Lot's of Noise when receiving...

[UtahGeneral]

So this is what I've got and how it's set up currently...I have a 64" stainless steel whip antenna mounted right in the middle of the roof of my 1976 Ford F150. The radio is one that I got from a buddy and is about 30years old probably. I have coax ran from the roof, around through the trim, and into the back of the radio. I have the hot and ground through the firewall and into a 45 amp noise filter a buddy at a radio shop gave me which then goes directly to the battery positive and negative.

Here is my problem - when I initially installed this set up I had it just wired into the fuse box (yes I know, bad idea). Anyhow, when set up that way I could transmit and receive just fine but as soon as the vehicle was running I got terrible alternator whine to where I could not receive anything.

After I changed the set up to how it is now it is a little bit better and when transmitting people say they can hear me just fine but when I'm driving I still get pretty bad noise on the line to where it is very hard to hear people talking to me.

A couple questions; Could this be SWR related? Could this be related to the radio just being very old? Could it be that my alternator is just REALLY old (as I'm sure it is) and is just putting out too much AC? Or is it just that I have no idea what I am doing w/ installing this? OR, some of everything? lol

Any help would be greatly appreciated!!!

[Red Warrior]

Could be a ground loop. Make sure the case of the radio is grounded to the closest metal. Don't rely on the coax or power return connection to provide ground.

[UtahGeneral]

Could be a ground loop. Make sure the case of the radio is grounded to the closest metal. Don't rely on the coax or power return connection to provide ground.

I have the radio mounted to the bottom part of my dash area which is all metal...is that what your talking about?

[231]

First off welcome to the forum.

To answer your question about SWR first, it's possible it's contributing to it, but not likely the entire culprit. A 64" whip is not resonant on CB band...not without a loading coil someplace on the antenna. Do you or any of your friends have an SWR meter you can simply check it? I've heard some guys who have complained of allot of noise that once their antenna was tuned, the signals over took the electrical noise and was much better...and usable.

Grounding the radio chassis to the dash with bolts isn't really a good connection unless you've used something like self tappers that really dig into the metal. Nuts and bolts don't ground well to painted surfaces.

I'd be more inclined to think you have several things going on. So the very first thing is to make sure the antenna is tuned properly and get that out of the way. Once that is done, start the truck and remove the coax from the back of the radio and see if the noise goes away. If it does, then the noise is actually being picked up either through the antenna and/or coax. Usually it's going to be the antenna. And if that's the case usually relocating it is the answer. But I'd probably try to go after the source before I do that.

If the noise doesn't go away much after unplugging the coax then certainly your filter isn't going to be enough. What I would do at that point is make sure you are running good resistor plugs and ignition wires and that both the ignition system and electrical charging system are in top shape. On the alternator, make sure all the wires and connections are in the best shape they can be in. Once that's done, invest in some snap on ferrite beads and start adding them to the power leads to the radio and alternator wires. That's just for starters by the way. The Ferrite beads I like to use are from DX engineering and aren't cheap. But they work. Radio Shack has some that works, but don't think that just one or two are enough. Get at least a hand full. LOL!

Last but not least is looking at the radio and it's short comings. You didn't list the brand or model, but some of the bottom end (and older) radios don't have very good filtering in them. Some of the better radios will have noise blankers that'll help significantly the noise. So now combine all of these things and you have a good start to go after the noise in both protecting the equipment from picking it up and hopefully helping stop it at the source. I'm sure there are more details to cover...but things like this I've always had the best luck going after systematically one thing at a time until it's fixed.

Just my thoughts on it. Hope that helps a little.

[UtahGeneral]

Thanks so much for your help - I was posting that last night from work and didn't have the radio w/ me and am at work again so don't have it w/ me again haha - Your advice is great and I'm going to hopefully have some time to work through all those in the next couple of days. I'm actually a police officer and our state radio shop guy said that he would call me this week and I could bring it in for him to tune the antenna and then we could work around the other possible grounding issues. Hopefully with his help and your advice we should be able to get it up and running.
Thanks again for all your help and I'll be sure to post my findings when, not if I get it worked out

[Red Warrior]

Thanks so much for your help - I was posting that last night from work and didn't have the radio w/ me and am at work again so don't have it w/ me again haha - Your advice is great and I'm going to hopefully have some time to work through all those in the next couple of days. I'm actually a police officer and our state radio shop guy said that he would call me this week and I could bring it in for him to tune the antenna and then we could work around the other possible grounding issues. Hopefully with his help and your advice we should be able to get it up and running.
Thanks again for all your help and I'll be sure to post my findings when, not if I get it worked out

Honest officer that box on my floor is just for looks. I would really never use it. And those multiple alternators? They keep that bank of batteries charged. My engine can be really hard to start.

[UtahGeneral]

LoL - Yeah yeah, was waitin for the cop jokes to start

[231]

LoL - Yeah yeah, was waitin for the cop jokes to start

LOL. We have quite a few law enforcement officers on the forum. Many aren't that active, but we've had quite a few over the years. No worries.

[UtahGeneral]

Well, took my radio to a buddy at the state radio shop today and we tuned the SWR's on the antenna and still got tons of noise. So he grabbed a magnet mount w/ one of the nice VHF antenna's they use for our public safety radios and plugged it into my radio and then put the antenna on top of his car. Voila, NO MORE NOISE. Sooooo...we started searching for a place on my truck that we could put the antenna and could not find one. We ended up using a truck lid type mount and I put it on the rear corner of the bed of my truck. Turned it on, and again, no noise So now I have a 64" stainless antenna in the roof, and a little bit smaller antenna on the corner of my bed by the tail gate. Haha - Going to take the one in the roof out and put a plug up there. Now I just have to figure out where to run the cable into my cab. Think I'm just gonna drill a hole and put a grommet through the bed and then another hole through the cab behind my seat w/ another grommet and go that route. Cable will be hidden and should be a clean install.

[dragline]

glad you eliminated the noise issue, i know they can be a pain to get rid of. since you have a hole in the roof... it shouldnt hurt that much to drill in behind the seat for a clean install.

let us know what kind of radio that is

[pancake]

dont gues it realy maters now but i had ahorrible noise broblem and mine came from the coax conecters, that doofus from the cb shop didnt fold the sheild back when he put it on i run a little soilder down in the holes and tadahh

[UtahGeneral]

Well I sealed up the hole on my roof today with a cap and some silicone rubber. The radio I'm running is a Pierce/Simpson Tiger 23C. It's an oldie, but seems to work okay. I'd like to get something newer down the road but it will work for now. Also, it has a dial for "mic gain", tone, and one that I can switch from "receive" ( - ), "slide" ( + ), or in the middle of the two ( 0 ). It's also got switches for "rf" or "mono', "anl" or "off" and then to switch from PA to CB.

What the heck is the receive slide and then the rf/mono and anl/off switches????

Thanks guys!!!!!!!!!

[231]

Well I sealed up the hole on my roof today with a cap and some silicone rubber. The radio I'm running is a Pierce/Simpson Tiger 23C. It's an oldie, but seems to work okay. I'd like to get something newer down the road but it will work for now. Also, it has a dial for "mic gain", tone, and one that I can switch from "receive" ( - ), "slide" ( + ), or in the middle of the two ( 0 ). It's also got switches for "rf" or "mono', "anl" or "off" and then to switch from PA to CB.

What the heck is the receive slide and then the rf/mono and anl/off switches????

Thanks guys!!!!!!!!!

The RF/Mono would be like a delta tune, which changes the receive a little bit to compensate for guys who might be slightly off frequency, or help make their audio a little more understandable. It just shifts your receive a little to help your ears that's all. The ANL is "Automatic Noise Limiter" and is an internal noise filter designed to help soften or reduce static and such. I'd probably be running the ANL with the noise problems you've had.

Hope that helps some.

[UtahGeneral]

So, with the RF/Mono - which should I keep that on? Which way does what?

Thanks so much for your help!

[UtahGeneral]

And do you know what the receive vs slide knob is for? Thanks!