CB noise

[BGGB]

hey all, i recently installed a cb on my 65 and was excited to have a distraction from all the rover noises, but when the engine is running all i get is a buzzing noise that follows the rpms. it works fine when the engine is off. i tried running leads striaght to the battery thinking that it was picking up interference from the grounds or something but it didn't work. i replaced sparkplug wires also thinking they might have been leaking some electicity. if anyone has experience with cbs and thinks they can help it would be appreciated. also if you could list your cb and antenna combo. as always thanks

[navydevildoc]

Some troubleshooting first...

If you disconnect the antenna and start the truck, do you have the same amount of noise, or less than when the antenna is connected?

If the noise drops without the antenna, you are picking up ignition noise. If the sound stays the same, it's coming from your power source. Since you say you ran wires directly to the battery, you should have eliminated any ground differential.

You say you got new spark plug wires, were they specifically shielded for RF noise?

Once you have an idea of where it's coming from, you can figure out how to proceed!

[Terrys]

Sounds like you're still running a generator (as opposed to having switched to an alternator) Since generators make a noise more like buzzing than alternator whine.
You might try finding some old "Hash Chokes" which are combination of an inductor, and a capacitor. They were commonly used back in the 'generator days'.You can also try a .01Mf, 50VDC capacitor on the heaviest of the two posts on you generator.

[BGGB]

thanks for the fast response, i just when outside and pulled the antenna from the back and the noise didn't change at all. i don't beleive that the wires were special, they were new blue silicon wieres. i do have a generator still (hopefully a negative ground alternator conversion soon) can you get the capacitor at radio shack? also the radio has noaa weather channels that work fine when wheather the engine is running or not. thanks again guys

[navydevildoc]

thanks for the fast response, i just when outside and pulled the antenna from the back and the noise didn't change at all. i don't beleive that the wires were special, they were new blue silicon wieres. also the radio has noaa weather channels that work fine when wheather the engine is running or not

Then it sounds like power... do you still have a positive earth system with a generator, or has it been converted to a negative earth with an alternator?

Also, regarding NOAA... the frequencies for NOAA are wayyy above CB, in fact they are higher than FM broadcast radio.

[BGGB]

i still have the generator and possitive. terry was saying that i could try a capacitor on the generator

[navydevildoc]

i still have the generator and possitive. terry was saying that i could try a capacitor on the generator

Well, then the interesting question comes up... did you happen to stumble on to a positive ground CB? Or have you ensured that the entire thing is isolated from the frame/chassis/body? You have connected straight to the battery, but if the radio is expecting ground to be negative, there could be circuitry going haywire in there.

But, the fact that you are getting the NOAA radio OK would suggest you are OK.

Terry's idea might work, I don't know... but worth a shot!

[BGGB]

when i got the radio it had directions for wiring it up poss or neg so i think that should be alright. do you think it could still be in my wires, i don't think they were made to block rf but i really don't know. Thanks