I posted a while back about ALOT of interferance from my alternator on my CB. Still haven't really fixed it because I refuse to spend $100 on a pair of "high resistance" wires to solve the problem. So my new trick I read about on ham forums is to put a cap inline on the power cord. I did this and it helped, but it didn't help too, kinda wierd. But anyways, I was thinking about this when I went to start my truck this morning. The CB is wired directly to the battery so it has power even when the trucks off (no I don't leave it on [:'(]) but I was wondering if the cap is gonna slowly drain my battery being connected between the + and - on the battery. The cap is 47 uf by the way. Its been a while since I took electronics.

 

Nobody remembers this kinda electrical stuff?!

 

No a cap will not drain the battery. Consider it a battery it's self.
Once it's charged, it will stay charged till something draws power from it.

Never heard of putting a cap on a C.B., new to me. See a cap is used in car sterio power wire because of the large demand of power when the amp requires the extra power during hard hit's of bass.
Does it cause any problems during transmit? I can't see a cap removeing any engine noise.

I would go over all my engine grounds. Sand the paint off there the straps go to the body where they will make a good contact, larger ground wire from the battery to the body and run the radio ground as short as possible "ground it near the radio and cut off the rest. I hooked mine up as if I was hooking up an amp, try to keep the ground as short as possible and make sure it's grounded good.

Most noise can come from a bad ground somewhere but wires can also cause noises, the only noise I get in my truck on my radio is from the blinker for some reason. I barely get any increase in noise when I crank the truck, maybe 1db increase from running and off.

I ran a 8 gauge wire to the battery to my radio, well it's in my power distrubution box under the hood but it's directly to the battery wire post. My radio ground wire is the radio's wire but it's no more than a foot long. I haven't played with any of my grounds yet and it seems good. I have factory plug wires, brass dist. cap and rotor button and nothing special to keep noise down.
It may be the filtering in the radio but noise isn't a problem on mine.

I have a Ranger RCI-6900F150 and a wilson 5000 Mag mount on my ram.

 

If the noise is comeing from the engine, I would go over all the grounds and make sure they are grounded well. Scrap off any paint where they go on the body and do the rest I mentioned.

Engine has to be grounded to the battery and ground from the engine to the body, then ground from the battery to the body. I'm going to bet it's a ground problem as I said. Don't run the c.b.'s ground to the battery, run it to the body near the radio.

 

are you sure its coming from your alterantor? could be your ignition system (coil, Spark plug wires, dist cap) I was getting a lot of intererance and found that i had a cracked wire to my alt, wrapped it with electrical tape for a temprary fix. didnt solve the noise though so i looked further and my coil was splitting and my coil wire and two spark plug wires were cracked. I replaced the coil, wires and dist cap and the noise is gone

 

i've been fooling around with cb's in my 01. the first try was to use a handheld with a cig lighter plug for power. there was a lot of electrical interference coming through. the cb static acted like a tach, speeding up with engine speed. next i got a cobra 29 nw and used the cig lighter plug. it also had a lot of electrical noise. i finally wired it in, pulling a fused wire from the parking light fuse on the end of the dash, grounded to base of steering column, and put in a Pyramid Brand noise filter. It worked great, taking out all the electrical noise. I don't know if its a capacitor or not. It was about $5. By the way, I mounted it in a deep 10 inch bracket, vertical, in the floorboard in front of the middle seat. edit.. i mounted a 2ft firestick antenna at the front of the bed, drivers side, w/ 3in spring, homemade bracket. it clears the garage door opener with about 2in to spare.

Pyramid NS10 10 Amp In-Line Noise Suppressor $4.95
# Easily Installed
# 10 Amps
# Reduces and Eliminates Engine Interference
# Compatible w/Receivers, Equalizers & Amplifiers

Kalibur BB29 7 1/8 Inch Bubba Bracket $16.99
Oversized mounting bracket designed to mount the radio facing straight up. Clearance at the bottom for the PL259 antenna connector and power cord. Ideal for mounting radio on the hump.. Fits Cobra 29's and Uniden PC76/78 and larger Midland radios.


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Putting a capacitor across the input power lines of an electrical device is a standard noise reduction technique called "bypassing", it reduces the noise on the power lines. The capacitor should be installed across the CB input power terminals, not across the +12V input terminal and a chassis ground even a few inches away or across the terminals of the battery. Connect the cap right across the +12V input and the ground wire input of the CB. As Magnum318 said, there is no risk of draining your battery. If your 47uF cap isn't working, try something smaller. If you need a few caps to try, let me know and I'll drop a few in the mail to you. Unless you know what frequencies you're trying to filter out, I can't do the math to determine what size cap to use.

Another thing you can try is to twist the (+) and (-) wires coming from your power supply (battery) to your CB. By having both wires almost exactly the same length and in almost exactly the same location, they will pick up almost exactly the same noise and their voltage difference at any/every point in time will be closer to a constant value. Noise spikes have less of an effect if they are on both the (+) and ground lines of a power supply. An easy way to twist wires quickly is to secure both wires on one end and put the other end of the two wires in an electric drill, go slowly and keep some tension on the wires for a nice even twist.

 

While were on this topic, I was wondering how all you guys mounted you cb's. Got any pics? Right now mine is mounted straight up like the one in the picture. I have a glaxy radio dx 95 i believe (big radio) and I don't like it where it is mounted.

 

Mine is mounted directly to the dash, I have a 94 auto 2wd so I have alot of room to play. Rig looks nice in my truck, face is almost the same grey as the dash. I haven't got a pic yet but will later, not tonight.

I'm interested to see where everyone mounts their antenna at, mine is on the roof of the cab but I think it looks bad. Wilson 5000 mag mont on top the cab [:'(] Like to see some other mounts, gonna make a new post......

 

Antenna mounts