On Friday, May 11, 2018 at 2:10:14 PM UTC-7, Steve Cameron wrote:
I've recently bought a glider that has an older Becker transponder(mode c), and every time I turn it on it invariably displays the E10 error code. In reading past reports of this issue(2006/2008) on the net this seemed to be a fairly common occurence, with no real solution. Becker says its a transmission fault involving the antenna and or ground plane. My local avionics shop tested it for the two-year cert, everything checked out OK, than at the end of the check the E10 pops up. We've tried adding a short piece of coax at the antenna end, as well as insuring the ground plane is truly grounded. So far nothing seems to rid the error message. My avionic tech here seems to think it was a design flaw in the unit, and I'm very tempted to just scrap it and move on. Is there anyone out there who has successfully dealt with this issued?
Thanks
SC

What Becker transponder model? A 4401 for example in working order with encoder seem to go for ~US$600, a Becker TT22 (the only new transponder I'd buy for a glider today) is ~$1,900 so that gives you a repair cost range to work with. Assuming you are in the USA, Becker service here has been pretty good with quotes and turn around in the past.

What exact antenna and what ground plane? Carbon of fiberglas fuselage?

Does it only happen on the ground? What surface is the glider/antenna over when this happened. Does it happen when you are flying? It may be a spurious error from ground reflections. That is one suspect in Becker E10 errors.

If the problem is happening on the ground a simple test is to jury rig a whole new coax cable from the transponder to the antenna and repeat what caused the problem.

I suspect a common cause of the E10 error is coax cables, especially faulty coax connectors. The only time I've seen that it *was* a faulty coax connector. Screw together coax connectors can have more have problems through handling. And corrosion can get into connectors. Much more likely an issue than the ground plan itself or it's connection between the ground plane and its coax connector. Always suspect the connector at the unit as it gets handled/abused most.

It its a rod/ball antenna give the rod a gentle tug, I've seen those broken out and uh pushed back in.

If the tech thinks the Transponder is faulty they should pull it onto their bench and test it there.