noise in VHF MARINE RAIDO

When I turn on my Depth Sounder I get a noise on my VHF MARINE RADIO. I think it is from the sending device that measures the depth of the water. Does anyone know how to fix this?<br /><br />Thank You<br /><br />The Sea Dog

Re: noise in VHF MARINE RAIDO

Radio shack.<br /><br />You can get a noise suppressing filter there. They are anywhere from $15-$50. A middle of the field should do it for ya.<br /><br />Oh, and welcome to the forums.

Re: noise in VHF MARINE RAIDO

do they share the same power lead?

Re: noise in VHF MARINE RAIDO

You need to determine of the noise is getting in via the antenna or the 12 volt power line. I suspect the power line since the sonic frequency is very much lower that the radio.<br /><br />Disconnect the VHF antenna and move it away from the radio, see if the noise goes away. If so, you are getting radiated noise into the VHF and you will have to try moving the VHF antenna or the source of the noise further away.<br /><br />If you still have the noise, it is coming in via the 12 volt line. some suggestions for power line noise redution include twisting the 12v wires and running them directly from the radio to the battery or another "strong" source like a 12v bus.<br /><br />A noise supressor can also be used like 'dude suggested.<br /><br />Good Luck<br /><br />Tony

Re: noise in VHF MARINE RAIDO

An additional thought for you, does the sounder transducer line run anywhere near or alongside the radio power cable?<br />I just ask because I had that problem and it was resolved only when I ran the sounder transducer cable down the opposite side of the boat from all the other cables.<br />Ross

Re: noise in VHF MARINE RAIDO

Maybe I can help a little bit, but with generally the same recommendations, but maybe a little bit more.<br /><br />The first thing I would do is filter the power supply for the radio, not the fish finder. You can to to your local friendly Radio Shack and head for the wall where there have the auto stereo stuff and look for a bubble wrap noise filter of 20 amp capacity. I believe they get about $18 for one of them. I had one around here somewhere just last week to get the catalog number off of it for a guy who was having the same problem as you. Give me a yell if you need it.<br /><br />The next thing to do is take a good look at the connector on your antenna cable. Very often a problem with the soldering of the PL-259 connector will allow the introduction of static from the fish finder. What can be even worse than what you are hearing from the fish finder is what you will hear if a LORAN comes anywhere near the thing. If you are not well experienced in soldering them on you might want to give it a very good look and maybe just replace it with one of Shakespeare's "Center Pin" solderless connectors. They work ver well.<br /><br />You should also check the rest of the coax cable for any large nicks or cuts in the insulation. If you find any cut the cable back (you can extend them using the proper connectors if you need to) if you can or replace the antenna if you can't. Do the same thing with the power wires and then make sure that the cable from the transducer to the fish finder is not routed such that its in contact with either the antenna's coax cable or the radio's power wires. If you do those things you should fix it. There is another type of electrical noise that comes from the engine and that is the one to really worry about because its so hard to track down and fix, but what you've got should be an easy saturday morning fix.<br /><br />Thom

Re: noise in VHF MARINE RAIDO

I have found that many boats will emit interference with VHF frequencies. Weather it be from the depth finder, trolling motor, or other device.<br /><br />I pretty much depends on the radio and the fish finder, as My different radio's will react differently with different boats close by. <br /><br />I think it just has to do with the quality of the receivers circuitry, and sensitivity, or selectivity.<br /><br />Try omitting that frequency that acts up from your scanned channels.<br /><br />Turn up the radio squelch.<br /><br />But what you might find best is a different radio, perhaps with better selectivity in it's specifications.<br /><br />Heck,....<br /> I recently bought a Humminbird VHF handheld for $69 new, and it works quite well out on the water. But try it at home and with all the different interference sources around the house there's only a couple of channels left it will scan without making a bunch of noise.