last week we were happily cruising across East Texas in the Valkyrie, watching the autopilot take us to RV Central to work on the RV-1. Out of the corner of my eye, I was surprised to see the 430W annunciate that the GPS signal had become unreliable - then it went into Ded Reckoning mode. I have seen this during a series of aerobatic maneuvers, but never straight an d level! I of course, immediately switched to GPS #2 (and could have gone to #3, or #4...or heaven forbid, looked at the countryside spread out below, and the city ahead...), and figured I'd troubleshoot it on the ground.
Sure enough, the 430W picked up no satellites at all for the meaning 20 minutes of the trip, so I suspected an antenna problem. Lo and behold, when I reached into the oil door to check the firewall-mounted antenna, the screw-on TNC connector had backed off almost all the way. I am sure it was tight when I did the Condition Inspection before Christmas, so I'll have to chalk it up to vibration.
Interestingly enough, when Garmin went from the 430 to the 430W, they switched the antenna connection from a BNC (which requires two motions to disconnect) to the more expensive (and clearly less positively secure) TNC. No way to safety wire it that I can see.
Are your TNC's tight?
Paul
Sure enough, the 430W picked up no satellites at all for the meaning 20 minutes of the trip, so I suspected an antenna problem. Lo and behold, when I reached into the oil door to check the firewall-mounted antenna, the screw-on TNC connector had backed off almost all the way. I am sure it was tight when I did the Condition Inspection before Christmas, so I'll have to chalk it up to vibration.
Interestingly enough, when Garmin went from the 430 to the 430W, they switched the antenna connection from a BNC (which requires two motions to disconnect) to the more expensive (and clearly less positively secure) TNC. No way to safety wire it that I can see.
Are your TNC's tight?
Paul