Earl,

I've never come across noise problems to the extent that you
are expecting. I wouldn't go spending alot of money on filtering
until you find a problem bad enough to warrant it. Specifically,
I've never had any problems with instruments and VHF. I do get
some noise from the inverter into the SSB. The inverter is running
the computer but I can just turn it off and let it run on its internal
battery. The noise is only a problem when picking out weak stations.

A ferrite bead is just a collar of ferrite that clamps around a wire. They
filter out any noise that may be induced in the wire. I have them
in some of the wires leading to the autopilot modules. The power leads
to the SSB and the computer. They only cost a few bucks each.

Doug
s/v CAllista

"Earl Haase" wrote in message
...
Doug,

Thanks for the response. All the instruments I am installing are new.
They are going on a 1970 Chris Craft that is nearing completion of a
four year restoration. I am looking at filtering to avoid problems
before they start. The boat is in Tampa and when I get it in the water
I will be leaving to take the boat back home to the Caribbean. I will
not have time to play with things very much before leaving so I want to
fix it before it breaks. The only shake down will be as I cross the
state to the east coast through the river & canal.

Tell me more about these ferrite beads. An Autohelm autopilot I have
(will not be part of this installation) included installation
instructions to use them. The instructions did not go into detail on
why they insisted I needed them.

Thanks again,

Earl