHIP, 0402, X7R,5/10% 184 2436 0 TopC345 15181472 .0047uF CAPACITOR, CHIP, 0402, X7R,5/10% 269 2436 0 TopC346 152A8105 1MFD 16V ~3.2 X 1.6~ CHIP TANTALUM 614 2232 90 TopC347 15180180 18pF CAPACITOR, CHIP, 0402, COG, 5% 286 2500 90 TopC348 15119473 .047uF X7R 0805 25V CHIP CAPACITOR 474 2595 0 TopC349 15111333 .033MFD X7R 0805 50V CHIP CAP 127 2621 90 BottomC350 15180101 100pF CAPACITOR, CHIP, 0402, COG, 5% 493 3156 90 BottomC351 15181222 .0022uF CAPACITOR, CHIP, 0402, X7R,5/10% 19 2670 180 TopC352 15180100 10pF CAPACITOR, CHIP, 0402, COG, 5% 436 3228 90 TopC353 15182103 .01uF CAPACITOR, CHIP, 0402,Z5U,5/10/20 593 3133 180 TopC354 15180221 220pF CAPACITOR, CHIP, 0402, COG, 5% 379 2436 90 BottomC355 15181102 .001uF CAPACITOR, CHIP, 0402, X7R, 5/10% 301 2435 90 BottomC356 15181102 .001uF CAPACITOR, CHIP, 0402, X7R, 5/10% 258 2393 90 BottomC357 15181102 .001uF CAPACITOR, CHIP, 0402, X7R, 5/10% 153 2415 180 TopC358 15181102 .001uF CAPACITOR, CHIP, 0402, X7R, 5/10% 585 2498 90 BottomC359 15180100 10pF CAPACITOR, CHIP, 0402, COG, 5% 490 2589 90 BottomC360 15181102 .001uF CAPACITOR, CHIP, 0402, X7R, 5/10% 470 2270 270 TopC361 15180101 100pF CAPACITOR, CHIP, 0402, COG, 5% 492 2074 0 TopC362 15119104 .1uF X7R 0805 25V CERAMIC CHIP CAP 981 752 270 Bottom
43SST-444 SCHEMATIC REFERENCE PARTS LISTRef Ritron PN Description X Y Theta LocC363 152B6106 10uF 10V 3.4 X 2.8 CHIP TANTALUM 1231 427 0 TopC364 15119104 .1uF X7R 0805 25V CERAMIC CHIP CAP 1058 503 180 BottomC365 01503212 220MF 10V ELT CAPACITOR, 5mm HEIGHT 1491 5052 0.302 TopC366 15119104 .1uF X7R 0805 25V CERAMIC CHIP CAP 1482 659 90 BottomC367 15119104 .1uF X7R 0805 25V CERAMIC CHIP CAP 1357 798 90 BottomC368 15181102 .001uF CAPACITOR, CHIP, 0402, X7R, 5/10% 247 2708 270 BottomC369 15180101 100pF CAPACITOR, CHIP, 0402, COG, 5% 664 2454 90 TopC401 15180101 100pF CAPACITOR, CHIP, 0402, COG, 5% 1566 1966 270 TopC402 151101A5 1.5PF NPO 0805 50V CHIP 1640 194 90 TopC403 15181102 .001uF CAPACITOR, CHIP, 0402, X7R, 5/10% 1680 1828 90 TopC404 15181102 .001uF CAPACITOR, CHIP, 0402, X7R, 5/10% 1066 1850 180 TopC405 15180101 100pF CAPACITOR, CHIP, 0402, COG, 5% 1353 2013 180 TopC406 151101A5 1.5PF NPO 0805 50V CHIP 1182 1785 270 TopC407 151104A7 4.7PF 0805 50V CHIP CAP. 1463 1604 0 TopC408 151104A7 4.7PF 0805 50V CHIP CAP. 1572 1634 270 TopC409 15119104 .1uF X7R 0805 25V CERAMIC CHIP CAP 980 1766 90 TopC410 151104A7 4.7PF 0805 50V CHIP CAP. 1355 158 270 TopC411 15180101 100pF CAPACITOR, CHIP, 0402, COG, 5% 1262 130 270 TopC412 15181102 .001uF CAPACITOR, CHIP, 0402, X7R, 5/10% 1047 1788 90 TopC413 151101A8 1.8PF NPO 0805 50V CHIP 1462 1441 270 TopC414 152B6106 10uF 10V 3.4 X 2.8 CHIP TANTALUM 722 1625 0 TopC415 15181102 .001uF CAPACITOR, CHIP, 0402, X7R, 5/10% 1535 969 270 TopC416 15180101 100pF CAPACITOR, CHIP, 0402, COG, 5% 1731 1114 270 TopC417 15180101 100pF CAPACITOR, CHIP, 0402, COG, 5% 1538 1356 90 TopC418 15180101 100pF CAPACITOR, CHIP, 0402, COG, 5% 677 1121 180 TopC419 15181102 .001uF CAPACITOR, CHIP, 0402, X7R, 5/10% 678 1201 180 TopC420 15181102 .001uF CAPACITOR, CHIP, 0402, X7R, 5/10% 678 1240 180 TopC421 15180101 100pF CAPACITOR, CHIP, 0402, COG, 5% 1053 1576 180 TopC422 15110100 10PF NPO 0805 50V CHIP CAP 1119 1512 180 TopC423 151101A0 1.0PF NPO 0805 50V CHIP 1256 1400 0 TopC424 151108A2 8.2PF NPO 0805 50V CHIP 1187 1252 270 TopC425 15180101 100pF CAPACITOR, CHIP, 0402, COG, 5% 1069 937 90 TopC426 15111222 .0022uF X7R 0805 50V CHIP CAPACITOR 832 922 180 TopC427 152AB334 .33MF 35V ~3.2X1.6~ CHIP TANTALUM 812 1015 0 TopC428 15180101 100pF CAPACITOR, CHIP, 0402, COG, 5% 855 1473 270 TopC429 15111333 .033MFD X7R 0805 50V CHIP CAP 1029 1015 0 TopC430 15180101 100pF CAPACITOR, CHIP, 0402, COG, 5% 971 1460 270 TopC431 15182103 .01uF CAPACITOR, CHIP, 0402,Z5U,5/10/20 687 1393 180 TopC432 15180101 100pF CAPACITOR, CHIP, 0402, COG, 5% 766 1100 180 TopC433 15180101 100pF CAPACITOR, CHIP, 0402, COG, 5% 932 1460 90 TopC434 15180101 100pF CAPACITOR, CHIP, 0402, COG, 5% 1101 1264 0 TopC435 15180101 100pF CAPACITOR, CHIP, 0402, COG, 5% 687 1355 180 TopDIODESCR101 48D100A2 MA4CP101A PIN DIODE, SOT-23 1178 3820 90 TopCR102 48E1005G MMBD-352LT1 SCHOTTKY DIODE SOT23 908 3608 270 TopCR103 48A1005C MMBD7000, DUAL DIODES IN SERIES, SOT-23 356 2147 0 BottomCR201 48D100A2 MA4CP101A PIN DIODE, SOT-23 1302 3991 0 TopCR301 48B61012 1N4742A ZENER DIODE, 12V 1W DL-41 MELF 991 604 90 TopCR302 48AA01SA DIODE, 1A, 50V, SMT, D0214AC CASE 1154 630 90 TopCR303 48A1005B MMBD6100, DUAL DIODES, COM CATHODE, SOT2 363 431 90 TopCR304 48A100A3 MMBD2835, DUAL DIODES, COM ANODE, SOT-23 65 4089 0 TopCR305 48A1005C MMBD7000, DUAL DIODES IN SERIES, SOT-23 626 2802 0 BottomCR306 48A1005C MMBD7000, DUAL DIODES IN SERIES, SOT-23 449 2956 90 BottomCR307 48AA01SA DIODE, 1A, 50V, SMT, D0214AC CASE 1290 630 90 TopCR401 48A1005C MMBD7000, DUAL DIODES IN SERIES, SOT-23 695 1808 90 TopCR402 48C1004E MMBV-105G DIODE VVC, SOT-23 1147 1115 180 TopCR403 48C1004G MMBV-2101L DIODE VVC SOT-23 1119 1400 180 TopCR404 48A1004D MMBV3401 PIN/UHF DIODE SOT-23 1552 1239 270 Top
44SST-444 SCHEMATIC REFERENCE PARTS LISTRef Ritron PN Description X Y Theta LocFUSEF301 06000040 WIRE; #40AWG TINNED BUS (INCHES) 754 603 270 BottomINTEGRATED CIRCUITSIC101 31030003 MC3371D SUBSYSTEM IC, SO-16 314 1158 270 BottomIC301 314G0301 MCU, 28 PIN, SOIC, SST/JMX 4-SERIES v01 992 2546 0 BottomIC302 31210005 EEPROM, 512X8, 24C04 989 2501 180 TopIC303 310K0004 LMV324MT RAIL TO RAIL QUAD OP AMP 474 2442 180 TopIC304 311K0003 SWITCH,ANALOG,TRIPLE SPDT,4053,TSSOP-16 241 2683 0 TopIC305 310K0003 LMV358MM DUAL OP AMP, GP LV R/R TSSOP 404 3120 0 TopIC306 310K0001 DS1806E 6 PROG POTS 10K OHM 20-PIN TSSOP 242 2185 0 TopIC307 31010004 LM386MX-1 AUDIO AMP SO-8 1331 567 90 BottomIC308 310K0002 MAX7410 5TH ORDER SW CAP BUTTERWORTH LPF 407 2935 0 TopIC309 310E0002 REGULATOR,LDO,LP2980,5V,W ENABLE,SOT-25 162 504 0 TopIC401 313K0004 SYNTHESIZER TSSOP MC145192 891 1265 180 TopJACKSJ301 02100001 2.5MM PC-MT JACK; ANT-CHGR 1178 4668 0 TopJ303 02100053 3.5MM STEREO JACK; PANEL MOUNT 1560 4646 0 TopINDUCTORSL101 01850201 1.5T SW COIL W/5MM SHIELD & ALUM CORE 721 4291 90 TopL102 18110151 CHIP INDUCTOR .15uhy 629 3722 270 TopL103 01850201 1.5T SW COIL W/5MM SHIELD & ALUM CORE 484 4291 270 TopL104 01850201 1.5T SW COIL W/5MM SHIELD & ALUM CORE 204 4292 270 TopL105 18433103 3T AIRCOIL, SMT, 8.0nH, .120 X .145 332 3901 180 TopL106 18110102 CHIP INDUCTOR 1.0uhy 280 3474 0 TopL107 18433101 1T AIRCOIL, SMT 2.5nH, .120 X .145 480 3492 180 TopL108 18110681 CHIP INDUCTOR .68uhy 51 1648 180 BottomL201 18414104 4.5T AIRCOIL #24AWG .0625” ID RHH SMT 929 3459 270 TopL202 18110150 INDUCTOR, CHIP, 15nH 1454 2281 180 TopL203 18414104 4.5T AIRCOIL #24AWG .0625"ID RHH SMT 1695 3948 90 TopL204 18414104 4.5T AIRCOIL #24AWG .0625"ID RHH SMT 1479 3945 180 TopL205 18110102 CHIP INDUCTOR 1.0uhy 1230 3667 0 TopL206 18414105 5.5T AIRCOIL #24AWG .0625"ID RHH SMT 1093 3979 90 TopL207 18433102 2T AIRCOIL SMT 5.0nH .120 X .145 932 4343 0 TopL401 18433209 9T AIRCOIL, SMT, 9.85 nH, .159 X .056 1376 1418 270 TopL402 18414109 9.5T AIRCOIL #24AWG .0625"ID RHH SMT 1352 118 0 TopL403 18110820 INDUCTOR, CHIP 82nH 1548 109 270 TopL404 18110101 CHIP INDUCTOR 0.1uhy 1187 966 270 TopL405 18110101 CHIP INDUCTOR 0.1uhy 753 1485 0 TopMICROPHONEM301 05500037 MICROPHONE; ELECTRET, MINIATURE 0 0 0 BottomCONNECTORSP201 25500700 CONTACT, PCB MNT, ANTENNA,SST 896 4550 90 TopP302 21310021 HEADER, 2 PIN SIDE ENTRY SHROUDED 754 737 0 TopTRANSISTORSQ101 4801002A MMBT3906 PNP, SOT23 675 3405 270 TopQ102 482100V0 TRANSISTOR, NPN, UHF, SOT-23, PBR-941 734 3828 0 TopQ103 4841006U MMBFJ309LT1, N-CHAN, RF, SOT23 340 3639 270 TopQ104 4821003B MMBT918LT1 VHF SOT23 (3B) 270 3548 0 Bottom
45SST-444 SCHEMATIC REFERENCE PARTS LISTRef Ritron PN Description X Y Theta LocQ105 4821003B MMBT918LT1 VHF SOT23 (3B) 38 1374 180 BottomQ201 4801002A MMBT3906 PNP, SOT23 908 3268 90 BottomQ202 4801001Q MMBT5088 NPN, SOT-23 766 3268 270 BottomQ203 04801503 M68710H 2W RF MODULE 450-470 MHz 6.0V 1819 2710 90 TopQ204 482100V0 TRANSISTOR, NPN, UHF, SOT-23, PBR-941 1603 2274 270 TopQ301 48010R02 MUN2211T1, NPN, INT 10K/10K BIAS, "8A", 1133 2987 90 BottomQ302 4801002A MMBT3906 PNP, SOT23 1094 3124 90 BottomQ303 4801001Q MMBT5088 NPN, SOT-23 583 519 0 TopQ304 480100DH BCW68GLT1 .8AMP PNP SOT-23 445 668 0 TopQ306 4801002A MMBT3906 PNP, SOT23 1222 2259 90 TopQ307 4801001Q MMBT5088 NPN, SOT-23 964 615 0 BottomQ308 480100DH BCW68GLT1 .8AMP PNP SOT-23 1162 712 0 BottomQ401 482100V0 TRANSISTOR, NPN, UHF, SOT-23, PBR-941 1470 1919 270 TopQ402 482100V0 TRANSISTOR, NPN, UHF, SOT-23, PBR-941 1289 1920 270 TopQ403 482100V0 TRANSISTOR, NPN, UHF, SOT-23, PBR-941 1460 1714 270 TopQ404 4801001Q MMBT5088 NPN, SOT-23 837 1766 270 TopQ405 4801006A MUN2111T1, PNP, INT 10K/10K BIAS, SC-59 1634 1376 270 TopQ406 48010R02 MUN2211T1, NPN, INT 10K/10K BIAS, "8A", 1691 1234 0 TopRESISTORSR101 47180103 10K OHM, RESISTOR, CHIP, 0402,1/16W,5% 579 3344 90 TopR102 47180103 10K OHM, RESISTOR, CHIP, 0402,1/16W,5% 734 3581 180 TopR103 47180102 1K OHM RESISTOR, CHIP,0402, 1/16W,5% 774 3716 270 TopR104 47180392 3.9K OHM RESISTOR, CHIP, 0402, 1/16W, 5% 829 3810 270 TopR105 47180561 560 OHM RESISTOR, CHIP, 0402, 1/16W, 5% 714 3519 270 TopR106 47180152 1.5K OHM RESISTOR, CHIP, 0402, 1/16W,5% 475 3610 270 TopR107 47180152 1.5K OHM RESISTOR, CHIP, 0402, 1/16W,5% 388 3484 180 BottomR108 47180223 22K OHM RESISTOR, CHIP, 0402, 1/16W, 5% 251 3450 180 BottomR109 47180101 100 OHM RESISTOR, CHIP, 0402,1/16W,5% 167 3450 180 BottomR110 47180154 150K OHM RESISTOR, CHIP, 0402, 1/16W,5% 411 946 270 BottomR111 47180122 1.2K OHM RESISTOR, CHIP, 0402, 1/16W,5% 529 904 270 BottomR112 47180224 220K OHM RESISTOR, CHIP, 0402, 1/16W, 5% 349 966 180 BottomR113 47180123 12K OHM RESISTOR, CHIP, 0402, 1/16W,5% 489 946 90 BottomR114 47180152 1.5K OHM RESISTOR, CHIP, 0402, 1/16W,5% 551 966 0 BottomR115 47180104 100K OHM, RESISTOR, CHIP, 0402,1/16W,5% 161 2174 270 BottomR116 47180103 10K OHM, RESISTOR, CHIP, 0402,1/16W,5% 161 2089 90 BottomR117 47180393 39K OHM RESISTOR, CHIP, 0402, 1/16W, 5% 117 1676 90 TopR118 47180103 10K OHM, RESISTOR, CHIP, 0402,1/16W,5% 79 1533 90 BottomR119 47180102 1K OHM RESISTOR, CHIP,0402, 1/16W,5% 59 1470 180 BottomR120 47180681 680 OHM RESISTOR, CHIP, 0402, 1/16W, 5% 78 1635 90 TopR201 47180103 10K OHM, RESISTOR, CHIP, 0402,1/16W,5% 790 3384 90 BottomR202 47180471 470 OHM RESISTOR, CHIP, 0402, 1/6W, 5% 669 3248 270 BottomR203 47180181 180 OHM RESISTOR, CHIP, 0402, 1/16W, 5% 908 3151 90 BottomR204 47100270 27 OHM 0805 CHIP RESISTOR 1796 2211 270 TopR205 47180822 8.2K OHM RESISTOR, CHIP, 0402, 1/16W, 5% 1555 2244 0 BottomR206 47180182 1.8K OHM RESISTOR, CHIP, 0402, 1/16W,5% 1618 2264 270 BottomR207 47180181 180 OHM RESISTOR, CHIP, 0402, 1/16W, 5% 1184 3549 270 TopR208 47180102 1K OHM RESISTOR, CHIP,0402, 1/16W,5% 879 4148 90 TopR301 47180103 10K OHM, RESISTOR, CHIP, 0402,1/16W,5% 536 686 90 TopR302 47100471 470 OHM 0805 CHIP RES. 475 479 270 TopR303 47180104 100K OHM, RESISTOR, CHIP, 0402,1/16W,5% 325 546 90 TopR304 47180102 1K OHM RESISTOR, CHIP,0402, 1/16W,5% 623 639 270 TopR305 47180104 100K OHM, RESISTOR, CHIP, 0402,1/16W,5% 402 547 270 TopR306 47180103 10K OHM, RESISTOR, CHIP, 0402,1/16W,5% 535 1867 90 BottomR307 47180103 10K OHM, RESISTOR, CHIP, 0402,1/16W,5% 995 3143 90 BottomR308 47180103 10K OHM, RESISTOR, CHIP, 0402,1/16W,5% 1127 3328 180 BottomR309 47180103 10K OHM, RESISTOR, CHIP, 0402,1/16W,5% 1257 2891 270 BottomR310 47180104 100K OHM, RESISTOR, CHIP, 0402,1/16W,5% 704 2191 0 BottomR311 47180104 100K OHM, RESISTOR, CHIP, 0402,1/16W,5% 504 4622 270 TopR312 47180103 10K OHM, RESISTOR, CHIP, 0402,1/16W,5% 704 2230 0 Bottom
46SST-444 SCHEMATIC REFERENCE PARTS LISTRef Ritron PN Description X Y Theta LocR313 47180104 100K OHM, RESISTOR, CHIP, 0402,1/16W,5% 1184 2376 270 TopR314 47180472 4.7K OHM RESISTOR, CHIP, 0402, 1/16W, 5% 1260 2375 270 TopR315 47180102 1K OHM RESISTOR, CHIP,0402, 1/16W,5% 738 2841 90 BottomR316 47180103 10K OHM, RESISTOR, CHIP, 0402,1/16W,5% 761 2557 90 TopR317 47180103 10K OHM, RESISTOR, CHIP, 0402,1/16W,5% 800 2506 90 TopR318 47180104 100K OHM, RESISTOR, CHIP, 0402,1/16W,5% 704 2521 180 BottomR319 47180471 470 OHM RESISTOR, CHIP, 0402, 1/6W, 5% 737 2756 270 BottomR320 47180471 470 OHM RESISTOR, CHIP, 0402, 1/6W, 5% 698 2879 270 BottomR321 47180103 10K OHM, RESISTOR, CHIP, 0402,1/16W,5% 636 2899 0 BottomR322 47180393 39K OHM RESISTOR, CHIP, 0402, 1/16W, 5% 294 3070 270 BottomR323 47180823 82K OHM RESISTOR, CHIP, 0402, 1/16W, 5% 371 3070 270 BottomR324 47180224 220K OHM RESISTOR, CHIP, 0402, 1/16W, 5% 332 3070 270 BottomR325 47180104 100K OHM, RESISTOR, CHIP, 0402,1/16W,5% 416 3156 90 BottomR326 47180183 18K OHM RESISTOR, CHIP, 0402, 1/16W, 5% 585 2413 270 BottomR327 47180183 18K OHM RESISTOR, CHIP, 0402, 1/16W, 5% 624 2328 90 BottomR328 47180103 10K OHM, RESISTOR, CHIP, 0402,1/16W,5% 493 2774 270 BottomR329 47180153 15K OHM RESISTOR, CHIP, 0402, 1/16W,5% 168 2374 90 TopR330 47180100 10 OHM RESISTOR, CHIP,0402, 1/16W 5% 664 2369 90 TopR331 47180104 100K OHM, RESISTOR, CHIP, 0402,1/16W,5% 269 2396 0 TopR332 47180154 150K OHM RESISTOR, CHIP, 0402, 1/16W,5% 207 2501 90 TopR333 47180473 47K OHM RESISTOR, CHIP, 0402, 1/16W, 5% 246 2500 90 TopR334 47180273 27K OHM RESISTOR, CHIP, 0402, 1/16W, 5% 566 2588 90 TopR335 47180102 1K OHM RESISTOR, CHIP,0402, 1/16W,5% 60 2787 270 TopR336 47180104 100K OHM, RESISTOR, CHIP, 0402,1/16W,5% 23 2787 270 TopR337 47180103 10K OHM, RESISTOR, CHIP, 0402,1/16W,5% 532 3156 270 BottomR338 47180224 220K OHM RESISTOR, CHIP, 0402, 1/16W, 5% 397 3228 90 TopR339 47180394 390K OHM RESISTOR, CHIP, 0402, 1/6W, 5% 420 2347 270 BottomR340 47180104 100K OHM, RESISTOR, CHIP, 0402,1/16W,5% 340 2436 90 BottomR341 47180104 100K OHM, RESISTOR, CHIP, 0402,1/16W,5% 239 2455 0 BottomR342 47180184 180K OHM RESISTOR, CHIP, 0402, 1/16W, 5% 153 2376 180 BottomR343 47180473 47K OHM RESISTOR, CHIP, 0402, 1/16W, 5% 731 3133 0 BottomR344 47180104 100K OHM, RESISTOR, CHIP, 0402,1/16W,5% 67 2416 180 BottomR345 47180104 100K OHM, RESISTOR, CHIP, 0402,1/16W,5% 153 2455 180 BottomR346 47180102 1K OHM RESISTOR, CHIP,0402, 1/16W,5% 732 3094 180 TopR347 47180274 270K OHM RESISTOR, CHIP, 0402, 1/16W, 5% 568 2588 90 BottomR348 47180473 47K OHM RESISTOR, CHIP, 0402, 1/16W, 5% 529 2589 90 BottomR349 47180823 82K OHM RESISTOR, CHIP, 0402, 1/16W, 5% 29 2146 0 TopR350 47180564 560K OHM RESISTOR, CHIP, 0402, 1/16W, 5% 29 2198 0 TopR351 47180222 2.2K OHM RESISTOR, CHIP, 0402, 1/16W, 5% 431 2269 90 TopR352 47100475 4.7M OHM 0805 CHIP RESISTOR 44 2406 0 TopR353 47180103 10K OHM, RESISTOR, CHIP, 0402,1/16W,5% 453 2158 180 TopR354 47180102 1K OHM RESISTOR, CHIP,0402, 1/16W,5% 847 653 180 BottomR355 47180103 10K OHM, RESISTOR, CHIP, 0402,1/16W,5% 912 772 90 BottomR356 47180273 27K OHM RESISTOR, CHIP, 0402, 1/16W, 5% 1293 780 90 BottomR357 47180102 1K OHM RESISTOR, CHIP,0402, 1/16W,5% 1147 534 90 BottomR358 47180153 15K OHM RESISTOR, CHIP, 0402, 1/16W,5% 1187 534 90 BottomR359 47180100 10 OHM RESISTOR, CHIP,0402, 1/16W 5% 1482 773 270 BottomR401 47180221 220 OHM RESISTOR, CHIP, 0402, 1/16W, 5% 1517 2006 90 TopR402 47180101 100 OHM RESISTOR, CHIP, 0402,1/16W,5% 1640 1828 270 TopR403 47180272 2.7K OHM RESISTOR, CHIP, 0402, 1/16W, 5% 1450 2013 180 TopR404 47180102 1K OHM RESISTOR, CHIP,0402, 1/16W,5% 1452 1825 180 TopR405 47180101 100 OHM RESISTOR, CHIP, 0402,1/16W,5% 1153 1900 270 TopR406 47180272 2.7K OHM RESISTOR, CHIP, 0402, 1/16W, 5% 1193 1900 270 TopR407 47180470 47 OHM RESISTOR, CHIP, 0402, 1/16W, 5% 1086 1788 270 TopR408 47180470 47 OHM RESISTOR, CHIP, 0402, 1/16W, 5% 1067 1726 180 TopR409 47180271 270 OHM RESISTOR, CHIP, 0402, 1/16W, 5% 1636 1655 90 TopR410 47180153 15K OHM RESISTOR, CHIP, 0402, 1/16W,5% 1266 162 5180 TopR411 47180153 15K OHM RESISTOR, CHIP, 0402, 1/16W,5% 1363 1694 270 TopR412 47180102 1K OHM RESISTOR, CHIP,0402, 1/16W,5% 1271 1827 180 TopR413 47180472 4.7K OHM RESISTOR, CHIP, 0402, 1/16W, 5% 677 1903 0 TopR414 47180103 10K OHM, RESISTOR, CHIP, 0402,1/16W,5% 1634 1531 270 Top
47SST-444 SCHEMATIC REFERENCE PARTS LISTRef Ritron PN Description X Y Theta LocR415 47180102 1K OHM RESISTOR, CHIP,0402, 1/16W,5% 1641 1068 90 TopR416 47180104 100K OHM, RESISTOR, CHIP, 0402,1/16W,5% 1138 1576 0 TopR417 47180102 1K OHM RESISTOR, CHIP,0402, 1/16W,5% 938 937 90 TopR418 47180473 47K OHM RESISTOR, CHIP, 0402, 1/16W, 5% 938 1022 90 TopR419 47180822 8.2K OHM RESISTOR, CHIP, 0402, 1/16W, 5% 718 906 0 TopR420 47180103 10K OHM, RESISTOR, CHIP, 0402,1/16W,5% 718 946 180 TopR421 47180223 22K OHM RESISTOR, CHIP, 0402, 1/16W, 5% 1101 1303 0 TopR422 47180100 10 OHM RESISTOR, CHIP,0402, 1/16W 5% 894 1461 90 TopR423 47180474 470K OHM RESISTOR, 0402, 1/16W, 5% 850 1100 180 TopSPEAKERSP301 05500045 SPEAKER, 45MM, 1W, LOW PROFILE SST/RTX 0 0 0 BottomSWITCHESSW301 05100042 SWITCH SPST MOMENTARY MINI PC 260GM 268 4587 180 TopSW302 05100042 SWITCH SPST MOMENTARY MINI PC 260GM 788 4588 180 TopSW303 05100046 SWITCH, TACT LO PROFILE RT ANGLE 160gf 82 3097 270 TopSW304 05100046 SWITCH, TACT LO PROFILE RT ANGLE 160gf 82 3948 270 TopTRANSFORMERT101 05600018 455KHZ IF TRANSFORMER (5MM) 128 1822 180 TopCRYSTALY302 23050003 TCVCXO, 14.400 MHz, 1.5 PPM, VC=30 PPM/V 146 837 90 TopFILTERSYF101 02301403 43.650 MHz Crystal Filter +/-6.0KHz UM-1 44 3524 90 TopYF102 02301013 FILTER,CERAMIC,450KHz,+/-7.5KHz,6 POLE 249 1614 90 TopHARDWARE1750240B PCB, ML4 FR4 5UPM, .062 MIX, SST-44425602500 CRYSTAL SUPPORT, RUBBER PAD, SMALL/UM-106001021 #28 AWG STRANDED WIRE; RED (INCHES)06001023 #28 AWG STRANDED WIRE;GREEN INCHES06001026 #28 AWG STRANDED WIRE; BLACK INCHES06001029 #28 AWG STRANDED WIRE; BLUE INCHES25105500 SHIELD, SST-PLUS SYNTHESIZER25603000 FOAM, MOUNTING, SPEAKER,SST25603900 SPACER, MIC FOAM, SST25605700 MICROPHONE HOLDER, SST-PLUS25900700 ADHESIVE, MTG, MIC HOLDER26200800 HEATSINK, TOP, SST+26200900 HEATSINK, BOTTOM, SST+2811H401 SCREW #4-40 X .25 LG TRIM HEAD PHILLIPS
48SST-444 CASE ASSEMBLY PARTS LISTRef Ritron PN DescriptionMAIN CASE ASSEMBLY13250000 CASE W/INSERT, PLASTIC, SST BLACK13578000 DOOR, BATTERY, PLASTIC, SST 2-PC13588000 LATCH, BATTERY DOOR, PLASTIC SST 2-PC25106400 BATTERY DOOR HINGE RETAINER25201500 RETAINER, PLASTIC, PTT, SST25400600 BUSHING, THREADED, PLATED, ANTENNA SS25603300 GRILLE CLOTH, SPEAKER, SST25603400 DUAL JACK PLUG, RUBBER,SST25606200 HINGE, BATTERY DOOR, SST25800500 ACTUATOR, RUBBER,PTT,SST25800600 ACTUATOR, RUBBER, TACT, SST02802026 NUT; KNURLED; M4PO.5;/2.5MM JACK02802027 NUT; KNURLED; M6PO.5/3.5MM JACK28112401 SCREW 4-40 X 1/4" PHFLST28233G03 KNURLED NUT, ANTENNA, JMXCASE BOTTOM ASSEMBLY13564000 CASE, BOTTOM, PLASTIC, SST 2-PC2142D021 CONNECTOR, CABLE ASSEMBLY, 2-POS, SST+25400800 SPRING CONTACT, BATTERY, SST W/O TABSC25400900 CONTACT BATTERY SST-PLUS (POLARIZED)25604800 SPACER, PCB, FOAM, SST 2-PCCASE LABELS14220001 LABEL, CONTROLS, SST14222029 LABEL, NAMEPLATE, SST14290002 BLANK LABEL, .75" X .25" GLOSSY WHITE +14200037 LABEL SST/JMX MFG DATE CODE14200039 LABEL FCC SERIAL SST-450BELT CLIP25201600 BELT CLIP, PLASTIC, SST BLACK2811B600 SCREW 6-32 X 1/4" PHTRSTBATTERY PACK AND INSULATORBPS-6N-SC BATTERY,RECHG,7.2V NiCd,BLUE ,SST14230088 LABEL, BATTERY, BPS-6N-SC, SST25300600 INSULATOR, BATTERY, FIBRE, SST25606000 FOAM SUPPORT, BATTERY JMX SERIES25601600 BATTERY SHIM; ASSEMBLY ~X~ SERIESANTENNAAFS-450 ANTENNA UHF MOLDED, 450-470 REG LEN SSTPACKING MATERIALS14210004 LOW BATTERY NOTICE LABEL14312006 SHIPPING CARTON, CARDBOARD,SST14321002 FOAM INSERT, PACKING, SST/MINI14500008 MANUAL, OWNERS, JMX/SST14500016 USER MANUAL SST-44414540006 WARRANTY REGISTRATION CARD

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