"Roger Conroy" wrote in message

Got bad news for you... A homebrew an aviation band transmitter is
illegal.

Of course it is - and well it should be!!! I'm interested in the design
problems involved. If the results showed that something new, novel
or at least in the "better bang for the buck" category could be
constructed *and* it appeared to be of some interest to others I'd
seriously consider going to the trouble of FCC, FAA, TSO, RTCA,
NMEA, STC and whatever other relevant "LMNOP" alphabet
drills may be required. But that's quite a ways off and for now this
is more of an academic exercise than anything else, mostly because
I'm stunned at how little information is actually available. It's a
challenge.

And also you have to be a pilot or air traffic controller to operate an
aviation band transmitter - such transmitter must also pass specified
standards to be legal for use.

As noted above.......

I can appreciate you advising caution - but as I previously mentioned
(in the original post) I'm well aware of the potential "problems".

A reciever is a different matter of course.
There are quite a few manufacturers that make aviation band reciever kits.

But a real shortage of truly well-executed examples - or kits that happen
to satisfy my desired set of performance/features.......8-) I've already
built a 'couple - and then shredded them one functional block at a time so
that, eventually, the result is virtually a clean-sheet design. Sure, it's a
lot
of trouble - but entertaining...........8-)

Bill