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  #1  
Old 04-07-2009, 11:20 AM
vonjet vonjet is offline
 
Join Date: Feb 2008
Location: Thousand Oaks, CA
Posts: 183
Default Trutrak Digiflight IIVS question

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?
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  #2  
Old 04-07-2009, 11:45 AM
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Geico266 Geico266 is offline
 
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Default

It must. When I keyed my mic the oil pressure shot up 40 PSI.....until I moved the wire away from the coax.
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  #3  
Old 04-07-2009, 12:11 PM
TrutrakTech TrutrakTech is offline
 
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Default RF Interference

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.
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  #4  
Old 04-07-2009, 12:21 PM
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pierre smith pierre smith is offline
 
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Location: Louisville, Ga
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Default An earlier poster had problems....

....while he was in the hangar. It was suggested that RF could be bouncing off walls, roof, etc and to take it outside.

Regards,
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  #5  
Old 04-07-2009, 12:23 PM
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scard scard is offline
 
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Default

Also, be aware that funny things happen with RF inside the garage or hangar that very well may not occur outside.
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  #6  
Old 04-07-2009, 01:18 PM
breister breister is offline
 
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Location: Atlanta, GA
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Default

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 on the TruTrak forum. $20 has provided a solution to RF/AP interference in a few reported cases now.
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  #7  
Old 04-07-2009, 03:33 PM
vonjet vonjet is offline
 
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Location: Thousand Oaks, CA
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Default Thanks

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.
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  #8  
Old 04-08-2009, 08:03 PM
N91CZ N91CZ is offline
 
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Location: Woodland, CA
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Default

Quote:
Originally Posted by pierre smith View Post
....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.
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