Dynon 180 altitude error

[dothetime]

I just installed a ADS-B system, FAA reports that my altitude
Shows momentary spikes of altitude to
30k feet, while I am at 2k
Suggestions please, I am using a Garmin 327
And a Skyguard ADS B and the D180's encoder

 

[dynonsupport]

What makes you think this is the D180's issue? Altitude in ADS-B comes from GPS as well, which is internal to the Skyguard. Have you sent your report to Skyguard and asked them what the root cause of the issue is?

Are you using the Dynon altitude encoder converter, with 15 wires hooked to the 327 and Skyguard, or a serial connection to both?

When was your last bi-annual transponder check? Did you do one after you added the Skyguard to the transponder encoder line?

 

[dothetime]

I'm not sure where the problem is yet. I have sent the report to skyguard also, waiting for reply.
I am using the Dynon altitude encoder wired to the 327, the skyguard picks up the info from the garmin wirelessly with a built in squawk detector. Last txponder check was in December, passed. An additional check was not done, the skyguard is not wired to the txponder as I said. Thanks for any suggestions you may have.

 

[dothetime]

The report stated that the jump to 30 k was pressure altitude, not gps altitude.

 

[dynonsupport]

Sounds like you're hooked serially to the 321. If that's true, there's no way for that signal to be messed up if it's working at all. Unless your D180 is showing 20K feet on the altimeter now and then, it's not the D180 to 327 link.

The Skyguard would only need to read one bit from the transponder wrong for that to happen though. I think you really need to work with Skyguard.

 

[dothetime]

Thanks for your input, I appreciate it.
Dave