Shoutout to the guy who helped me fix a glitchy GPS antenna on the ramp last Tuesday

I was out on the tarmac at KMDW trying to sort out a King KDM 706 that kept dropping signal on a Cessna 172. A mechanic from the next hangar over yelled out that it was probably a bad coax connection at the antenna base, and he was right - I found corrosion under the sealant. Has anyone else had luck just cleaning those terminals instead of replacing the whole antenna?

3 comments

3 Comments

fisher.jessica11d ago

Know I'm gonna be the odd one out here but I've seen way too many corrosion problems come back after just cleaning. You clean it up real good, seal it back, and six months later you're pulling the antenna again because the corrosion ate through the coax braid inside. That antenna base is a sealed unit for a reason. The corrosion you found means moisture already got past the gaskets and o-rings, and once that happens the whole assembly is compromised. I replace them every time now after chasing one too many intermittent faults on leased planes. Saves you the hassle of doing the job twice, trust me.

martinez.paul11d ago

Has anybody actually had a cleaned coax hold up long term?

samreed11d ago

Yeah @fisher.jessica is right, just replace the whole thing and be done with it.