On Jan 2, 6:15*pm, Dave Nadler wrote:
A handheld transponder would be an extremely bad idea !

Get a TRIG transponder, Mode S.
Put a stub antenna somewhere in the back pointing
down aft of the gear, with ground-plane above and inside.
Use the proper and expensive coax for the antenna;
this is not a radio shack nor shade-tree job.
Really best to get a proper radio shop to do the install.

Can't help you with a 337 but a good radio shop can.

Hope this helps,
Best Regards, Dave "YO electric"

The problem is that the "good" radio shop won't want to do install
without having "approved data" to follow.
Schweizer needs to do a modern battery installation drawing for folks
to follow. The existing one is for a lantern battery.
UH