Fluttering Sound (Interference) in VHF Radio While Engine Running

Head Lice said:
Have a pair of ICOM radios. Installation instructions for both say to ground directly to the battery with a fused lead. Question: Why a fused negative/ground?
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It's really not needed. The theoretical reason is something else may not be grounded properly which could theoretically cause excessive current pull from the radio's ground wire but in reality that'd be a pretty rare situation. Especially in a TJ.
 
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SSTJ said:
Great to hear, thanks. Yes, I have a hand-held that I could set to 5W, which is about the same as my CB, right?

In the meantime, here are pics of my antenna ground. Although it's hard to tell in the pics, I can confirm that the ground strap is contacting bare metal, where I scraped the paint away with a wire wheel. Same is true on the underside of the antenna mount, where the coax comes up to the mount.

View attachment 394245
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Did you get rid of the powder coating and paint in all areas touched by things that need to be grounded? Everything that needs a ground requires a bare-metal connection everywhere, including where the ground strap is bolted to the tub. And when an antenna has an installation problem like a poor ground and/or a bad SWR there can be odd problems here and there which could conceivably cause your odd sound.
 
Jerry Bransford said:
I'll still say 'never' if it's grounded directly to the battery in a vehicle. I've been involved in this stuff way too many years including when I made a living taking care of HF/VHF/UHF radio systems.
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And that's OK. But I've personally known of at least one situation where that long ground lead acted as an antenna resulting in a fair amount of QRM (for some odd reason). The problem went away when we grounded directly to the vehicle body with a short piece of braid. YMMV and all that - I wasn't lead tech on the situation, an "RF Guru" was.
 
Jerry Bransford said:
Did you get rid of the powder coating and paint in all areas touched by things that need to be grounded? Everything that needs a ground requires a bare-metal connection everywhere, including where the ground strap is bolted to the tub. And when an antenna has an installation problem like a poor ground and/or a bad SWR there can be odd problems here and there which could conceivably cause your odd sound.
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Yep, all bare metal. I'll try the SWR meter on 5 watts and see what I get.
 
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