How sensitive is Garmin 20A?

[jantar]

I currently have FreeFlight 1201 as a GPS source connected to Trig T22. I also have a couple of "experimental" GPS sources driving other instruments.

I find the non-TSO GPS sources working perfectly in a wooden hangar while the FreeFlight 1201 is not able to obtain a lock, or at least there is no position displayed on T22. The other instruments work just fine. Of course the FreeFlight 1201 works just fine outside, but I had a difficult time finding a place for an antenna that would not cause reception problems.

FreeFlight 1201 being an old design probably has low sensitivity GPS receiver. Does anyone have experience with Garmin 20A and is able to obtain position in a garage or a wooden hangar? I presume that Trig will only display position if the quality of signal is acceptable and that might be the reason for the difference in performance.

Thank you in advance,
Andrzej

[maus92]

I have a GPS 20A with the antenna installed on the top of the fuselage behind the canopy. It does not receive GPS signals while inside my metal hanger with the door open, but neither did the G3X internal GPS with its antenna on the glare shield.

My iPhone does receive GPS in the hanger.

Once outside, all the receivers work fine. If you wanted / needed, you *could* install a GPS repeater inside your hanger for testing. As I understand it, aviation antennas are not necessarily optimized for maximum reception, their designs are skewed to reject / minimize interference, and receive from low angles close to the horizon.