Vhf radio interference

[Frank mellin]

I have a vhf radio fitted on my freeman cruiser and recently fitted a fish finder which works fine but when it goes into
Scanning mode it interferes with the vhf radio.
I fitted some small devices in the aerial lead which are supposed to stop interference but they do not work.

 

[st599]

Presumably some form of ferrite choke?

The interference can enter via any cabling or, if powerful, via the case. You may need to try a choke on the power leads

 

[andsarkit]

Agree with st599. Get some ferrite chokes (available on Ebay) and clip around the power leads of both the fish finder and radio. You might find that these are already fitted. You can fit a larger one and loop the cable through several times for more effect.
Keep the power cables separate if possible and not running alongside or if crossing they should cross at right angles.
Keep the antenna coax clear of any other power cables and if the radio has an earth point check it is connected.

It is very much trial and error but the components are cheap to try out.

 

[wonkywinch]