Little Dipper Posted April 10, 2018 Report Posted April 10, 2018 Yesterday I lost both weathers (fisb and XM) on the Garmin 650 & 750. There was substantial icing conditions. Do any radio experts on this list know if iced up antennas could have caused that issue? 1
exM20K Posted April 10, 2018 Report Posted April 10, 2018 Probably. I believe they are placarded against painting for the same reason.
thinwing Posted April 10, 2018 Report Posted April 10, 2018 Maybe....the no paint prohibition is due to many paints contain metallic pigments that block radio waves.Ice can be a factor but also the static charge buildup from precip.Losing fisb is a puzzle..that signal ,being ground based is much more powerful ..My antenna is on the belly and is just a transponder antenna...
EricJ Posted April 10, 2018 Report Posted April 10, 2018 It certainly doesn't help, but whether ice was responsible for the failure would be difficult to determine. If there's ice build-up there may be moisture intrusion in the attachment or electrical connection, and that doesn't help, either. Ice both reflects and attenuates rf energy, but specific effects on a particular antenna with a particular level of build-up at a particular frequency in a particular direction would be tough to guess. But, yeah, it doesn't help.
Seth Posted April 10, 2018 Report Posted April 10, 2018 In light icing over West Virginia in 2009. my former 1967 F model, I encountered icing for the first time of my flying career and lost radio communication with approach control for a short period of time until I was in warmer air. This was not GPS or WX, just normal Com 1 at the time which was a KX-155. -Seth
Piloto Posted April 10, 2018 Report Posted April 10, 2018 (edited) Antenna icing susceptibility depends on the antenna type. Bare wire antennas are the most susceptible ones. They essentially get shorted to ground when ice covers them at the base. Least susceptible ones are the ones with the radiating element encapsulated (blade antennas). For patch antennas like GPS or XM/WX and COM blades is best to apply Rain-X before the trip to reduce the possibility of icing. Airliners have heated air conduits antennas. José Wire Antenna Encapsulated Antenna Edited April 10, 2018 by Piloto 1
carusoam Posted April 12, 2018 Report Posted April 12, 2018 Nice pics, LD! Thanks for sharing. Best regards, -a-
TomR Posted April 12, 2018 Report Posted April 12, 2018 Yep I’ll second what everybody else has said. If your antenna is bare wire any ice could change the inherent gain of the antenna or worse yet short it. However any ice on any antenna is going change it’s gain and potentially cause multi path problems. GPS tend to be most susceptible to this because the received power is quite small. Long story short unless you can actively de ice an antenna, any conductive material near the antenna is going to cause interference.
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