trig TN72 User manual

TN72 TABS GPS Receiver
Installation Manual
01691-00-AG
5 January 2018
Trig Avionics Limited
Heriot Watt Research Park
Riccarton, Edinburgh
EH14 4AP
Scotland, UK
Copyright Trig Avionics Limited, 2016

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CONTENTS
1. PREFACE...............................................................................................1
1.1 PURPOSE...........................................................................................1
1.2 SCOPE...............................................................................................1
1.3 CHANGES FROM PREVIOUS ISSUE......................................................1
1.4 DOCUMENT CROSS-REFERENCES......................................................1
2. INTRODUCTION..................................................................................2
2.1 TN72 DESCRIPTION ..........................................................................2
2.2 INTERFACES......................................................................................2
3. TECHNICAL SPECIFICATIONS.......................................................3
3.1 TN72 GPS RECEIVER UNIT (01655-00)............................................3
3.2 INSTALLATION APPROVAL.................................................................3
3.3 INCOMPLETE TSO ARTICLE...............................................................4
4. UNIT AND ACCESSORIES SUPPLIED.............................................5
4.1 TN72 GPS RECEIVER ITEMS.............................................................5
4.2 INSTALLATION KIT............................................................................5
4.3 REQUIRED ITEMS ..............................................................................5
5. INSTALLATION...................................................................................7
5.1 UNPACKING AND INSPECTING EQUIPMENT........................................7
5.2 GPS RECEIVER MOUNTING...............................................................7
5.3 COOLING REQUIREMENTS .................................................................7
5.4 TN72 GPS RECEIVER ELECTRICAL CONNECTIONS ...........................8

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5.4.1 TN72 Interface –Pinout...........................................................8
5.5 TN72 GPS RECEIVER INTERFACE DETAILS.......................................8
5.5.1 Power Input..............................................................................8
5.5.2 GPS Position Output................................................................8
5.5.3 One PPS Output.......................................................................9
5.6 DCONNECTOR CRIMP TERMINALS ...................................................9
5.7 WIRING CONSIDERATIONS...............................................................10
5.8 ANTENNA INSTALLATION................................................................10
5.8.1 Antenna Power.......................................................................10
5.8.2 Recommended Cable..............................................................10
5.8.3 QMA Connector.....................................................................11
6. INSTALLATION SETUP AND TEST...............................................13
6.1 CONFIGURATION ITEMS...................................................................13
6.1.1 GPS Input...............................................................................13
6.1.2 GPS/TIS Line Speed...............................................................13
6.1.3 GPS Certification Level .........................................................14
6.1.4 GPS NAC velocity ..................................................................14
6.1.5 GPS Antenna Offset ...............................................................14
6.1.6 1090 MHz Receiver Installed.................................................14
6.1.7 UAT Receiver Installed ..........................................................15
7. POST INSTALLATION CHECKS....................................................16
8. CONTINUED AIRWORTHINESS....................................................17
9. LIMITED WARRANTY.....................................................................18
10. ENVIRONMENTAL COMPLIANCE...........................................19

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11. ADS-B COMPLIANCE...................................................................21
11.1 TSO-C199 TABS COMPLIANCE .....................................................21
11.2 FAA 91.227 COMPLIANCE..............................................................22
11.3 CS-ACNS COMPLIANCE .................................................................22
11.4 ADS-B SUPPORT ............................................................................22
12. INSTALLATION DRAWINGS......................................................23
13. BASIC INTERCONNECT DIAGRAM .........................................24

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1. Preface
1.1 Purpose
This manual describes the physical and electrical characteristics and the
installation requirements for a TN72 TABS GPS Receiver and recommends the
configuration settings for the associated transponder.
1.2 Scope
This document applies to the installation of the TN72 TABS GPS Receiver.
Information about configuration of Trig transponders is included, but for full
installation data on the transponder please use the applicable transponder
installation manual.
1.3 Changes from Previous Issue
Section 3.1
Added ETSO C199 Certification
Section 4.3
Corrected error in antenna specification
Section 6.1.1
Added SDA information
Section 13
Updated diagram to include TT31
1.4 Document Cross-References
00455-00
TT31 Transponder Installation Manual
AR
00560-00
TT21/TT22 Transponder Installation Manual
AQ

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2. Introduction
2.1 TN72 Description
The TN72 TABS GPS Receiver is a TSO-C199 class B compliant GPS,
suitable for use as an ADS-B position source for a Trig transponder. When
installed in accordance with this manual it forms part of an ADS-B Out system
that is compatible with airborne traffic systems and surface surveillance
equipment.
The Traffic Awareness Beacon System (TABS) is intended for voluntary
equipage on aircraft exempted from carrying Automatic Dependent
Surveillance - Broadcast (ADS-B) equipment, such as gliders, balloons and
aircraft without electrical systems. The TN72 in conjunction with a Trig
transponder provides a fully compliant solution for those aircraft.
The TN72 can also be fitted to any aircraft operating outside ADS-B mandated
airspace to enhance traffic situational awareness. The TN72 provides a
position source with TSO Design Assurance and non-zero quality indicators for
interoperability with all kinds of traffic receivers.
Under certain circumstances the TN72 can also be used to satisfy the position
source requirements of FAR 91.227 in the USA.
2.2 Interfaces
The TN72 has a single QMA antenna interface suitable for connection to a
range of active GPS antennas. A 9 way D type connector is used for power
input and data output from the GPS.
Power Input
The TN72 operates on 11 to 33 volts DC, and is
compatible with 12, 14, 24 and 28 volt systems.
GPS Interface
An RS232 compatible output provides the GPS data to the
transponder.
Pulse Output
An RS422 compatible output provides one pulse per
second synchronised to the GPS clock. This output is not
used on the Trig transponders.

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3. Technical Specifications
3.1 TN72 GPS Receiver Unit (01655-00)
Specification
Characteristics
Compliance
TSO-C199 Class B
ETSO-C199 Class B
Applicable documents
TSO-C199, RTCA DO-160G, RTCA DO-260B
Power Requirements
11 –33 Volts DC. Typical 1 Watt @ 14Volts.
Altitude
35,000 feet
Operating Temperature
-40°C to +70°C
Receiver Type
1575.42 MHz L1, C/A code receiver with
SBAS capability
Tracking Sensitivity
-135 dBm
Physical Specifications (including mounting flange)
Height
30mm (1.2”)
Width
80mm (3.1”)
Length
75mm (2.9”)
Weight
0.22lbs. (110 g)
3.2 Installation Approval
The conditions and tests required for the TSO approval of the TN72 TABS
GPS Receiver are minimum performance standards. It is the responsibility of
those desiring to install this receiver on or within a specific type or class of
aircraft to determine that the aircraft operating conditions are within the TSO
standards. The receiver may be installed only if further evaluation by the
user/installer documents an acceptable installation that is approved by the
appropriate airworthiness authority.

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3.3 Incomplete TSO article
The TN72 is a remote mount TSO-C199 compliant class B position source. As
such the following functional requirements from TSO-C199 Appendix 1 are not
implemented.
•A1.2.7.1 Antenna Requirements
•A1.2.7.2 Antenna Installation
•A1.2.7.3 Antenna Hazards
•A1.2.8.2 Battery Operation

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4. Unit and Accessories supplied
4.1 TN72 GPS Receiver Items
The TN72 GPS Receiver includes the following items:
Unit Description
Qty
Part Number
TN72 GPS Receiver
1
01655-00-01
TN72 GPS Installation Kit
1
01690-00
4.2 Installation Kit
The TN72 installation kit includes the following items:
Unit Description
Qty
Part Number
TN72 Installation Manual
1
01691-00
Connector Co-axial QMA
1
01697-00
Headshell, 9 Way
1
00725-00
9 way D-type contact housing (female)
1
00727-00
Crimp Terminal, Female, 22-24 AWG
9
00730-00
4.3 Required Items
Additional items you will require, but which are not in the TN72 package,
include:
•Antenna and fixing hardware. The TN72 is compatible with any GPS
antenna approved to ETSO C190 or C144a; the recommended antenna
is the Trig TA70. Where a non-TSO antenna is used, the antenna
must include an integral amplifier with gain of not less than 20dB.
•Cables. You need to supply and fabricate all required cables.
Guidance on cable types is given in section 5 below.

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•Fixings. To secure the GPS receiver to the airframe you will need 4
flat head screws and four self-locking nuts. If the aircraft does not
have existing mounting provisions you may need to fabricate
additional brackets to support the GPS receiver.
To complete the ADS-B Out solution you will need an appropriate transponder.

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5. Installation
5.1 Unpacking and Inspecting Equipment
Carefully unpack the GPS receiver and make a visual inspection of the unit for
evidence of any damage incurred during shipment. If the unit is damaged,
notify the shipping company to file a claim for the damage. To justify your
claim, save the original shipping container and all packaging materials.
5.2 GPS Receiver Mounting
The TN72 TABS GPS Receiver is designed to be mounted in any convenient
location in the cockpit, the cabin, or an avionics bay.
The following installation procedure should be followed, remembering to allow
adequate space for installation of cables and connectors.
•Select a position in the aircraft that is not too close to any high
external heat source. (The TN72 is not a significant heat source itself
and does not need to be kept away from other devices for this reason).
•Avoid sharp bends and placing the cables too near to the aircraft
control cables.
•Secure the unit to the aircraft using four screws and locking nuts.
Rivets can alternatively be used. The GPS receiver should be
mounted to a flat surface.
5.3 Cooling Requirements
The TN72 TABS GPS Receiver meets all applicable TSO requirements without
forced air-cooling.
Attention should however be given to the incorporation of cooling provisions to
limit the maximum operating temperature if the TN72 is installed in close
proximity to other avionics. The reliability of equipment operating in close
proximity in an avionics bay can be degraded if adequate cooling is not
provided.

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5.4 TN72 GPS Receiver Electrical Connections
The TN72 has a single 9 way male socket which provides the data and power
connections to the GPS receiver. A single QMA coaxial connector attaches to
the antenna cable.
5.4.1 TN72 Interface –Pinout
Pin
Signal
Direction
1
Power 11-33V
Power
2
Ground
-
3
One PPS RS-422 A
Output
4
One PPS RS-422 B
Output
5
Ground
-
6
RS232 Control
Input
7
Position Out
Output
8
Reserved
-
9
Reserved
-
5.5 TN72 GPS receiver Interface Details
5.5.1 Power Input
The power supply can be 11-33 Volts DC; no voltage adjustment is required.
Use a 1 Amp circuit breaker for power supply protection to the TN72.
5.5.2 GPS Position Output
The GPS position output is an RS-232 compatible port operating at 9600 bps.
It should be routed to the appropriate GPS position input on the transponder.
The data format is NMEA compatible with proprietary extensions. It can be
used as a position input for any NMEA compatible equipment.

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In normal operation the RS232 control input to the GPS is not used.
5.5.3 One PPS Output
The TN72 provides a one pulse-per-second output that is synchronised to the
GPS clock. This is encoded on an RS-422 balanced pair.
The one PPS output is not used in Trig transponders.
5.6 D Connector Crimp Terminals
The 9 way connector supplied with the TN72 installation kit is a MIL standard
version of the popular sub miniature D type connector family, and use
individual crimp terminals and a receptacle. The MIL specification for this
family of connectors is MIL-C-24308. We supply crimp terminals because
these are more reliable than soldered connections, and are easier to assemble
in-situ in an aircraft, where soldering is impractical. They also allow individual
wires to be removed and replaced in a receptacle without replacing the whole
connector.
The socket contacts conform to MIL part number M39029/63-368, and are also
suitable for wire gauges from 20 to 24 AWG.
These contacts are widely used in avionics installation, and there are many
tools available on the market that will reliably crimp them to the wiring.
Because the contacts are a MIL standard, there is also a MIL standard for the
crimp tool, although other proprietary solutions are also available.
The MIL reference for the basic style of hand tool is M22520/2-01. This style
of tool can crimp many different contact types, and relies on interchangeable
"positioners" to hold the actual contact in use. The MIL reference for the
positioner that you need for the crimps we supply is M22520/2-08.
Any tool that complies with these references can be used to crimp these
contacts. One of the most popular vendors of these small hand tools is Daniels
Manufacturing Corporation (see www.dmctools.com). Their AFM8 hand tool
complies with M22520/2-01, and their K13-1 positioner is M22520/2-08
compliant, so the combination will crimp the supplied connectors.
Once crimped, the contacts should be slotted into the rear of the connector
shell. Push the contact in until the retaining tab clicks into place. Tug gently to

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confirm the contact is locked in place.
5.7 Wiring Considerations
A typical installation uses two wires for power and ground, and two wires to
connect from the GPS to the transponder, signal and ground.
In a certified installation the normal wire choice would be Tefzel hook-up wire.
Wire of 20 AWG is more than adequate for the task; in installations where
weight is an issue, wire of 22 or 24 AWG can also be used. Where lighter
wires than 20 AWG are used the individual wires should be laced together for
support.
5.8 Antenna Installation
The antenna should be installed according to the manufacturer’s instructions.
The GPS/SBAS antenna mounting location and cable connections are very
important. The antenna should not be mounted close to VHF COM transmitter
antennas, and other antennas emitting high power. Special care should be taken
to ensure that the GPS antenna is not mounted in close proximity to antennas
that may emit harmonic interference at the L1 frequency of 1575.42 MHz.
Refer to AC 20-138C “Airworthiness Approval of Global Navigation Satellite
System (GNSS) Equipment” for additional information and guidelines. For
best performance, select a location with an unobstructed view of the sky above
the aircraft when in level flight.
5.8.1 Antenna Power
The TN72 receiver utilises an active antenna which means the antenna includes
a low noise amplifier. The power for the low noise amplifier is provided from
the GPS receiver via the antenna coax cable. The TN72 supplies a nominal 5
volt supply at up to 40 mA.
5.8.2 Recommended Cable
RG400 or RG142 is recommended. A maximum length of 50 ft is
recommended. The cable loss including connectors should not exceed 10dB.

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5.8.3 QMA Connector
This section describes the technique for attaching the antenna cable to the
supplied QMA connector.
The supplied connector can be completed using a wide range of commercial
crimp tools. The die apertures for the outer shield should be approximately 5.5
mm.
•Strip back the coax cable to the dimensions in the table, as shown in
the diagram below. Slide 25 mm (1 inch) of heat shrink tubing over
the cable.
•Slide the outer crimp sleeve over the cable –it must go on before
securing the centre contact.
Dimension
Cut size
(mm)
Cut size
(inches)
A
12
0.47
B
3.7
0.14
C
2
0.08
•Solder the centre contact to the cable –heat contact using a dry
soldering iron, flow a small amount of solder into the bore hole of the
contact, insert cable and solder to contact. Clean contact and cable,
remove excess solder.
•Insert the cable into the connector –the centre contact should click
into place in the body, the inner shield should be inside the body of the
connector and the outer shield should be outside the body.

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•Crimp the outer sleeve over the shield.
•Slide heat shrink tubing forward (flush to connector) and heat to
shrink the tubing.

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6. Installation Setup and Test
There are no configuration items on the TN72. This section describes the
correct configuration for a connected Trig TT21 or TT22 transponder and
assumes that the transponder is using software version 2.12 or later. The
process for configuring the TT31 transponder is similar. Earlier transponder
software versions can use the TN72 as an uncertified NMEA position source,
but may not recognise the later settings described here.
6.1 Configuration Items
6.1.1 GPS Input
The TN72 outputs NMEA encoded position and velocity data as well as
additional integrity information used for TSO-C199 compliance. The
transponder can therefore be configured to operate using the TN72 as an
uncertified NMEA position source, as a TSO-C199 TABS position source, or
in certain circumstances as a FAR 91.227 compatible position source. Select
one of the following:
NMEA 0183
Transponder sends ADS-B data, SIL set to zero.
C199 TABS
Transponder sends ADS-B data in accordance
with TSO C199; SIL = 1, SDA = 1.
Trig TN72 SIL 3
Transponder sends ADS-B data in accordance
with FAR 91.227; SIL = 3, SDA = 2.
6.1.2 GPS/TIS Line Speed
The TN72 runs at 9600 bps.
Note: The TIS output and GPS input speeds are not separately
controlled on the TT21/TT22. Not all combinations of GPS input and
TIS output will work if the TIS device operates on a fixed speed other
than 9600 bps.

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6.1.3 GPS Certification Level
If you are using the TN72 as a simple NMEA GPS source, it should be set to
uncertified. When a C199 TABS GPS source is selected the certification level
is not used by the Trig transponder; TSO-C199 uses a special encoding of the
design assurance flags. When compliance with FAR 91.227 is being
configured, the GPS certification level can be set to level C.
6.1.4 GPS NAC velocity
The GPS NACv for the TN72 is 10 m/s. This configuration item is not
required on a Trig transponder if the C199 TABS GPS source is selected –the
TABS system automatically allocates the NACv value.
6.1.5 GPS Antenna Offset
The GPS antenna offset is used together with the aircraft length and width to
manage taxiway conflicts. A TN72 GPS installation does not report the
geographic position of the centre of the aircraft; instead it reports the location
of the GPS antenna (not the GPS receiver). In normal flight operations this
distinction is of no practical importance at all, but if ADS-B is used to manage
taxiway conflicts, a significant offset in antenna position could mean that the
aircraft is not in the same place as the ADS-B reported position. Although
primarily intended for position correction on large transport aircraft, General
Aviation aircraft can also have a significant offset. For example, if the aircraft
has a long tail boom and the GPS antenna is on the top of the tail, the GPS
position could be 4 metres or more from the nose of the aircraft.
Enter the position of the GPS antenna relative to the nose of the aircraft. The
position is stored and transmitted to the nearest 2 metres; great accuracy in
measurement is not required.
6.1.6 1090 MHz Receiver Installed
The ADS-B transmissions include an indication to the ground stations of
whether your aircraft includes a 1090 MHz ADS-B receiver. This can be used
by the ground stations to manage the volume of traffic they must send. Set this
to “Yes” if the aircraft has a 1090 MHz ADS-B receiver installed.