Originally Posted by alctel
I've choked all the wires leading to the autopilot
(there are a lot of them) and it's still happening - would it be worth putting the autopilot
computer unit into a metal box and seeing if it still happens? If so, would steel
Yes, you can try that. It needs to be a box and not just a cover. The least expensive approach may be to buy an appropriately sized "project box" from an electronics
supply house. Steel
are fine. I'd test it before painting or applying other coating. Ground the box. The problem is that if your autopilot has an integrated flux gate compass
you're going to generate new problems.
On the other hand the problem may be an external flux gate compass
. You may have to relocate that or reroute the cable between the flux gate compass and the autopilot computer.
Originally Posted by Paul L
Is your antenna cable from the radio
to the antenna tuner run clear of all power and instruments
wires, Ie not in the same cable runs or near? If it has to cross a cable it should be at right angles and not run close and parallel.
This is a bit of valid conventional wisdom that leads to great frustration. Sometimes you simply can't. You have to do the best you can. As much separation as practable and shielding may be the best you can do. That certainly works on most boats.
Originally Posted by Brian.D
I already mentioned common mode currents as a culprit. You need to choke the source, not the destination
. Get yourself a choke balun from balundesigns. This will prevent any stray currents from getting into your system.
For less than half the cost you can buy six or seven type 31 ferrite beads and heat shrink over them at the tuner end of the coax between radio and tuner. This duplicates the deservedly well regarded RadioWorks coax isolator. This approach also avoids two additional connections in the coax.