Copyright © 2016  Grand Rapids Technologies, Inc.

Electronic Flight Instrumentation for Experimental Aircraft Since 1991

The following is a list of popular transponders used by GRT customers.  The Trig TT22 is recommended for its price, remote interface and ADS-B Out (Extended Squitter) capability.  This list is not all-inclusive; our built-in encoder will feed most Mode C and Mode S transponders including Becker, Microair and King, with support for both Grey code and serial encoder data.

There are many choices available for transponders these days. Mode C? Mode S? Extended squitter? Remote-mount?

Transponder Options

Make

Model

Type

Mount

Retail Price

Website

Available through GRT

Garmin

GTX327

Mode C

Panel

$1,789


No

GTX 330/ 330-ES

Mode S

Panel

$3,649


No


Trig

TT21

Mode S

1090ES†

Remote

 $1,875*

Only with purchase of HXr System

TT21

Mode S

1090ES†

Panel

$2,239

No

TT22

Mode S

1090ES

Remote

 $2,200*

Only with purchase of HXr System

TT22

Mode S

1090ES

Panel

$2,499

No

TT31

Mode S

1090ES

Panel

$2,675

No

Sandia

STX 165R

 Mode C

Remote

$1,550


Yes

INFO INFO

NOTE: Retail prices are from a reputable dealer for comparison purposes only – may not be current.

Remote Mount interfaces apply to HXr only.  

*GRT price includes single-display remote serial adapter for HXr.  Dual-display adapter is available for $175.  Dual-display adapter allows two display units to control transponder, providing redundancy if one display unit is lost.

†TT21 does not comply with U.S. 2020 ADS-B mandate, which requires Class 1 transponder (higher output wattage).

INFO INFO INFO

Document

Revision

Date


Trig TT21/TT22 Supplement for HXr

A2

28-May-2014


Trig TT21/TT22 Mounting Tray and Overall Dimensions

A

06-Nov-2012


Trig TT21/TT22 Serial Adapter Dimensions*

1

06-Nov-2012


Trig TT21/TT22 Wiring Diagram for HXr

1

06-Nov-2012


Trig TT22 Unit Photos*

1

06-Nov-2012


Garmin GTX327 GRT Supplement

A

15-Dec-2012


Garmin GTX330 GRT Supplement

A1

23-Oct-2013


*Note: Trig serial adapters have the same dimensions as the drawings and   photos shown, but now have a metal case.

Transponder Documentation

Here you’ll find all user documentation created by GRT for popular transponder options, including mounting templates and supplements for wiring, setup and use.

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