I mounted the TT22 remote box under the cockpit floor in front of the
stick in my LAK-17a.Â* It was a large empty space intended for a "nose
hook" which my glider did not have.Â* I purchased the custom cable but,
due to restrictions in the cable path, had to remove the connector from
one end and reinstall it after the cable was run.

I took the transponder with me when I acquired the Stemme and it was
simple to mount it vertically in the instrument box behind the panel.Â*
Later, when I added ADS-B, I mounted the TN72 box right next to the
TT22.Â* The TN72 is powered by a 1-Amp circuit breaker as required by the
STC for Certificated aircraft.Â* I also included a pitot-activated
"squat" switch for air/ground determination.Â* The TA70 antenna is
mounted on a shelf fabricated of aluminum sheet and attached to one of
the steel tubes in the engine bay.Â* It is located above the engine and
under the fiberglass turtle deck, which is easily removable.

As an aside on custom cables.Â* If you're flying an Experimental glider,
the custom cable should work just fine.Â* But, if you fly a Certificated
glider, it's not so simple.Â* In my case, the custom cable took
electrical power from the TT22 to power the TN70 which does not conform
to the STC.Â* I had to open the cable shells on the custom cable to
disconnect the power wires and I also had to add two wires for the
pneumatic air/ground switch.Â* The work was not difficult for anyone
familiar with cable assembly, but you should know.

I have a power flarm portable which is mounted to the top of the glare
shield which is not pertinent to your question.Â* The PF portable does
receive ADS-B traffic transmitted in response to my ADS-B Out
transmissions.Â* Targets are displayed on my ClearNav II moving map and
on a separate Flarm View display.

On 11/17/2019 8:09 PM, son_of_flubber wrote:
Another issue to plan is where and how to physically mount the Trig transponder and GPS bricks. Using a long cable to connect the transponder brick to the panel unit gives you more flexibility on where to place the bricks. I mounted my two bricks on a vertical piece of plywood behind my headrest. I fabricated a perforated metal cover to insure air circulation around the bricks even if my 'survival bag' on the turtle deck is pressing against the perforated cover.

There's no carbon fiber in my glider. The GPS antenna is velcro-ed inside the fuselage above the turtle deck. The transponder antenna is inside the fuselage about four feet behind the bricks in the boom (as far away as possible from my head and metal parts). I made a special tool to reach back into the fuselage. Mounting the transponder antenna was by far the hardest part of the installation task. Powerflarm antennas are in the nose in front of the panel, so I have about five feet between my two GPS antennas.

I recommend giving yourself a lot of time to sort out where and how to mount the physical pieces. The wiring is trivially easy if you buy a custom made wiring harness.

--
Dan, 5J