Wulfsberg Electronics Division 3YH-NPX138 VHF/FM Transceiver User Manual EDT002
Wulfsberg Electronics Division VHF/FM Transceiver EDT002
Manual
Northern Airborne Technology Ltd.
1925 Kirschner Road
Kelowna, BC, Canada.
V1Y 4N7
Telephone (250) 763-2232
Facsimile (250) 762-3374
Issued on the authority of Northern Airborne Technology Ltd.
Copyright 2010
Installation and Operation Manual
NPX138N Series
Panel Mount FM Transceiver
SM41
ISSUE 4.01
Published on
August 1, 2012
NPX138N Series Panel Mount FM Transceiver
SM41 Installation and Operation Manual
Installation and Operation Manual Page ii
ENG-FORM: 820-0116.DOT
CONFIDENTIAL AND PROPRIETARY TO NORTHERN AIRBORNE TECHNOLOGY LTD.
IMPORTANT INFORMATION
FOR AVIONICS INSTALLATION FACILITIES
The NPX138N Series Panel Mount FM Transceivers are supplied without TSO
certification, as no such standard presently exists for airborne VHF-FM radio
transceivers. This equipment provides what is considered as “supplemental”
communications, and can be installed in an aircraft on a “Non interference” basis.
Installation should be performed using standard procedures applicable to aircraft radio
installation, to ensure that the newly installed equipment does not interfere with any other
equipment in the aircraft.
This device complies with Part 15 of the FCC Rules. Operation is subject to the condition
that this device does not cause harmful interference
NPX138N Series Panel Mount FM Transceiver
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ENG-FORM: 820-0116.DOT
CONFIDENTIAL AND PROPRIETARY TO NORTHERN AIRBORNE TECHNOLOGY LTD.
Prepared By: Checked By: Certification: Approved By:
The status of this installation and operation manual is controlled by issue shown on the title page. The
status of each section is controlled by revision shown in the footer of each page. All revisions affecting
sections of this manual have been incorporated into the latest issue.
IMPORTANT NOTICE
Chelton Avionics Inc. doing business as Wulfsburg
Electronics Inc. will be responsible for full distribution and
revisions of ICA’s (Instructions for Continued
Airworthiness).
ISSUE/REVISION RECORD
Manual Issue
Number Section
Revision Number Revision Description Issue Date
4.01 Section 1 Rev: 1.00
Section 2 Rev: 1.00
Section 3 Rev: 1.00
Rewritten in latest format Aug 17, 2010
4.00 N/A - Nov 10, 2003
NPX138N Series Panel Mount FM Transceiver
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CONFIDENTIAL AND PROPRIETARY TO NORTHERN AIRBORNE TECHNOLOGY LTD.
Table of Contents
Section Title Page
1. Description
1.1 Introduction 1-1
1.2 Product Description 1-1
1.3 Design Features 1-1
1.4 Specifications 1-2
1.4.1 Electrical Specifications 1-2
1.4.2 Physical Specifications 1-3
1.4.3 Environmental Specifications 1-3
1.5 Unit Nomenclature 1-3
1.5.1 Narrowband Capability 1-4
1.5.2 Lighting Power 1-4
1.5.3 Special Options 1-4
1.5.4 Voice-Inversion Encryption 1-4
2. Installation
2.1 Introduction 2-1
2.2 Unpacking and Inspection 2-1
2.2.1 Warranty 2-1
2.3 Continued Airworthiness 2-1
2.4 Installation Procedures 2-1
2.4.1 Warnings 2-2
2.4.2 Cautions 2-2
2.4.3 Notes 2-2
2.4.4 Cabling and Wiring 2-2
2.4.5 Antennas 2-3
2.4.6 Mechanical Mounting 2-3
2.4.7 Post-Installation Checks 2-4
2.4.8 Post Installation EMI Test 2-5
2.5 Installation Drawings 2-5
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Section Title Page
3. Operation
3.1 Introduction 3-1
3.2 General Information 3-1
3.3 Controls and Indicators 3-1
3.4 Initial Operation 3-2
3.4.1 Power-up Help 3-2
3.4.2 Initial Operating Display 3-2
3.5 Display 3-3
3.6 Function Controls 3-3
3.6.1 Main RX (Receive) Volume Control 3-4
3.6.2 RX/TX Status Indicator 3-4
3.6.3 Scan/Guard TX Switch 3-4
3.6.4 Guard Controls 3-4
3.7 General Controls — Normal Operating Mode 3-5
3.7.1 Channel Switch 3-5
3.7.2 Brightness Switch 3-6
3.7.3 Squelch Pushbutton 3-6
3.8 Channel Display 3-6
3.8.1 ID Display Line 3-6
3.8.2 RX Display Line 3-7
3.8.3 TX Display Line 3-7
3.9 Channel Editing 3-8
3.9.1 SELECT Switch 3-8
3.9.2 NEXT Switch 3-9
3.9.3 EDIT Switch 3-9
3.9.4 HELP Switch 3-9
3.10 Status Editing 3-10
3.10.1 NEXT and SELECT Switch Use 3-10
3.10.2 Status Edit Features 3-11
3.11 Tones 3-12
3.11.1 General 3-12
3.11.2 Tone Display and Selection 3-12
3.11.3 Turning Tones On and Off 3-14
3.12 Scanning 3-14
3.12.1 General 3-14
3.12.2 Scan Operation 3-15
3.12.3 Scan Modes 3-15
3.13 Wideband/Narrowband Operation 3-16
3.13.1 Editing Wideband/Narrowband Flag 3-16
3.14 Configuration Mode 3-17
3.14.1 Using Configuration Mode 3-17
3.14.2 Configuration Option Table 3-18
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Section 1 Description
1.1 Introduction
Information in this section consists of product description, design features and specifications for the
NPX138N Series Panel Mount FM transceiver, serial number 1238 and above. All derivative product
information will be contained in the applicable manual supplement, which may be obtained from Northern
Airborne Technology Ltd. as required.
Review all notes, warnings and cautions.
1.2 Product Description
The NPX138N Series incorporates Northern Airborne Technology Ltd’s proven user-friendly operating
system with on-line help, making it easy to program and use. The small size makes this radio ideal for
airframes where size and weight are a factor.
The NPX138N Series panel mount FM transceiver is a stand-alone radio designed for the single mission
user. It provides all the features needed to satisfy FM communications within the VHF-FM high band.
1.3 Design Features
The NPX138N Series covers a frequency range of 138.000 MHz to 173.995 MHz in 5.0/6.25 kHz
increments. Each of the 100 available channels can include a receive frequency and CTCSS tone;
transmit frequency and CTCSS tone, and an alpha/numeric identifier.
A SCAN function allows scanning of selected channels. Transmit power of either 1 watt or 10 watts is
selectable from the front of the NPX138N. Simplex and semi-duplex operations are available. An optional
guard receiver is available with some models.
DTMF encoding and direct keyboard entry can be effected by the use of the DTE12, an accessory
available from Northern Airborne Technology Ltd.
Conveniently located beside the display are separate main volume, guard volume and transmit select
switches. Easily identified along the bottom of the front panel are squelch test, channel up/down and
display brightness controls. The aircraft dimmer buss provides control for the panel lighting.
Depending on model selected the NPX138N Series can provide wideband (± 5.0 kHz Rated System
Deviation) and/or narrowband (± 2.5 kHz Rated System Deviation) by channel. Compensation circuitry
ensures that the average receive audio level remains constant when the mode changes.
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1.4 Specifications
1.4.1 Electrical Specifications
Input power 28 Vdc nominal
Current consumption 0.5 A receive/2.0 A transmit (typical)
0.8 A receive/3.0 A transmit (max.)
Panel lighting 28 Vdc, 14 Vdc or 5 Vdc dependent on model
Sidetone output 25 mW @ 600 Ω, adjustable.
Microphone Amplified Dynamic or equivalent, 150 Ω
balanced/unbalanced
Frequency range 138.000 MHz to 173.995 MHz
Tone capability 38 standard CTCSS tones
Operating mode simplex or semi-duplex
1.4.1.1 Receiver
Channel increments 5 kHz/6.25 kHz
Audio output 100 mW @ 600 Ω Balanced/Unbalanced
Sensitivity
Main 0.5 μV max. @ 12 dB SINAD
Guard 0.5 μV max. @ 12 dB SINAD
Spurious response rejection 70 dB
Adjacent channel rejection
Wideband 70 dB min. @ ± 25 kHz
Narrowband 60 dB min. @ ± 12.5 kHz
Intermodulation rejection 70 dB
Hum and Noise ratio
Unsquelched >50 dB
Squelched <-80 dBw
Distortion <4% @ rated output
1.4.1.2 Transmitter
RF power output 1 W/10 W Selectable
RF input/output impedance 50 Ω nominal
Rated System Deviation
Wideband ± 5.0 kHz max, limited
Narrowband ± 2.5 kHz max, limited
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Microphone Audio Sensitivity 100 mVrms into 150 Ω for 60% of rated system deviation
Conducted spurious emissions
High power -64 dBc
Low power -55 dBc
Carrier frequency stability ±0.0003 %
FM hum and noise ratio >40 dB
AM hum and noise ratio >35 dB
Distortion <4 %
1.4.2 Physical Specifications
Height 1.88 inches (47.6 mm)
Overall depth 8.64 inches (219.5 mm)
Depth behind panel 7.66 inches (194.6 mm)
Width 5.75 inches (146.1 mm)
Weight 3.0 lbs. (1.4 kg)
Mounting Standard Dzus mounting (4 fasteners)
Connector type 25 pin D-subminiature male (pins)
Antenna connector BNC female
1.4.3 Environmental Specifications
Operating temperature -30 C to +60 C
Altitude 25,000 feet
Humidity 95%
Vibration DO-160C Cat. M
1.5 Unit Nomenclature
Variants of the NPX138N series radios are identified as follows:
Narrowband Capability
NPX138 N - 000
Special Options
Lighting Power
Encryption
ENG-FORM: 800-0116.DOT
CONFIDENTIAL AND PROPRIETARY TO NORTHERN AIRBORNE TECHNOLOGY LTD.
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1.5.1 Narrowband Capability {tc "1.6.1 Narrowband Capability
"}
The letter N after the NPX138 designation indicates the capability for narrowband selection in addition to
wideband. If this part of the name is blank, the unit has wideband capabilities only.
NPX138 N - 000
N = Wideband and Narrowband modulation
Blank = Wideband modulation only
1.5.2 Lighting Power {tc "1.6.2 Options "}
The digit in the first position of the unit suffix indicates the lighting power used.
NPX138 N - 000
0 = 28 Vdc Lighting
1 = 14 Vdc Lighting
2 = 28 Vdc NVG NVIS A Compliant
5 = 5 Vdc Lighting
7 = 28 Vdc NVG Compatible Lighting
8 = 14 Vdc NVG Compatible Lighting
9 = 5 Vdc NVG Compatible Lighting
1.5.3 Special Options
The digit in the second position of the unit suffix indicates any special options installed.
NPX138 N - 000
0 = No Special options installed
5 = USFS Standard Guard
6 = Custom Guard - consult factory for details
7 = Synthesized Guard
Other = Special options installed - consult factory for details
1.5.4 Voice-Inversion Encryption
The digit in the third position of the unit suffix indicates whether voice inversion encryption is installed.
NPX138 N - 000
0 = No Encryption
1 = Encryption
Section 1 ends
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Section 2 Installation
2.1 Introduction
Information in this section consists of unpacking and inspection procedures, installation procedures,
post-installation checks and installation drawings for the NPX138N Series Panel Mount FM Transceiver.
Review all notes, warnings and cautions.
2.2 Unpacking and Inspection
Unpack the equipment carefully and locate the warranty card. Inspect the unit visually for damage due to
shipping and report all such claims immediately to the carrier involved. Check that all items listed below
are present before proceeding and report any shortage immediately to your supplier:
- Warranty Card
- Operators Manual
- Certificate of Conformity or Release Certification
2.2.1 Warranty
All Northern Airborne Technology Ltd. products are warranted for 2 years from date of installation by an
authorized Northern Airborne Technology Ltd. dealer, to be free of defects in workmanship or
performance. This warranty covers all materials and labour, but is exclusive of any transport to deliver the
defective unit to and from Northern Airborne Technology Ltd. or its designated warranty repair center, or
any labour to remove or re-install the defective unit in the aircraft. Contact Northern Airborne Technology
Ltd. for any questions regarding this warranty, its applicability to your units and/or for return authorization.
Northern Airborne Technology Ltd. is the final arbitrator concerning warranty administration. Units which
have been physically damaged, burned, immersed in water or otherwise abused beyond the scope of
normal use will not be considered for warranty. WARRANTY IS VOID UNLESS THE PRODUCT IS
INSTALLED BY AN AUTHORIZED NORTHERN AIRBORNE TECHNOLOGY LTD. DEALER. Product
for which a warranty card is not returned shall be warranted from date of manufacture.
2.3 Continued Airworthiness
Maintenance of the NPX138N Panel Mount FM Transceiver is ‘on condition’ only. Periodic maintenance
of these products is not required.
2.4 Installation Procedures
Installation Notice
This product must be installed in accordance with the installation instructions provided in the latest issue
of this Installation and Operation Manual. Check the Publication Index at www.northernairborne.com for
the issue status of the manual. The latest issue of the manual may be downloaded from the same
website. All risk associated with installation of this product contrary to these instructions shall be the
responsibility of the installing agency.
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CONFIDENTIAL AND PROPRIETARY TO NORTHERN AIRBORNE TECHNOLOGY LTD.
2.4.1 Warnings
WARNING:
High volume settings can cause hearing damage.
Set the headset volume control to the minimum setting prior to
conducting tests, and slowly increase the volume to a comfortable
listening level.
2.4.2 Cautions
CAUTION:
Do not bundle any lines from this unit with transmitter coax lines. Do not
bundle any logic, audio, or DC power lines from this unit with 400 Hz synchro
wiring or AC power lines. Do not position this unit next to any device with a
strong alternating magnetic field such as an inverter or significant interference
to operation will result. In all installations, use shielded cable exactly as
shown and ground as indicated. Significant problems may result if these
guidelines are not followed.
All audio installations can be severely degraded by incorrect wiring and
shielding, and may result in much higher cross-talk, hum, and ground-loop
interference. This should be considered when audio wiring to and from the
radio installation is performed.
2.4.3 Notes
The case of the NPX138N must be electrically grounded for maximum resistance to low frequency
interference. A pin on the connector (Chassis ground) is provided and must be connected by a short wire
to a clean ground, not jumpered to the power ground wire connection.
Refer to the aircraft structural repair manual and maintenance manual for instructions and information
pertinent to this installation.
2.4.4 Cabling and Wiring
All wire shall be selected in accordance with the original aircraft manufacturer's Maintenance Instructions
or AC43.13-1B Change 1, Paragraphs 11-76 through 11-78. Unshielded wire types shall qualify to
MIL-W-22759 as specified in AC43.13-1B Change 1, Paragraphs 11-85, 11-86, and listed in Table 11-11.
For shielded wire applications, use Tefzel MIL-C-27500 shielded wire with solder sleeves (for shield
terminations) to make the most compact and easily terminated interconnect. Follow the interconnect
drawing in Section 2.5 as required.
Coaxial cable shall be selected in accordance with MIL-C-17 unless otherwise specified. Do not use coax
cable with PVC insulation. Teflon dielectric cable is encouraged at or above VHF frequencies or where
cable runs exceed 8 feet. Note that at VHF frequencies, cables losses due to long cable runs and tight
bends may reduce the ERP (Effective Radiated Power) by greater than 50%.
Allow 3" from the end of the shielded wiring to the shield termination to allow the connector hood to be
easily installed. Refer to the interconnect drawing in Section 2.5 for shield termination details. Note that
the hood is a "clamshell" hood, and is installed after the wiring is complete. Aircraft harnessing shall
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permit the unit to be removed from the panel for easy access to all side adjustments. Do NOT mount the
unit until all adjustments have been performed.
Maintain wire segregation and route wiring in accordance with the original aircraft manufacturers
Maintenance Instructions. Coaxial cables shall be routed separately from existing wire bundles in the
aircraft to minimize electromagnetic coupling effects.
Unless otherwise noted, all wiring shall be a minimum of 22 AWG, except power and ground lines, which
shall be a minimum of 20 AWG. Reference the Interconnect drawing for additional specifications. Check
that the ground connection is clean and well secured, and that it shares no path with any electrically noisy
aircraft accessories such as blowers, turn and bank instruments or similar loads. Power to this unit must
be supplied from a separate circuit breaker or fuse (fast blow), and not attached to any other circuit
breaker without additional protection. Verify that the selected circuit breaker size and wire gauge are
adequate for the installation using the techniques specified in AC43.13-1B Change 1, Paragraphs 11-47
through 11-51 and 11-66 through 11-69.
2.4.5 Antennas
Correct antenna placement and mounting is critical in order to achieve the best possible performance. In
general, keep all antennas as widely separated as possible and clear of any large airframe obstructions.
Installation of the antenna should be in accordance with the original aircraft manufacturer’s instructions
for continued airworthiness or AC 43.13-1B Change 1, chapter 11, section 15 and AC 43.13-2A chapter 3.
If possible, the antenna should be located a minimum of 12 ft from aircraft navigation receiver antennas
and a minimum of 4 feet from aircraft communications and ELT antennas. Be careful not to choose
separations that closely approximate ¼, ½ or whole-number multiples of the navigation or
communications system wavelength.
Note: Avoid any placement that puts antennas of like frequencies close together.
Bottom mounted antennas will perform best in flight, but poorest on the ground during testing. Antennas
may be severely degraded by 'masking' effects of the fuselage or stabilizers, and generally give best
performance when bottom mounted.
To reduce interference from rotor modulation and other undesirable stimuli, any blade or whip antenna
must be surrounded by a ground plane surface (metallic, grounded material) with a radius equal to or
greater than the height of the antenna. Under the same conditions, the antenna is also much less likely to
cause interference to other aircraft systems (e.g. coupling into audio system, fluctuations in instrumentation,
etc.). Poor grounding will result in severe reflected power and high levels of RFI throughout the airframe.
Avoid antenna locations that will become fouled with oil, water, fuel or dirt, as this will degrade
performance. Roof mounts (in close proximity to rotor blades) are permissible.
2.4.6 Mechanical Mounting
Installation of the transceiver should be in accordance with the original aircraft manufacturer’s instructions
for continued airworthiness or AC 43.13-1B Change 1, chapter 7, sections 2 to 7 and AC 43.13-2A, chapter
2. Pr 35 Dzus rail or equivalent may be used.
Mounting the NPX138N requires a Dzus rail assembly with an opening width of 127 mm (5 inches) and a
front clearance width of 146.1 mm (5.75 inches). Height requirement is 47.6 mm (1.875 inches). Refer to
the mounting drawings and unit mechanical specifications to determine proper clearance dimensions. Be
sure that adequate clearance is allowed for the cable connections to each unit.
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2.4.7 Post-Installation Checks
2.4.7.1 Voltage/resistance checks
Do not attach the NPX138N until the following conditions are met.
Check the following:
a) P101 pins <12> and <13> for +28 Vdc relative to ground.
b) P101 pins <22>, <23>, <24> and <25> for continuity to ground (below 0.5 Ω).
c) Light voltage as listed in the table below.
P101 Pin # Voltage
28 Volt Models 11 28 Vdc
14 Volt Models 10 14 Vdc
5 Volt Models 10 5 Vdc
Light Voltage
Ensure that the antenna is disconnected for the following test or erroneous readings may be
obtained.
d) Radio coax connector for continuity to the antenna coax connector (shield and center conductor),
and for open circuit from the center conductor to ground and open circuit from the center
conductor to the shield.
2.4.7.2 Power On Checks
a) Install the NPX138N and power up the ship’s systems. Turn on the radio. Check the operation of all
front panel controls. Adjust brightness and volume levels as required.
b) Check all transmit and receive functions. Ensure the RX/TX status indicator lights green when
the radio is keyed to transmit and amber when receiving.
c) Check the SCAN function.
Note: It may not be possible to hear the received audio if the tones do not match those set in
the radio. To avoid any confusion, tones should be set to OFF (via the status edit mode)
during scanning so that all channels will be heard.
d) Check the antenna feedline at the R/T with a through-line wattmeter and suitable frequency
elements to ensure correct antenna matching. Reflected power in excess of 25% represents a
serious problem, and should be investigated carefully, or serious RFI and system interference as
well as possible radio damage may result. A VSWR measurement over 3.0:1 represents a
significant loss in signal power to the antenna. Check that forward power is to specifications over
the frequency band of the radio.
Upon satisfactory completion of all performance checks, make all required log book entries, electrical
load, weight and balance amendments and other documentation as required by your local regulatory
agency before releasing the aircraft for service.
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2.4.8 Post Installation EMI Test
The purpose of this test is to identify any interference that the NPX138N may cause with existing aircraft
systems. The NPX138N should be tested in accordance with the Installation Approval Test Procedure
(see section 2.5), and the test results documented on the record sheets.
2.5 Installation Drawings
DOCUMENT REV. DESCRIPTION TYPE
NPX138\403-0 1.50 Panel Mount Radio Interconnect (2 sheets)
NPX138\405-0 1.20 Panel Mount Radio Connector Map
NPX138\634-0 1.10 Post Installation EMI Test Installation Approval Test Procedure
NPX138\905-0 1.50 Panel Mount Radio Faceplate
NPX138\922-0 1.21 Panel Mount Radio Mechanical Installation
Section 2 ends following the above documents
INSTALLATION APPROVAL
TEST PROCEDURE
NAT Part #: NPX138 Description: Panel Mount Radio
Document #: NPX138\634-0 Rev: 1.10
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CONFIDENTIAL AND PROPRIETARY TO NORTHERN AIRBORNE TECHNOLOGY LTD.
1. Post Installation EMI Test
The purpose of this test is to identify any interference that the NPX138 may cause with
existing aircraft systems.
2. Test Conditions
The NPX138 should be installed and function tested. The antenna VSWR should be
checked. A forward/reverse power check with an in-line wattmeter should show no
more than 10% reflected power. For the following tests, insure that the transmit power
is set to HI.
3. Methodology
Most of the EMI tests can be accomplished on the ground. In some cases, flight testing is
required or is easier. If the aircraft is approved for IFR operations, then it is mandatory
that interference between the NPX138 and the approach aids be checked in flight.
The GPS should be operational and navigating with at least the minimum compliment of
satellites. The VHF comm should be set to the frequencies indicated with the squelch open.
VOR/ILS/GS receivers should be set to the frequencies indicated and selected for display. If
possible, set up a VOR/ILS ramp test set on the frequencies indicated and adjust the output
until the flags are out of view. The transponder and encoder should be monitored with ramp
test equipment. If possible set the ADF to a nearby navigation station.
Modulate the NPX138 transmitter on the indicated frequencies for at least 20 seconds.
Observe the GPS for any degradation in satellite status or availability or flags. Listen for
any noise or detected audio signals on the VHF comm(s). Listen for any noise or
detected audio signals on the VOR/LOC receiver audio; look for any movement of flags
or needles on the VOR/LOC/GS navigation display(s).
List the power plant, fuel and other electric instruments in the chart provided and note
any anomalies that occur while transmitting. Assess the results.
If the aircraft is equipped with an autopilot or a stability augmentation system, then test
fly the aircraft and verify that the operation of the NPX138 transceiver does not have
adverse effects on these systems. After checking for gross effects at a safe altitude, fly
an approach with each of the different navigation systems coupled to the autopilot (ILS,
GPS etc.) and look for any anomalies.
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4. Results
If the installed system passes all of the applicable EMI tests, then no further action is
required. If interference is observed, then the interference must be assessed against
the appropriate standards of airworthiness for the system in question. For example: it is
permissible for a VFR certified GPS to lose navigation capability while the NPX138 is
transmitting, providing that it recovers properly and promptly, but it is not permissible for
an IFR Approach certified GPS to be affected in the same way. A complete discussion
of all the standards of airworthiness to be applied in assessing EMI effects is beyond
the scope of this document.
5. Procedure
A. Operate the NPX138 transmitter on the following frequencies for at least 20 seconds.
Observe the GPS for any degradation in satellite status, or availability, or flags.
FREQUENCIES GPS #1 GPS #2
NPX138 PASS FAIL PASS FAIL
143.2187 MHz
143.2200 MHz
153.4500 MHz
157.5400 MHz
157.5437 MHz
NOTES:
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B. Determine if the image frequency for the VHF Comm falls within the range of the
NPX138 unit. If so, select a set of frequencies that will cause the NPX138 to be
set as close as possible to the image frequency. Any one of the many possible
sets will suffice. Record these values in the spaces provided in the following
chart. Modulate the NPX138 transmitter on the following frequencies for at least
20 seconds. Listen for any noise or detected audio signals on the VHF comm.
Example - Bendix/King KY 196A:
The first IF frequency is 11.4 MHz. The L.O. is above the received frequency
(high side injection), therefore the image frequency is 22.8 MHz above the
selected frequency. Set the KY 196A to 120.000 MHz and the NPX138 to
142.8000 MHz.
FREQUENCIES RESULTS
VHF #1 NPX138 PASS FAIL
135.975 138.0000
121.150 157.5000
131.250 157.5000
Image:
FREQUENCIES RESULTS
VHF #2 NPX138 PASS FAIL
135.975 138.0000
121.150 157.5000
131.250 157.5000
Image:
NOTES:
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C. Determine if the image frequency for the VOR/ILS Nav falls within the range of
the NPX138 unit. If so, select two sets of frequencies that will cause the NPX138
to be set as close as possible to the image frequency. Choose one set in the
localizer frequency range, and one in the VOR frequency range. Record these
values in the spaces provided in the following chart. Modulate the NPX138
transmitter on the following frequencies for at least 20 seconds. Listen for any noise or
detected audio signals on the receiver audio; look for any movement of flags or needles
on the navigation display.
FREQUENCIES RESULTS
VOR/ILS #1 NPX138 PASS FAIL
108.000 162.0000
108.100 162.1500
Image:
Image:
FREQUENCIES RESULTS
VOR/ILS #2 NPX138 PASS FAIL
108.000 162.0000
108.100 162.1500
Image:
Image:
NOTES:
NPX138 Installation Approval Test Procedure
Rev. 1.10 Apr 19, 2004 Page 5 of 7
E NG-FORM: 634-0100.DOT
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D. Modulate the NPX138 transmitter on the following frequencies for at least 20
seconds. Look for any movement of flags or needles on the navigation display.
FREQUENCIES RESULTS
G/S #1 NPX138 PASS FAIL
334.7 (108.1) 167.3500
FREQUENCIES RESULTS
G/S #2 NPX138 PASS FAIL
334.7 (108.1) 167.3500
NOTES:
Note: For the following tests, select frequencies at the top, middle and bottom of the
range of the NPX138.
Frequency #1 ______________ Frequency #2 ______________
Frequency #3 ______________
E. At a safe altitude, engage the autopilot or stability augmentation system.
Modulate the NPX138 transmitter on the above frequencies for at least 20
seconds. Observe any effect on the autopilot or stability augmentation system.
Observations:
NPX138 Installation Approval Test Procedure
Rev. 1.10 Apr 19, 2004 Page 6 of 7
E NG-FORM: 634-0100.DOT
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F. Perform a coupled ILS approach to the aircraft's certified limits. Modulate the
NPX138 transmitter on the above frequencies for at least 20 seconds. Observe
any effect on the autopilot. Repeat for each different system such as ILS #2,
GPS, FMS etc.
Observations:
G. List the power plant, fuel and other electric instruments in the chart provided and
note any anomalies that occur while transmitting. Assess the results.
STEP SYSTEM PASS FAIL NOTES
1 Xponder & Encoder
2 ADF 1 & 2
3 VG
4 Compass
5 Directional Gyro
6 Oil Pressure
7 Fuel Pressure
8 Oil Temp
9 Amps
10 Bus Voltage
11 Fuel %
12 Ng
13 TOT
14 Torque %
15 Annunciators
16 Digital Clock
NPX138 Installation Approval Test Procedure
Rev. 1.10 Apr 19, 2004 Page 7 of 7
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STEP SYSTEM PASS FAIL NOTES
NOTES:
End of Installation Approval Test Procedure
NPX138N Series Panel Mount FM Transceiver
SM41 Installation and Operation Manual
Section 3 Rev: 1.00 Issue 4 Page 3-1
ENG-FORM: 806-0115.DOT
CONFIDENTIAL AND PROPRIETARY TO NORTHERN AIRBORNE TECHNOLOGY LTD.
Section 3 Operation
3.1 Introduction
Information in this section consists of functional and operational procedures for the NPX138N Panel
Mount FM Transceiver.
3.2 General Information
In addition to the general functions that are available on other FM radios, the NPX138N has several
features that extend its capability and make it easier to use. These features include alphanumeric
channel labelling, built-in operator help, scanning, optional guard receiver, and numerous others.
For ease of use and operability, Northern Airborne Technology Ltd uses the same control layout and
operating system in the NPX138N series of radios as it does in its popular Tac/Com family of radio control
heads.
In addition to this manual, there is a help function built into the radio comprehensive sufficient to address
most operational questions.
Many of the front panel controls have more than one function, dependent on the operating mode of the
radio. For this reason, they have multiple labels. When the radio is in ‘Normal’ mode (EDIT switch in the
center ‘Off’ position), use the top label and when the radio is in ‘Edit’ mode (either ‘CH’ or ‘ST’), use the
bottom label.
3.3 Controls and Indicators
In addition to the general functions that are available on other FM radios, the NPX138N has several
features that extend its capability and make it easier to use. These features include alphanumeric
channel labelling, built-in operator help, scanning, optional guard receiver, and numerous others.
For ease of use and operability, Northern Airborne Technology Ltd uses the same control layout and
operating system in the NPX138N series of radios as it does in its popular Tac/Com family of radio control
heads.
In addition to this manual, there is a help function built into the radio comprehensive enough to address
most operational questions.
Many of the front panel controls have more than one function, dependent on the operating mode of the
radio. For this reason, they have multiple labels. When the radio is in ‘Normal’ mode (EDIT switch in the
center ‘Off’ position), use the top label; and when the radio is in ‘Edit’ mode (either ‘CH’ or ‘ST’) use the
bottom label.
NPX138N Series Panel Mount FM Transceiver
SM41 Installation and Operation Manual
Section 3 Rev: 1.00 Issue 4 Page 3-2
3.4 Initial Operation{tc "1.4.2 Initial Operation"}
3.4.1 Power-up Help
Turn the NPX138N on by rotating the main volume control clockwise, away from the ‘Off’ detent position.
The software revision number will briefly display, followed by a screen presenting an option for use of the
on-line Help system, as shown below.
If the HELP button is pushed, the radio will present a tutorial on the operation of the radio. To advance
through the tutorial, press HELP after reading each screen. To exit this initial HELP function at any time,
move the NEXT switch momentarily left or right.
3.4.2 Initial Operating Display
If ‘Help’ is declined (by using the NEXT switch as directed), the radio will display a summary of the
installed functions and current settings (this feature can be disabled at installation for faster start-up).
The radio is then ready for normal operation.
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NPX138N Series Panel Mount FM Transceiver
SM41 Installation and Operation Manual
Section 3 Rev: 1.00 Issue 4 Page 3-3
3.5 Display{tc "1.4.3 Display"}
Channel
Info
Status
Info
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The diagram above shows a typical radio display in ‘Normal’ operating mode. The upper row of the
display contains information related to the currently selected channel. The specific information displayed
depends on the setting of the DISP (display) switch located in the bottom left hand corner of the front
panel. When it is in the ID position (as shown above), the display shows the channel identifier or name.
When it is in the RX or TX position, the display shows the respective receive or transmit information. See
section 3.8 for further details on the Channel Display.
Brightness Control
Channel Display Mode
The lower row of the display contains information related to specific radio functions. Normally, it shows
the settings for the power level and the CTCSS tones. However, entering the Status edit mode allows the
display of other function settings. See section 3.10 for further details on displaying and changing Status
information.
The BRIGHT switch controls the brightness of the display text. See section 3.7.2 for further details.
3.6 Function Controls{tc "1.4.4 Function Controls"}
The controls located to the right of the display are ‘Function’ controls. These controls access the radio
functions most often used. Access to all other functions is via the status lines (see section 3.10 for further
details on ‘Status Editing’).
RX/TX Status Indicator
Scan/Guard TX
Switch
Main RX Volume Control
Guard
Controls
NPX138N Series Panel Mount FM Transceiver
SM41 Installation and Operation Manual
Section 3 Rev: 1.00 Issue 4 Page 3-4
3.6.1 Main RX (Receive) Volume Control
Set this rotary control to the furthest counterclockwise position (past the ‘Off’ detent) to turn ‘off’ the radio.
Rotating it clockwise will turn ‘on’ the radio. To increase the volume of the main receiver, turn this knob
clockwise; to decrease the volume turn this knob counterclockwise.
3.6.2 RX/TX Status Indicator
Next to the main RX volume control is a bi-color LED indicator that displays the RX (Receive) status of
the main receiver and the TX (Transmit) status of the radio. When the radio is transmitting the LED will
light green. When the main receiver receives a signal, the LED will light amber. If the radio is idle (not
receiving or transmitting), the LED will be dark. The color-coding used for these functions corresponds to
standard aircraft FM radio conventions. It is worth noting that this is the reverse of standard vehicular
conventions so may confuse some emergency services staff familiar with land mobile equipment.
The receive indicator (amber) informs the operator that the channel is active with radio traffic of some
kind. A radio that is receiving may still not produce any audio if the tones present on the receive signal do
not match the tones set in the radio. See section 3.11 for further details on how CTCSS tones work.
3.6.3 Scan/Guard TX Switch
When this switch is in the SCAN position, the radio will begin scanning. See section 3.12 for further
details on scanning.
When this switch is in the GD TX position, all radio transmissions will be on the guard transmit frequency
instead of the transmit frequency of the current channel. The radio continues to receive on both the Guard
and Main receivers. This function only applies to radios with the guard receiver option installed. If not, the
radio will display ‘GD NOT INSTALLED’ on the upper line when the switch is set to the GD TX position.
Set this switch to the NORM position to disable scanning. All radio transmissions will use the transmit
frequency of the current channel.
3.6.4 Guard Controls
Guard RX Indicator
Guard RX Volume Control
Guard
Select
Switch
The guard controls are functional only in radios with the optional guard receiver installed.
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NPX138N Series Panel Mount FM Transceiver
SM41 Installation and Operation Manual
Section 3 Rev: 1.00 Issue 4 Page 3-5
The rotary knob independently sets the guard RX volume. In most models, there is no ‘Off’ detent
position. On most NPX138N models, even with the guard RX volume set completely counterclockwise,
the operator will still hear activity on the guard channel (at the preset minimum level).
The Guard Select switch (marked GD1/GD2 on the faceplate) selects the active guard channel. For
standard guard receiver modules (-x5x), the first guard channel (GD1) has a receive frequency of
168.625 MHz and the second guard channel (GD2) has a receive frequency of 167.950 MHz, as specified
by the USFS. Radios with custom guard receiver modules are available (-x6x). For radios with
synthesized guard modules (-x7x), the receive frequencies for both the GD1 and GD2 channels are
programmable via the front panel or serial load to any frequency in the range of 138.000 to 173.995 MHz
in 5.0/6.25 kHz increments. The transmit frequencies of the guard channels are programmable. The
Guard RX LED indicator lights amber when there is activity on the selected guard channel.
3.7 General Controls — Normal Operating Mode{tc "1.4.5 General
Controls — Normal Operating Mode"}
Channel Switch Brightness Switch Edit Switch Squelch Pushbutton
The General Controls are those labelled in the above diagram and affect the over-all operation of the
radio. The position of the EDIT switch determines the operating mode of the radio. The other three
controls (the two center-off momentary switches and the pushbutton) have dual functions, operating
differently depending upon the selected operating mode.
When the EDIT switch is in the center position (as shown), the radio is in ‘Normal’ operating mode and
the functions of the other switches are those of the upper label.
Lock the EDIT switch to either the left (CH) or right (ST) position, to set the radio in one of the two ‘EDIT’
modes. In both ‘EDIT’ modes, the functions of the other switches are those of the lower label. Engraved
panel lines tie related Edit functions together. See sections 3.9 and 3.10 for further details on editing.
3.7.1 Channel Switch
To scroll to the desired channel use the CHAN switch. Momentarily press it to the right ‘+’ to increment
by one channel and to the left ‘−’ to decrement by one channel. Holding the switch in either the left or
right position causes the radio to continue to change channels with increasing speed. This allows for
quick selection of any channel.
Note: Remote channel selection is possible with the installation of an external switch.
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NPX138N Series Panel Mount FM Transceiver
SM41 Installation and Operation Manual
Section 3 Rev: 1.00 Issue 4 Page 3-6
3.7.2 Brightness Switch
The BRIGHT switch controls the brightness of the radio display. Momentarily press it to the right ‘+’ to
increment the display brightness by one level and to the left ‘−’ to decrement by one level. There are
seven brightness levels from which to select. The radio will retain the display brightness information
when turned off, but on power up will limit brightness to a maximum of level five.
3.7.3 Squelch Pushbutton
Pressing the SQ (squelch) test button over-rides all squelch logic, and lets the radio’s unsquelched audio
receive signal pass to the aircraft’s audio system. The squelch test function is useful for monitoring
activity on the radio when tones prevent the squelch from opening, or to verify volume settings or radio
function.
3.8 Channel Display{tc "1.4.6 Channel Display"}
For each channel stored in the radio, there are three data lines; the ID line, the RX line, and the TX line.
Depending on the position of the DISP switch, one of these data lines will be shown on the top row of the
display. Regardless of which of the three is being displayed, the channel number will always show on the
far left hand side and RX/TX functions will be operational.
3.8.1 ID Display Line
The ID line includes the channel number, the channel label or name, the scan list flag, and the priority
scan channel flag. A typical ID display line might look like this:
01 FORESTRY sc p1
Channel Label Scan Flags
The label for each channel is an alphanumeric name that may be up to 10 characters long. The channel
name has no effect on radio operation, and is provided for operator convenience in identifying the
selected channel.
The scan list flag indicates whether or not the radio monitors the channel during scanning. The ‘sc’
character means that the channel is in the scan list. A dash ‘−’ indicates the channel is not in the scan list.
The ‘p1’ character means that the channel is the priority scan channel. A dash ‘−’ indicates the channel is
not selected as a priority channel.
If the radio is a NPX138N, there will also be a bandwidth flag displayed on the ID line. A typical
NPX138N ID line might look like this:
01 FORESTRY sc p1
Channel Label Bandwidth Scan Flags
The bandwidth flag indicates the current modulation acceptance and transmit deviation mode. A ‘ ’
character indicates that the channel is operating in wide-band (± 5.0 kHz Rated System Deviation) mode.
An ‘ ’ character indicates that the channel is operating in narrow-band (± 2.5 kHz Rated System Deviation)
mode (refer to section 3.13).
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NPX138N Series Panel Mount FM Transceiver
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Section 3 Rev: 1.00 Issue 4 Page 3-7
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CONFIDENTIAL AND PROPRIETARY TO NORTHERN AIRBORNE TECHNOLOGY LTD.
3.8.2 RX Display Line
The RX line includes the channel number, the receive frequency and the receive tone. A typical RX line
might look like this:
01 156.8750r 91
Channel RX Freq. RX Tone
The radio will receive incoming FM signals that have a carrier frequency equal to that of the receive
frequency of the displayed channel.
If the display shows the RX frequency as ¼¼¼i¼¼¼¼, it means the programmed frequency is invalid.
See section 3.9 for details on how to change it to a valid value. The small ‘r’ indicates that the data
displayed is ‘Receive’ data. If the radio is in ‘Simplex’ mode, an ‘s’ will replace the ‘r’. In ‘Simplex’ or
’Direct’ operation, the radio’s TX data matches the RX data. This permits talk-around operation on
repeaters. The programmed TX data remains in the radio, but is unused until the operator returns the
radio to duplex mode.
The last three positions (far right hand side) on the RX line display an optional CTCSS (sub-audible) tone
used for repeater or squelch control. The radio has several different methods by which to display the
tone. See section 3.11 for further details on tones.
3.8.3 TX Display Line
The TX line includes the channel number, the transmit frequency and the transmit tone. A typical TX line
might look like this:
01 156.8750t 91
Channel TX Freq. TX Tone
When the microphone is keyed, the radio will transmit an FM signal that has a carrier frequency equal to
that of the transmit frequency of the displayed channel.
If the display shows the TX frequency as ¼¼¼i¼¼¼¼, it means the programmed frequency is invalid.
See section 3.9 for details on how to change it to a valid value. The small ‘t’ indicates that the data
displayed is ‘Transmit’ data. If the radio is in Simplex mode, an ‘s’ will replace the ‘t’. In ‘Simplex’ or
‘Direct’ operation, the radio’s TX data matches the RX data. This permits talk-around operation on
repeaters. The programmed TX data remains in the radio, but is unused until the operator returns the
radio to duplex mode.
The last three positions (far right hand side) on the TX line display an optional CTCSS (sub-audible) tone
used for repeater or squelch control. The radio has several different methods by which to display the
tone. See section 3.11 for further details on tones.
NPX138N Series Panel Mount FM Transceiver
SM41 Installation and Operation Manual
Section 3 Rev: 1.00 Issue 4 Page 3-8
3.9 Channel Editing{tc "1.4.7 Channel Editing"}
Editing is the general term for changing any information stored in the NPX138N radio. There are two
basic types of editing, all selectable from the front panel of the radio. These are ‘Channel editing’ (CH)
and ‘Status editing’ (ST). The labels below the general controls (connected by lines) represent the
functions of those switches during editing.
As the name implies, the channel editing feature, when enabled, permits the operator to change channel
data. This data includes channel names, transmit and receive frequencies and tones, and list scan flags.
For models with synthesized guard modules (-x7x), the guard receive frequencies may be edited when
the SCAN/NORM/GD TX switch is in the GD TX position, and the radio is in the 'Channel Edit' mode.
For all other models, editing of guard receive frequencies is not possible.
Only those frequencies the radio recognizes as ‘valid’ are enterable, and only in the fractional multiples
allowed.
To edit channel information, use the DISP switch to select the required data line for editing (ID, RX or
TX), and then enter ‘Channel Edit’ mode.
To enter ‘Channel Edit’ mode, pull and lock the EDIT switch to the left (CH). The position or character to
be edited will blink. This blinking character (editing cursor) indicates the data selected for editing.
SELECT (Scroll Data) NEXT (move cursor) Channel Edit HELP
When channel editing of data is in progress, the radio suspends normal operation and the dual function
controls work as described in the following sections.
3.9.1 SELECT Switch
The SELECT switch steps the data entry up or down (+or −). The radio only permits a valid choice for
each position selected for editing. This is to aid operators in reducing entry mistakes, particularly when
busy with other flight procedures.
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NPX138N Series Panel Mount FM Transceiver
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Section 3 Rev: 1.00 Issue 4 Page 3-9
The selection choices string together as if in a circle, and the operator
moves through this circle with the SELECT switch. Depending on which
way the operator sets the SELECT switch (+ or −), the editor will move
around the circle in either direction.
When editing frequency, (TX or RX) the editor removes numbers from
this circle that do not apply to the particular cursor position. For
example, most NPX138N radios can only have a 3, 4, 5, 6 or 7 in the
10’s of MHz position, so the editor does not permit any other numbers
durin
g
editin
g
from the front
p
anel.
FREQUENCY EDITING
WHILE IN CHANNEL EDIT
SELECT
SELECT
1
54
3
2
6
7
8
90
SELECT
SELECT
SELECT
SELECT
ID
CHANNEL EDIT
(BLANK)
#.
When editing a channel ID label, the editor adds
the alphabetic characters and frequently used
symbols to this circle that apply. For example, the
blank (visible as a flashing underline ‘_’ to show
the cursor location), the slash (/) and the number
sign (#).
3.9.2 NEXT Switch
The NEXT switch moves the editing cursor one position to the right if momentarily set to ‘+’ and one
position to the left if momentarily set to ‘−’. The cursor will wrap around when it reaches either end of the
line. The editor will change what choices are valid as the cursor moves from one character to the next.
Sometimes, more than one character will flash. This is because the only valid choices involve multiple
characters, such as the fractional kHz entry for a channel frequency. This is also true for tone code
entries. The SELECT switch will slew through the available entries from an internal table.
3.9.3 EDIT Switch
This locking, center-off switch selects the operating mode of the radio. For normal radio operation set the
EDIT switch to the center or ‘Off’ position. Edited data stores automatically when changed so when
editing is complete, the operator need only set the EDIT switch back to ‘Off’.
3.9.4 HELP Switch
General operation help can be accessed from the initial power-up screen (see section 3.4.1). If basic
help is required when the NPX138N radio is already on, cycle the radio off and then back on again (using
the volume control or the external breaker). The option for comprehensive help will reappear.
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Section 3 Rev: 1.00 Issue 4 Page 3-10
3.10 Status Editing{tc "1.4.8 Status Editing"}
There is simply not enough room on the compact front panel of the NPX138N radio to fit a switch for
every radio function. The solution for this is the use of status lines to display and control features that do
not require immediate accessibility via the front panel.
As when editing channel data, the display shows only allowable options. This mode can also display the
status of the radio quickly, without editing any data. The Status editing process is identical to the channel
editing process only the select switch does not change any information.
To edit status line data, pull and lock the EDIT switch to the right (ST).
Select Setting Display Next Function Status Edit Help
3.10.1 NEXT and SELECT Switch Use
Toggling SELECT will step to the previous/next available setting for the current function.
To advance to the next function, toggle NEXT. Use the SELECT switch to again choose the desired
setting, and continue in this manner until all the radio status lines contain desired information.
When editing is finished, simply return the EDIT switch to ‘Off’ (center position) to store the information.
Exit at any time; it is not necessary to go through the entire status listing.
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3.10.2 Status Edit Features
The STATUS EDIT features currently implemented in NPX138N are as follows:
• TX MODE
There are two modes possible: DUPLEX (repeater) operation, and SIMPLEX (direct) operation.
Duplex means that the radio uses both the RX and TX frequencies programmed into the selected
channel. Simplex means that the radio uses the RX frequency programmed into the selected channel
for both RX and TX purposes. The programmed TX data remains in the radio, but is unused until the
operator returns the radio to duplex mode.
• POWER
The NPX138N radio can transmit at either a HI (10 watt) or LO (1 watt) power setting. Many radio
station licenses have power restrictions at altitude, and must be set to low TX power above 5,000 feet
for legal operation. This feature also helps prevent repeater interference at altitude and permit secure
operations.
• TONES
Radio tones are selectable to ON, OFF, or TX ONLY, thus enabling or disabling any tones set on a per
channel basis through channel editing. TX ONLY enables only the transmit tone, but not the receive
one. See section 3.9 for further details on tones.
• TONE DISP
The radio permits the user to define the tone presentation to suit local operations. This selection can
be for the tone frequency itself (truncated to whole Hz), referred to as FREQ, or it can be one of
several codes. The sequential numbers for the EIA tones are 1-38. The alphanumeric Motorola codes
are referred to as MCODES. The shifted octal codes used by Wulfsberg are referred to as WCODES.
See section 3.9 for further details on tones.
• SCAN
There are three scanning modes available for selection: LIST, PRIORITY, and LIST+PRI. See section
3.10 for further details on scanning.
• P1
This is the Priority channel used in Priority and List+Priority Scanning. It can be set to any valid
channel number, or if not required, can be set to NONE. When the SCAN option is selected to LIST,
the priority channels are not active but are retained in memory. See section 3.10 for further details on
scanning.
• PWR-UP HELP
The display of the HELP screen at power up can be selected on or off.
• PWR-UP CHAN
This is the channel the radio will go to when powered up. The operator can select a specific channel
or set this option to PDC (Power-Down Channel). PDC will cause the radio to power up on the last
used channel.
NPX138N Series Panel Mount FM Transceiver
SM41 Installation and Operation Manual
Section 3 Rev: 1.00 Issue 4 Page 3-12
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3.11 Tones{tc "1.4.9 Tones"}
3.11.1 General
The tone system used by the NPX138N radio is a Continuous Tone-Coded Squelch System (CTCSS), as
defined by an Electronic Industries Association (EIA) standard. The radio adds these tones to the normal
signal modulation (such as voice) to uniquely identify or select a particular radio or group of users.
More commonly, these tones are referred to as sub-audible tones. This is because the filtering action of
the radio eliminates them from the received audio. Therefore neither the sending nor receiving party will
hear them. These tones are also sometimes referred to as Private Line (PL) tones.
3.11.2 Tone Display and Selection
The NPX138N radio displays the tones for the selected channel on the last three positions (far right hand
side) of the RX and TX lines. Use the Channel Edit mode to select and store the appropriate tones for
each channel. The operator can set different tones for receive and transmit. Select ‘−’ if no tone is
required.
By editing the TONE DISP status line, the operator can configure the radio to display the tones using one
of four different methods. The four tone display modes are:
• Tone Frequency (FREQ):
This is the actual frequency of the tone, measured in Hertz (cycles/second). There are only three
digits available on the radio to display this data, so the radio truncates any decimal fraction on the
display (i.e. 103.5 Hz becomes 103). Although not displayed, the radio uses the exact frequency.
• EIA Codes (1-38):
This is a number from 1-38 that identifies the tone in sequential order from lowest (67.0 Hz) to highest
(250.3 Hz)
• Wulfsberg Codes (WCODES):
These are sequential shifted OCTAL codes based on the thumbwheel design of the Wulfsberg C-1000
control. Because they are missing numbers ending in 0 & 9, they can be confusing, especially to
those familiar with the straight sequential number of the EIA codes.
• Motorola Codes (MCODES):
These are alphanumeric codes that often appear in the land mobile business, especially if Motorola
equipment is used.
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SM41 Installation and Operation Manual
Section 3 Rev: 1.00 Issue 4 Page 3-13
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Table 1 below shows the four different display options for each of the available tones.
Tone Frequency (Hz) 1-38 WCODE MCODE
67.0 1 01 XZ
71.9 2 02 XA
74.4 3 03 WA
77.0 4 04 XB
79.7 5 05 SP
82.5 6 06 YZ
85.4 7 07 YA
88.5 8 08 YB
91.5 9 11 ZZ
94.8 10 12 ZA
97.4 11 13 ZB
100.0 12 14 1Z
103.5 13 15 1A
107.2 14 16 1B
110.9 15 17 2Z
114.8 16 18 2A
118.8 17 21 2B
123.0 18 22 3Z
127.3 19 23 3A
131.8 20 24 3B
136.5 21 25 4Z
141.3 22 26 4A
146.2 23 27 4B
151.4 24 28 5Z
156.7 25 31 5A
162.2 26 32 5B
167.9 27 33 6Z
173.8 28 34 6A
179.9 29 35 6B
186.2 30 36 7Z
192.8 31 37 7A
203.5 32 38 M1
210.7 33 41 M2
218.1 34 42 M3
225.7 35 43 M4
233.6 36 44 M5
241.8 37 45 M6
250.3 38 46 M7
Display Options - Table 1
NPX138N Series Panel Mount FM Transceiver
SM41 Installation and Operation Manual
Section 3 Rev: 1.00 Issue 4 Page 3-14
ENG-FORM: 806-0115.DOT
CONFIDENTIAL AND PROPRIETARY TO NORTHERN AIRBORNE TECHNOLOGY LTD.
3.11.3 Turning Tones On and Off
The NPX138N radio also has the capability to have tones enabled or disabled globally. By editing the
TONES status line, the operator can set all the tones ON, OFF or to TX ONLY.
TONES=ON enables all the tones programmed into the individual channels. (Remember that some
channels may have no tones programmed.) Both the frequency and tone of incoming signals must be
correct to hear the receive audio. If the incoming frequency is correct, but the incoming tone does not
match the tone set in the radio, the radio will not produce any audio. The RX indicator lights whether the
logic is correct for audio or not, to warn the operator that the channel is active with radio traffic of some
kind.
TONES=OFF disables all tones. The radio will still display the individual tones on the RX and TX channel
display lines, but only for reference purposes. All incoming transmissions on the RX frequency will be
heard.
TONES=TX ONLY enables all transmit tones but disables all receive tones. This is used on U.S. Forest
Service contracts, for example, where the tones are needed only to open the repeater and serve no RX
squelch function.
3.12 Scanning{tc "1.4.10 Scanning"}
3.12.1 General
Scanning is an automatic internal function that rapidly samples a selected group of channels. It is very
useful for checking radio traffic on one or more channels, while still working a ‘home’ or monitor channel.
When scanning is active, the radio ignores all CTCSS/Sub-audible Tones. It does not test for these
conditions when determining whether or not to lock on to a channel (although tones do remain active for
squelch control). This is because the delay to test for tones is so long (compared to the channel lock-up
time), that it would seriously compromise scanning. It takes almost half a second to provide tone
decoding, which would result in virtually useless scanning of 2 channels per second.
The radio will stop on any flagged channel that has a correct RF signal present, but there may be no
audible signal if the tones do not match those set in the radio. To avoid any confusion, set tones to OFF
(via the status edit mode) during scanning so that all channels will be audible.
In order to be detected properly, a signal needs to be slightly stronger when the radio is scanning than
when the radio is in ‘Normal’ operating mode.
NPX138N Series Panel Mount FM Transceiver
SM41 Installation and Operation Manual
Section 3 Rev: 1.00 Issue 4 Page 3-15
3.12.2 Scan Operation
Activate scanning by moving the SCAN/NORM/GD TX toggle switch to the SCAN position. The ‘home’
channel is the channel that the radio was on before scanning was activated.
The radio scans the home channel and all channels on the ‘scan list’ at a maximum rate of 30 channels
per second.
When the radio is actively scanning, a SCANNING message will appear on the upper row of the display.
When the radio has found and locked onto an active channel, the display will show the correct channel
data corresponding to the display mode selected (ID, RX or TX).
If the operator keys the transceiver while the radio is actively scanning, the radio will be re-channelled to
the ‘home’ channel for transmission. If the radio is locked onto a channel, transmission will occur on that
channel.
From the SCAN status line, the operator may select one of several pre-defined modes that control how
the radio will carry out the scanning function. They are described in the following section.
3.12.3 Scan Modes
Any NPX138N channel can be designated as a PRIORITY channel and/or a LIST channel.
The appropriate scan flags will appear after the channel name on the ID line (p1 and/or sc). Any or all of
the channels can be in the scan list for LIST SCANNING, but only one channel can have the Priority
designation.
Use the status edit mode to select both the priority channel and the SCAN MODE. Use the channel edit
mode to tag channels for list scanning. The three scan modes are as follows:
• LIST Scanning
The second last space on each channel ID line indicates whether that channel is in the scan list or not.
If it displays a dash ‘−’, the channel is not in the list. If the channel is in the list it displays the scan flag
(sc). Use the channel edit mode to change the scan list status for each channel. Any number of
channels may be placed in the scan list; but for effective scanning operation, the number should be
kept to a minimum.
Once scanning is activated (using the front panel SCAN switch), the radio will move through all the
flagged channels in consecutive order until it detects a carrier. It will remain on that channel until traffic
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CONFIDENTIAL AND PROPRIETARY TO NORTHERN AIRBORNE TECHNOLOGY LTD.
NPX138N Series Panel Mount FM Transceiver
SM41 Installation and Operation Manual
Section 3 Rev: 1.00 Issue 4 Page 3-16
stops, and then wait for a 2-3 second latency period to permit the operator to reply. If there is no
further activity, the radio will continue through the list, and then start over. When scanning is turned
off, the radio resumes normal operation on the home channel (the one set before scanning began).
During List scanning, the operator can use the front panel CHAN switch to delete ‘nuisance’ channels.
If the radio locks onto a channel, and the operator does not want to monitor that channel, the CHAN
switch may be moved to the left ‘−’ to temporarily delete that channel from the scan list. That channel
will remain out of the scan list until the operator disables the scan mode (either by moving the scan
switch back to NORM or by turning off the radio).
• PRIORITY Scanning
The radio scans the home channel plus one priority channel. It will continue scanning the priority
channel if it finds an active channel.
To avoid accidental duplication, use the Status Edit mode to set the priority channel. ‘p1’ designates
the priority channel; the lowest priority is the home channel. The ‘p1’ flag will appear on the last space
of the ID line of the appropriate channel.
If the radio receives a transmission on the home channel, it will continue to check ‘p1’. The check
during priority scan is very fast, about every 1/3 second, and will sound like a faint tick when occurring
during other reception. If there is activity on the designated ‘p1’ channel, the radio will re-channel to
that frequency, regardless of activity on other channels.
The radio will return to the home channel 2-3 seconds after activity on the priority channel has ceased.
• LIST+PRIORITY Scanning
In this mode, both LIST and PRIORITY features are combined, so that the radio checks ‘list’ while still
periodically testing for activity on the priority channel. In this case, list channels have a lower priority
than the home channel, and are scanned only when there is no activity on the other two.
3.13 Wideband/Narrowband Operation{tc "1.4.11 Wideband/Narrowband
Operation"}
The NPX138N is capable of operating in either a wideband mode (± 5.0 kHz Rated System Deviation) or
narrowband mode (± 2.5 kHz Rated System Deviation).
3.13.1 Editing Wideband/Narrowband Flag
To edit the Wideband/Narrowband channel characteristic, place the DISP switch to the ID position and
place the radio into channel edit mode. Use the NEXT switch to place the EDIT CURSOR in the correct
display position, marked by the current flag setting (Note: the character should be flashing). To change
this selection use the ‘+’ or ‘−’ SELECT switch. The channel data will save automatically when exiting
‘Edit’ mode.
The ID line displays a ‘ ’ character when the radio is in ‘Wideband’ mode. The ID line displays an ‘ ’
when the radio is in ‘Narrowband’ mode (refer to section 3.8.1).
ENG-FORM: 806-0115.DOT
CONFIDENTIAL AND PROPRIETARY TO NORTHERN AIRBORNE TECHNOLOGY LTD.
NPX138N Series Panel Mount FM Transceiver
SM41 Installation and Operation Manual
Section 3 Rev: 1.00 Issue 4 Page 3-17
ENG-FORM: 806-0115.DOT
CONFIDENTIAL AND PROPRIETARY TO NORTHERN AIRBORNE TECHNOLOGY LTD.
3.14 Configuration Mode{tc "1.4.12 Configuration Mode"}
This mode of operation is not required for normal operation and is intended to aid in servicing and radio
set-up.
Various firmware functions of the radio can be set via this mode.
Entering this mode requires a special code and switch sequence, and should be USED ONLY AT THE
FACTORY OR BY QUALIFIED SERVICE PERSONNEL.
3.14.1 Using Configuration Mode
CAUTION:
Incorrect use of this mode may render the radio inoperable.
Use this function with extreme care.
If you have any questions, please call Northern Airborne Technology Ltd
prior to use.
To enter this mode, do the following, EXACTLY AS DESCRIBED:
a) With the power turned off, lock the EDIT switch into the CH position.
b) Turn on the radio. The ‘Lock EDIT switch OFF for Norm OP’ message should appear.
c) Press the HELP button. The ‘...PASSWORD:’ message should appear.
d) Although there is no cursor on the screen, use the SELECT and NEXT controls to enter the
configuration mode password, which is IAC. Be sure to use the NEXT switch after entering the
last character. The ‘Config Mode...’ screen should appear.
e) Depending on the style of radio and the options selected, the information on this and subsequent
screens will vary.
Note: Some of the features listed in the following table may not be displayed.
f) Using the normal editing procedure (SELECT/NEXT), select a valid option for each feature
presented.
g) It is up to the operator to ensure that the selected options are compatible with each other, and
with the hardware being used. If they are not, the radio may not operate correctly.
Read the following table carefully and ensure that all configuration options are completely understood.
NPX138N Series Panel Mount FM Transceiver
SM41 Installation and Operation Manual
Section 3 Rev: 1.00 Issue 4 Page 3-18
ENG-FORM: 806-0115.DOT
CONFIDENTIAL AND PROPRIETARY TO NORTHERN AIRBORNE TECHNOLOGY LTD.
3.14.2 Configuration Option Table
FEATURE VALID OPTIONS COMMENTS
STATUS DISPLAY
ON POWER-UP ON, OFF Determines whether or not the radio status lines
are displayed on power-up.
EXT. DATA PAD ON, OFF Determines whether or not the radio will accept
data from an external data entry pad.
LOWEST FREQ. 138, 150 Sets the lower limit (in MHz) for frequency
editing. All NPX138N radios can be selected to
either option.
CHANS. INST. 20, 40, 60, 80, 100
The number of channels available in the radio.
Does NOT include guard channels.
TX TIME OUT 000, 030, 060, 090, ... 240 The time, in seconds, the Transmitter is allowed
to be active for one continuous period. Intended
to prevent ‘stuck mic’ conditions from damaging
the equipment.
GD RX EDIT
(-x7x models only)
ON, OFF Determines whether or not the guard channels
are editable from the front panel.
Configuration Options - Table 2
Section 3 ends