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View Full Version : Trutrak Digiflight IIVS question


vonjet
04-07-2009, 11:20 AM
I have not even set up my autopilot yet but it is installed. I turned it on today and the heading said 125. I keyed my mic and the heading swung pretty large like 40 degrees. Does this mean I the wires to the servos are too close to my comm antenna cables?

Geico266
04-07-2009, 11:45 AM
It must. When I keyed my mic the oil pressure shot up 40 PSI.....until I moved the wire away from the coax.

TrutrakTech
04-07-2009, 12:11 PM
You are definitely getting some strong RF interference into the AP to affect the azimuth gyro. Try moving your comm antenna wires as was suggested by Geico266. Let me know if you have any further trouble.

pierre smith
04-07-2009, 12:21 PM
....while he was in the hangar. It was suggested that RF could be bouncing off walls, roof, etc and to take it outside.

Regards,

scard
04-07-2009, 12:23 PM
Also, be aware that funny things happen with RF inside the garage or hangar that very well may not occur outside.

breister
04-07-2009, 01:18 PM
Most folks who see something funny happen on the TT autopilots experience pitch, not heading, problems.

Make sure you use the latest recommendation for coax (RG58 is no longer considered the right choice); run your antenna wire away from other wires if possible; make sure you have good grounds; etc.

If you still experience problems after all of that, you might check out this thread (http://trutrakap.com/forum/showthread.php?t=43) on the TruTrak forum. $20 has provided a solution to RF/AP interference in a few reported cases now.

vonjet
04-07-2009, 03:33 PM
I ordered that part from Digikey. Thanks for the link. I am going to pull my comm coax out of the bundle and try and separate it from the other wires which is very hard considering the amount of space I have.
I really cant understand why the guy that wired my airplane, which has done many lancairs, bundled all my coax cables along with everything else and still claims he has never had a problem doing it this way. :confused:

N91CZ
04-08-2009, 08:03 PM
....while he was in the hangar. It was suggested that RF could be bouncing off walls, roof, etc and to take it outside.

Regards,

It does. I've measured the VSWR, as well as, the transmitted and reflected power directly, both inside and out. The difference is quite dramatic.