VHF interferring with auto pilot

[jhunt4679]

I installed a SITEX SP110 autopilot in my boat and every time I key the mic on the radio it makes a hard turn to the right. The Mfg. suggested running separate power feeds back to the battery for each unit and I did that but still have the same problem. Any suggestions?

 

[KD4UPL]

Have you checked the SWR on your VHF antenna? Have you checked that both units are grounded well?
I suspect you're getting RF into the autopilot. How close together are the units mounted or how close is the antenna to the autopilot. Some separation might help.
Otherwise, I think you'll need to install RF filtering chokes on all the cables.

 

[jhunt4679]

No Title

Thank you for the reply but I think I found the problem! This mess was up inside the antenna mount, shield wasn't even connected. I don't know how I was getting 20+ mile range on the radio! Go figure the only thing I did not replace on the boat!!

 

[jhunt4679]

Ok so new antenna installed and still have the same problem. Any suggestions on the chokes to use?

 

[jhunt4679]

Even with the radio connected to a separated battery. Problem with the AP unit?

 

[jhunt4679]

It turns out it is a problem with the rudder feedback unit from Octopus! Si-Tex is sending the "Better unit" out. They received another call today for the same problem and determined it was the RFU. Turned the RFU off and the problem went away. Si-Tex is going to do some testing to see what the problem is. They said the RFU I have is very sensitive to any little voltage change. They do have great customer support! A whole lot better than trying to talk to someone in India!

 

[jhunt4679]

New RFU did not make a difference! I installed a ferrite choke on the cable and it helped a little but their fix is to move the radio as far as possible from the AP. Relocate my radio to the port side of the boat?!!!! I'm just about fed up with this damn thing!