More avionics tinkering

Mostly sort of tinkering around tonight. I did decide that I wanted to try and verify a few more things before moving on to the canopy; basically this is me wanting to nail down components in the tail as much as possible before turning that part of the plane into a cave. The verification I wanted to do involved the transponder and ELT. Both of these boxes receive position info from the GPS-175 via serial data; for the ELT this allows for a more precise emergency transmission, while for the transponder the GPS-175 data is required for ADS-B compliance.

Of course, doing either one of these requires that the GPS-175 actually have a position. And while the Skyview system was eventually able to get a position fix even inside the hangar, I’d had no such luck with the 175. I decided to give that a try tonight, leaving everything up and running for over 30 minutes, and it still didn’t work out. That’s not too surprising, but kind of a bummer for testing purposes. I’m considering figuring a way to roll the fuselage out onto the ramp just so I can test this, but I’m not really sure of a good way to do it right now.

Anyway, while I was letting everything run, I did install the fuse for the transponder and get that set up with the Skyview system, though of course it complains that there’s no complaint position source. I also inadvertently verified that the ADS-B receiver worked, since I saw some traffic appear on the display while I was poking around at other stuff.

I also got to looking at the tail, thinking of routing the tail strobe wire. I temporarily reinstalled the elevator push tube so I could get an idea of potential interference, and I think I have a good idea how to approach this routing now. Originally I was thinking I’d have to route it through the forward bulkhead hole the push tube goes through, which was really bothering me, but it’ll be a lot smarter to just drill a hole in the bulkhead with a snap bushing – this should keep the wire well clear of the tube.

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