Wulfsberg Electronics Division 3YH NPX138 User Manual
Published on
August 1, 2012
Installation and Operation Manual
NPX138N Series
Panel Mount FM Transceiver
SM41
ISSUE 4.01
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
NPX138N Series Panel Mount FM Transceiver
SM41 Installation and Operation Manual
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 applica ble 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
Installation and Operation Manual Page ii
ENG-FORM: 820-0116.DOT
CONFIDENTIAL AND PROPRIETARY TO NORTHERN AIR BORNE TECHNOLOGY LTD.
NPX138N Series Panel Mount FM Transceiver
SM41 Installation and Operation Manual
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
4.00 N/A - Nov 10, 2003
Rewritten in latest format Aug 17, 2010
Installation and Operation Manual Page iii
ENG-FORM: 820-0116.DOT
CONFIDENTIAL AND PROPRIETARY TO NORTHERN AIR BORNE TECHNOLOGY LTD.
NPX138N Series Panel Mount FM Transceiver
SM41 Installation and Operation Manual
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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CONFIDENTIAL AND PROPRIETARY TO NORTHERN AIR BORNE TECHNOLOGY LTD.
NPX138N Series Panel Mount FM Transceiver
SM41 Installation and Operation Manual
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
Installation and Operation Manual Page v
ENG-FORM: 820-0116.DOT
CONFIDENTIAL AND PROPRIETARY TO NORTHERN AIR BORNE TECHNOLOGY LTD.
NPX138N Series Panel Mount FM Transceiver
SM41 Installation and Operation Manual
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 North ern
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 CT CSS 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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CONFIDENTIAL AND PROPRIETARY TO NORTHERN AIR BORNE TECHNOLOGY LTD.
NPX138N Series Panel Mount FM Transceiver
SM41 Installation and Operation Manual
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
Frequency range 138.000 MHz to 173.995 MHz
Tone capability 38 standard CTCSS tones
Operating mode simplex or semi-duplex
balanced/unbalanced
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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CONFIDENTIAL AND PROPRIETARY TO NORTHERN AIR BORNE TECHNOLOGY LTD.
NPX138N Series Panel Mount FM Transceiver
SM41 Installation and Operation Manual
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 mal e (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
Lighting Power
Special Options
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Encryption
NPX138N Series Panel Mount FM Transceiver
SM41 Installation and Operation Manual
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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CONFIDENTIAL AND PROPRIETARY TO NORTHERN AIR BORNE TECHNOLOGY LTD.
NPX138N Series Panel Mount FM Transceiver
SM41 Installation and Operation Manual
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 AIR BORNE TECHNOLOGY LTD.
NPX138N Series Panel Mount FM Transceiver
2.4.1 Warnings
Set the headset volume control to the minimum setting prior to
conducting tests, and slowly increase the volume to a comfortable
2.4.2 Cautions
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
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
SM41 Installation and Operation Manual
WARNING:
High volume settings can cause hearing damage.
listening level.
CAUTION:
guidelines are not followed.
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 solde r sleeve s (fo r 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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NPX138N Series Panel Mount FM Transceiver
SM41 Installation and Operation Manual
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 bundle s 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- 1 B C hange 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- 1 B C hange 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 in ches) 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.
Section 2 Rev: 1.00 Issue 4 Page 2-3
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NPX138N Series Panel Mount FM Transceiver
SM41 Installation and Operation Manual
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
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.
Light Voltage
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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NPX138N Series Panel Mount FM Transceiver
SM41 Installation and Operation Manual
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
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