CB power

Hi Nathan, Many of the rules for a radio phone installation apply to your Citizen Band radio:

Be very cautious when dealing with any and all info and links provided by Bill Hughes.

You will get all kinds of 'short cut' answers. Run both directly to the battery. Make sure your pos(+) is fused.

tw

Nathan Otis wrote:

Having used Firestik antennas for a number of years, I'd trust anything on their site...even if you provided the link.

Wish you guys'd give it a rest.

-- Old Crow "Yol Bolson!" '82 FLTC-P "Miss Pearl" '95 YJ Rio Grande BS#133, SENS, TOMKAT, MAMBM

Thanks so much, T-Dub. I haven't been around here for quite some time... It's comforting that nothing has changed.

Yup, and fused as close to the battery as convenient. You can either install a circuit breaker or a new fuse block. I don't much care for the inline fuses as the cheaper ones tend to melt under load.

I like these if your go>>

Running from the battery is best.

Use the frame bolt where the battery - attaches. There is usually enough thread on that to put on another bolt.

Grounding in the cab can cause problems for the other electrical systems and noise on your CB. It's better to go to the battery.

Welcome back Nathan. Just use your email filters and you'd be surprised how quiet it is!

tw

Why bother? Attaching at the NEG(-) battery terminal performs the same function as running more lead to the block where the battery grounds. The battery cable is much more than enough to carry the necessary radio ground and saves the further wire run. Just attach both at the battery terminals.

tw

Because Jeeps have had problems in the past with ground loops causing CB noise. It might be worthwhile to consult with a local CB shop it there's one available.

If you are attaching at the battery, how do you get a ground loop?

tw

That should read: Be there or be /squared/.

The short answer is that it must be connected directly on the battery.

But this is not as easy as it seems. CBs - besides the the Power Supply GND wire, may have alternative paths to the Ground, the Antenna Ground and the Chasis of the unit. The shield of the antenna cable is grounded, and this usually connects to the mount of the antenna. Also if the mounting screws of the CB unit are in contact with the chasis of the unit, these too will make a grounding path, if bolted on the car's chasis. You don't want alternative ground paths, as this may greate RF noise in the car's electrical system, which could damage or create interference to the PCM.

A good installation would be to connect the 2 power supply cables (+12V and GND) directry on the battery terminals, with a fuse as close to the battery, and mount the CB unit in a way that there is no connection between it's chasis and the car's chasis. Also the antenna must be mounted on a non-metalic mount, to avoid grounding at the antenna mounting point.

Bill Spiliotopoulos, '96 XJ, '06 TJ.

? "Nathan Otis" ?????? ??? ?????? news:jv6dnUjy-LITHX7bnZ2dnUVZ snipped-for-privacy@comcast.com...

Between the CB and the antenna.

Then your radio or antenna or both are improperly installed. Run both leads directly to the battery.

tw

Not normally possible, read Bill Spiliotopoulos' post in this thread.

BTW, running both leads directly to the battery is also incorrect, proper installation is to isolate the CB from anything metal, isolate the antenna from anything metal, run the antenna ground to the CB and both power and ground from the CB to the battery. This eliminates ground loops but requires some engineering as most antennas will ground through the mount most CB mounts will ground to the body in a typical installation. In almost all cars and trucks this works fine, in Jeeps (at least the older Wagoneers and Cherokees) it seems to create noise, don't know why?

I've never had any problems in any vehicle because I use a portable CB with a magnetic antenna. The antenna grounds only to the CB and the CB is powered by and grounded to the ligher socket. It's worked well so far....

Here's a good link to read

Also the antenna must be mounted on a

This is very bad advice unless the antenna is a "no-ground plane" type Not mounting the base of the antenna to ground will give a very bad SWR. The antenna needs the metal base of the vehicle for the "ground plane"

What'd I'd do is to mount the radio on the metal of the Jeep connect the gnd wire close to the radio, Run a power wire directly to the battery with a inline fuse right at the battery.

Here's a few links

I agree. I posted this late at night and wasn't clearly thinking.

After some more thought, I have to say that the antenna mount must be grounded to the car body, so the RF circuit closes through the antenna cable ground. Otherwise the antenna cable becomes an antenna itself, changing the RF output impedance and increased SWR.

I would also ground the CB unit with the GND power supply wire on the battery terminal. I wouldn't ground the CB chassis though, as this would create an alternative RF path bypassing the antenna cable ground and increasing SWR again. An RF filter may be required on both power supply wires, if not already included inside the CB unit, to prevent an RF loop through the power supply wires.

Sorry for the confusion.

Bill Spiliotopoulos, '96 XJ, '06 TJ.

I ran a Radio Shack in my younger days and I have to agree with this. I always used a fused lighter socket plug so I could pull the unit at night. Sold a bunch to customers and never had a problem or complaint. For antennas I used both a center loaded magnet mount and a 108" stainless steel whip. Of course the whip gave better results, but again the magnet mount could be pulled at night. One caution with magnet mounts, make sure they're clean and dust free when you put them on. If the bottom of the magnet mount or vehicle surface is dirty it could mark the finish of the vehicle.