vhf vs depth finder

[gt]

19' Alumacraft Trophy. Console space is tight. I want to mount a vhf, but if I mount it where I want, it will only be a few inches from the depthfinder. If I mount the antenna on the opposite gunwale, it will be 7' from the depthfinder. Will I still have interference. Is it more important to keep the radio or antenna away from the depthfinder?

Thanks,
Gary

 

[Art Bernard]

Re: vhf vs depth finder

I don't think it matters since the transducer is mounted on your transom and below the waterline and that is where the signal for the depth finder comes and goes. I wouldn't think RF energy would interfere with sonar signals anyhow.

Art

 

[Fireman431]

Re: vhf vs depth finder

From what I've experienced, the only interference you may see is during transmission over the radio, not reception. In the event that you get interference, are you really that dependent on the depthfinder for the 1-2 seconds you're transmitting? (if there is interference at all?)

 

[dingbat]

Re: vhf vs depth finder

From what I've experienced, the only interference you may see is during transmission over the radio, not reception. In the event that you get interference, are you really that dependent on the depthfinder for the 1-2 seconds you're transmitting? (if there is interference at all?)

I agree, but this is one of those things that points to an even bigger problem.

If you're picking up interference on a display from a VHF transmission you have a problem in our elecrical system that needs to be addressed.

 

[gt]

Re: vhf vs depth finder

Thanks guys, but I'm more concerned by interference on the radio, from the depthfinder... Currently carry a handheld (Icom M-72). If I lay it down to close to the depthfinder, I get weird noises on the radio, and have to turn the squelch suppression way up... to the point I miss some normal reception..

 

[Splat]

Re: vhf vs depth finder

Ahhh yes.... cheap Chinese crap that leaks rf like a broken umbrella. The nemesis of ham operators. You'll prolly be ok with the antenna on the other side. That's where it should be to comply with rf exposure limits anyways. You can always temporary set up your station and check for interference.

Other things that will help with rf noise it keep your radio power cables away from transducer cables. You could even try a few ferrite chokes if you have any problems.
73's
Bill

 

[Boatist]

Re: vhf vs depth finder

I have interference on my VHF Channel 72 that comes from the
192 khz from the depth finder. I called Lowrance right after I got Depth finder and the first guy said make sure none of the power cables run in the same bundle back to the battery. The units are about 2 feet apart. Next I sent them a letter so I would have it on record and one of the tech replied back to me.

He said he had been working on the problem for some time and the interference was coming from the depth finder head unit. They tried shielding the Fish finder but made very little difference. Their final reply was the interference was coming from the screen of the depth finder and they have no solution. So I put some foil over the screen and attached to a 1 inch Ground brad back to the battery and it did solve the problem. Since can not see screen cover in foil I just do not use channel 72.

On mine if I turn the squelch up on the radio the noise goes away but when someone talks on 72 you can still here the noise in the background.

If I Stop the ping from going out the all channels work.
In my case channel 72 is one that I don?t use much so just took it out of my channel scan.
Now my Lowrance unit was a 1985 unit.
I would sure contact the maker of your fish finder and tell them of your problem. Give them as much detail as you can and see if they have a solution. Never hurts to tell them that you have been discussing in boating forums and no one has been able to help. They may not admit they know of the problem but still give you some options. None of them want their name out in public with a problem discussion that will hurt sales.

 

[Art Bernard]

Re: vhf vs depth finder

I was re-reading this post and another thought occured to me. You can look at this from a car stereo point of view. You can run all power lines down one side and all other lines down the other, also you can get mu metal shielding to wrap the cables and that will isolate and prevent leakage form one system to another.

Art