The rules spell out the verification and who may do them. The tests are
in
Appendix E and F of Part 43.


First, I should point out that I DO care that the altimeter, and mode-C
agree, and are correct. That's actually more important to me than whether
it's legal, and there are simple ways to verify this, without having a
signature from an avionics shop.

I've been reading through appendix E and F, and the best I can tell, I can
take the transponder and encoder to an avionics shop, and have them bench
tested. This should be legal, though still absolutely meaningless, since my
wiring and antenna are still unknowns. Realistically, the only thing that
matters is having ATC confirm the readout, and having a formation aircraft
confirm my altimeter.

I'll call the avionics shop tomorrow and see if they agree to this plan.
I'd already be willing to wager that they won't.

Thanks,
Rusty