VHF/DF Interference

[Wild Bill]

Dealer installed ICOM 502 VHF, with Digital 528-VWF 4', 4.5 DB antenna and Lowrance LCX 104C combo. The install is very neatly done. Everything works as it should, but when the depth finder is on, the VHF has noticeable interference. With the DF off the radio reception is very good. Since I normally turn the DF on in the beginning of a trip and leave it on, this makes a fine radio and antenna not work as it should.

I will ask the dealer to try to improve it, but would like to know what the remedies may be. Would routing a wire for either the VHF, or DF power directly from the battery with an in-line fuse instead of using the fuse block help? Is there any type of noise suppresser that can be added to a VHF radio?

[HOTSPOT]

This is normally a grounding issue. Be sure all equipment is commonly grounded. Another cause is the coax connector not making a good connection. I talk to a lot of guys on the radio. Probably 60% of the time, when they are transmitting, I here the FF interference or clinking sound. I had this same issue with one several years ago and it was the connector on the coax, replaced it and it worked perfectly.

[Wayne Tj]

I agree, make sure that you have good grounds to both units and double check that the antenna connection is solid. And most importantly, make sure that you do not run the transducer's cable near the antenna's cable or the VHF's power leads.