Trig

Trig Avionics Limited

Company Overview
Trig Avionics Limited was founded in January 2004 to develop innovative avionics products for general aviation. Based in Edinburgh, Scotland, Trig are specialists in low power, high tech solutions to existing and emerging requirements in general aviation avionics. Trig is a privately held limited company.

Trig Flow Chart - Which GPS for ADS-B OUT for Experimental and non-Experimental
TrigWhichGPSforGlider.pdf

New TY91 Panel Mounted Aviation Radio
The new TY91 radio is a very interesting product. It looks great in the panel next to a Trig TT21 or TT22 transponder. The dual-monitor function makes it possible to hear transmissions on the standby frequency if nothing is being received on the main frequency - enhancing safety.

TT21 & TT22
The TT21 and TT22 are a very interesting transponders. They are Mode S transponders with built-in altitude encoders, and remote heads - at a great price! Also, the TT21 uses half the power used by the Becker ATC4401 - which is very impressive. You can see a current draw comparison that includes the current required by the altitude encoder used by a Becker transponder. The TT21 is a Class 2 transponder with 125 Watts of transmit power which is rated for use up to 15,000 feet. The TT22 is a Class 1 transponder with 250 Watts of transmit power. Class 1 transponders are used on high performance aircraft – those cruising faster than 175 knots, and operating above 15,000 feet.

ADS-B Out
The Trig TT-21 does not meet the FAA 2020 ADS-B Out requirement for powered aircraft (that gliders are exempt from), and therefore also may not be suitable to provide ADS-B out in gliders should gliders lose that exemption in future. The higher power Trig TT22 does meet the FAA 2020 ADS-B Out requirements. Both the Trig TT21 and TT22 are usable as basic transponders (without 1090ES Out) in the USA, now and after 2020.

A Transponder in Every Sailplane
I strongly believe that every sailplane should have a working transponder in it. I'm sure you will think that is because I sell them. But the main reason is that I fear that in the future a collision will occur between a glider (without a transponder) and a commercial airliner. In addition to the tragic loss of life, we soaring pilots may lose access to airspace. It is my sincere hope that this transponder will break down many of the barriers which have kept glider pilots from installing transponders in their gliders. The units small size and low power consumption make it very attractive.

Brochures and Manuals
TT21 and TT22 Mode S Transponder Operating Manual
TT21/TT22 Mode S Transponder Installation Manual

Transponder Overview Article
Eric Greenwell has written a very nice article which gives an overview of transponder terminology and available products. This article was originally published as two articles in Soaring magazine in February and March 2002,
and updated January, 2008 for publication on the Soaring Safety Foundation web site. Eric flies with a Becker transponder in his motorglider.
The article is available here: https://www.soaringsafety.org/accidentprev/index.html

Transponder Antenna Tips
DG has an excellent document on their web site with details on how to mount transponder antennas to gliders.
http://www.dg-flugzeugbau.de/Data/TN-DG/service-infos/2004-53-e.pdf

Warranty (U.S.A. Customers)
SEA_TT21_Warranty.pdf