MGL Avionics User Forum

Hello! I have an Explorer EFIS -Trigg TT22 transponder-SP12 ADSB Out system. During certification testing it was noted that the length/width parameters are being transmitted as too large (>90) and the GPS antenna offset was not being transmitted at all. The transponder was updated by Mid-Continent and certified as working ok. The EFIS menu does not provide for GPS Antenna offset input anywhere. Wiring checks out ok. Both MGL and Trigg support cannot seem to pinpoint the problem. Can anybody suggest something? Been trying to solve this problem for almost 7 months now. Thanks! Frank A Pisz

The GPS antenna offset is being transmitted as 0/0. There is no current function to set the antenna offset although it may be included in the future if there is demand to cater for larger aircraft.
Length and Width however can be set.

Thank you for your quick response. The length and width were set to the proper dimensions through the EFIS, but the transponder transmits values for length and width which are much too large and not consistent with the settings. How might I correct this problem? Thank you! Frank A Pisz

Is it possible this is an internal EFIS or SP 12 problem?

Also, I forgot to mention, the transponder was sent to Mid-Continent for upgrade and was returned as upgraded and in proper working order. Thanks!

Frank Pisz

OK, just finished doing some tests.

The antenna offset as well as the Width/Length code is sent ONLY during ground operation of the transponder. Currently the Trig transponder does not transmit ES at all in the ground state. BDS 0,6 that contains these values is never transmitted.

Another issue re the EFIS/TT2x compatibility- I have a customer reporting below re not being able to load the ICAO code via an iEFIS Lite.
The EFIS expects octal code input, the Trig expects hexadecimal, and somewhere in the middle things are not getting translated and/or transferred.

The issue is not the hex to octal conversion, I completed this while inspecting the aircraft. Even with the Hex converted to Octal code the transmitted data was incorrect.
The test equipment could not decode the message and reported a default code of 123456. Country identifier was also Russian federation.
Although ultimately the Hex or Octal code references an ICAO 24 bit address, I believe the Trig cannot receive this address as Octal and requires the format to be HEX. Below is an excerpt from the Trig Installation manual.

6.1.2Aircraft Address Programming The Mode S Address is a 24 bit number issued to the aircraft by the registration authority for the aircraft. These addresses are usually written as a 6 digit hexadecimal number, although you may also encounter one written as an 8 digit octal number. The TT21/TT22 only understands the hexadecimal format, so you must first convert an octal number to hexadecimal.

I will check what I entered on mine next time I'm at the aircraft but my iEFIS Explorer Lite works well with my TT21 and has done from day one.

I will check what I entered on mine next time I'm at the aircraft but my iEFIS Explorer Lite works well with my TT21 and has done from day one.

Thanks.
The customer has not yet given me the desired code and the octal he entered, so there is still the possibility he got it wrong.
Though I would have expected some change from the default 123456 no matter what he entered.

Sorry for the delay but I did, at last, manage to get to the hangar today and have a look at the transponder set up.

I have the MGL interface between my iEFIS Lite and Trig TT21 transponder. I only have the TT21 body i.e no panel controller and all control is through the EFIS. This really was a plug 'n' play and worked from day one.

https://www.parts4aircraft.com/mgl-avio ... -interface

I checked today and it is very definitely an Octal input in the iEFIS Lite (as you said). I converted my Octal code to HEX today (to check) and it is correct. However, I did not have to do anything else with the TT21 set up. In fact, there's no way that I can even get into the 'normal' TT21 set up, as you would with a panel controller. In other words, I entered the Octal code and it worked without trying to fiddle around with the TT21.

The 'Type' is Mode S on CAN.