I have an old Cetrek P770 autohelm which operates perfectly. For a long time I
have experienced interference in my VHF radios (both DC and handheld) when the
unit is operating. Previously it was an annoyance, but since I installed a
better and more sensitive VHF the situation has become less tolerable.

I am about to write Cetrek, but groups like these are much more responsive at
times. Here's the info: The interference is a pulsed white noise (not
precisely like 'motorboating', a well known type of interference). I had a
radio/computer/antenna guru, ex-professor now working for HP, look at it. He
didn't have any answers but was most impressed that the interference 'broke
squelch'. Perhaps if I'd had an electronic schematic of the units he would have
had better luck.

Strong signals are able to be heard with no interference, weaker ones with some
interference heard, and some even weaker station signals are broken up into
packets by the interference. Simply listening to near signals isn't always an
option in two instances: A) When operating in remote areas (Desolation Sound)
where even the Coast Guard's signal may be weak, and 2) When operating in areas
where use of low power communications is either mandadory or prudent.

I would appreciate hearing from anyone who has had a similar problem with any
unit, or anyone with knowledge of conditions like this.

Chuck