iFly GPS Forum

I am planning to fly from the SF Bay Area to Bend, OR this weekend, but this time in the C-182 (which I now have the external antenna set up). I will play around with my Verizon phone on and off to see if that impacts the very random Altitude alerts.

I have sent a report into the AP staff. Flying my C-182 up with the iFly on the yoke, and the external antenna on top of the panel, I was still getting the random altitude alerts. It did not seem to make a difference if my Verizon Blackberry was on or off. We are investigating any other possible sources of interference. I am talking about getting one event every 20 - 30 minutes on average that last a few seconds. I am seeing about the same thing in my Grumman Yankee, mounted on the yoke without the external antenna.

No, nothing new on this front. I fly two aircraft mounting the 720 in Portrait mode on the yoke. The issue seems to happen with some regularity in both planes. In my 182 I use the external antenna on top of the panel. In my Grumman AA-1B I have not been using the external antenna, but it is under a bubble canopy and looks like it gets good signal. Not much in common in avionics, my 182 is mostly King, KX-155 and 170B, but a Bendix Transponder. My Grumman has a Narco Mk-12D and a King KT-78A transponder.
Some things I have not tried, moving the antenna in the 182 away from the panel.
Orientating the GPS back to Landscape mode in the Grumman (antenna orientation may help).
I have thought about trying to rig up my old HP Spectrum analyzer to look at the output of the antenna in the 182, but since the (heavy) battery inverter for this unit died some 15 years ago, I no longer have a way to power it in the plane.
And to monitor the analyzer would require another person in the plane.
If anyone has any suggestions, I will consider them.