Thanks for the info Mark On Fri, Feb 26, 2021 at 3:42 PM Mark Langford via KRnet < krnet@list.krnet.org> wrote:
> A couple of months ago I flew down to my father's farm to survey some > recent storm damage, and while orbiting the place to take pictures, I > heard the local Army ATC warn a helicopter about my position. The > helicopter said he didn't have me in sight, and ATC replied that I had > my transponder "turned off". This was pretty alarming news, and when I > got near home I requested HSV approach to verify they had my position, > and they couldn't located me, even with IDENT! I subsequently requested > a PAPR ADSB performance report (as I usually do after each flight), and > discovered that "baro alt" was 100.0% failure! The previous flight had > a high percentage of baro alt failure, but was usually 100% pass on > previous flights. > > So this was quite sudden, and I couldn't imagine why, but I went through > the echoUAT setup and verified everything was correct, as well as > checked out the wiring and mounting, making sure nothing was > disconnected or shorting the antenna. I even swapped the antenna with a > known good one and went for another flight....same 100% failure rate. I > also checked the antenna cable, using an ohm meter to check for > continuity and shorts, and it was fine. I couldn't swap the cable out > to check it because of the weird combination of connectors on each end, > nor did I have a proper tester for it anyway. > > The Becker transponder appeared to be working properly, complete with > displaying my baro altitude in the display just like it always did. But > I got no interrogation indication, so assumed something was wrong with > the transponder....so I sent it out for repair. They ran it all day > long on their test equipment, and said it was fine, suggesting I check > my antenna or antenna cable. I found this hard to believe, as this > antenna cable was professionally made, and was only a few years old, but > I ordered another one (and custom cables with different connectors on > each end are not cheap)! After replacing the cable all subsequent > flights have been 100.00% pass! > > I'm not sure of the moral of this story, but don't rule out all > possibilities when troubleshooting this kind of stuff. I'm also quite > impressed with this Becker transponder, as it's worked flawlessly for 15 > years now. The previous transponder, a Terra, croaked early because the > antenna connector worked itself loose, and apparently fried the output > stage due to a lack of "load". Something else to worry about.... > -- > Mark Langford > m...@n56ml.com > http://www.n56ml.com > Huntsville, AL > > _______________________________________________ > Search the KRnet Archives at > https://www.mail-archive.com/krnet@list.krnet.org/. > Please see LIST RULES and KRnet info at http://www.krnet.org/info.html. > see http://list.krnet.org/mailman/listinfo/krnet_list.krnet.org to change > options. > To UNsubscribe from KRnet, send a message to krnet-le...@list.krnet.org > _______________________________________________ Search the KRnet Archives at https://www.mail-archive.com/krnet@list.krnet.org/. Please see LIST RULES and KRnet info at http://www.krnet.org/info.html. see http://list.krnet.org/mailman/listinfo/krnet_list.krnet.org to change options. To UNsubscribe from KRnet, send a message to krnet-le...@list.krnet.org
