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Old May 14th 18, 04:33 AM posted to rec.aviation.soaring
AS
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Default Becker Transponder E10 error message

On Sunday, May 13, 2018 at 12:05:00 AM UTC-4, Darryl Ramm wrote:
On Saturday, May 12, 2018 at 7:33:35 PM UTC-7, AS wrote:
/snip/
Steve,

my 4401 has a threaded BNC connector in the back. I bought a new threaded-to-bayonet adapter to make sure I have a good and rattle-free connection..
As for the ground plane, I have some 'real estate' behind the seats and installed a ground plane about 1.5ft x 1.5ft. The guy who did my transponder check and sign-off liked it.

Uli
'AS'


I'm not sure this really great advice. Sure it seems to work, but you are adding unneeded complexity to the RC coax signal path. The reason that many transponders use a TNC not a BNC connector in the first place is that TNCs are better connectors at the 1 GHz frequencies that transponders operate at. If something appears too loose then possibly the TNC plug is not correctly installed on the coax, and then maybe the BNCs are not either but just "feel better". I'm more concerned here that there was possibly some bad coax terminations happening that needed to be worked around. And it's just an unnecessary extra connection that may have problems.

Connection quality at 1 GHz is more critical, and less forgiving, than say the many sins you can get away with at VHF radio frequencies. And sure it might work fine, but you don't really know what little things like unneeded adapters or possible bad cable terminations are costing you in output performance.

I would really encourage everybody to try to follow manufacturers install inductions. Those install manuals describe the proper TNC coax connector and coax cable to use. It is important to use specific convectors designed to mate with the exact coax type (or in some case exact brand/cable version) you have. If things are not fitting properly that may be the problem. Tolerances for all these connectors are pretty tight, and it takes practice to terminate a coax really well. Have a pro do it for you, or better show you how to do it. Even coax that looks very similar may require different coax connectors and crimp tools/dies (if they are crimp on... and crimp is usually the best *if* you have the right crimp tooling,... which may get unjustifiably expensive for occasional work.).

BTW I was just reading the Trig Europe EASA minor change install documentation for gliders, https://www.trig-avionics.com/librar...2X.002-4.0.pdf and there is good stuff there as well as in their standard install manuals. Becker documentation is usually great as well.

And an aside: In some respects passing the transponder RF check is a pretty low-bar.... it will find gross errors--and in the post that started this thread it sounded like the transponder passed the test but then failed itself with an E10 error. Those tests come from the distant past where a large part for them, and certainly the biannual checks was detecting degradation of traveling wave tube based transponders. And maybe with solid state transponders the test period for RF tests should have been increased..


Thanks for the reply and additional information, Darryl! I did look for a co-ax cable specified by Becker with a TNC on one end and a BNC on the antenna end but couldn't find one in the required length. Should I see any issues creeping up, I will ask the avionics guy, who did the sign-off to make up a custom cable.
Uli
'AS'