Last week a friend and I put a CB in my truck. A small Maxon. It's nothing great. We went to the truck stop and bought Wilson 3 ft antennas and mirror mounts. I don't get reception for Crap!! About 1-2 miles on a clear day!! What's up with this? I see that I can tune the tips of the antenna by moving them up or down. But neither of us know how to do this.

Also since mounting the antennas and coax I get a fierce whistle/roar in the cab when winding up the turbo. I can't tell if it's coming from where the coax is squeezed between the door and fender or if my turbo is coming apart. It's real annoying.

Please help before I get upset and rip the darn thing out!

Thanks

Edited by administrator

 

Go here Firestik Technical Documents and read up.

Chock full of all kinds of CB and antenna information.

A lot easier to point you there than try to explain SWR and such.


phox

 

First things first , Get your self a cheap SWR Meter and a coax jumper. Make sure your coax isnt pinched or cut anywhere. SWR (Standing Wave Ratio) Needs to be below 1.5 . You can get a meter at radio shack. if the swrs are high, or just jump all the way up it indicates a short in your coax, a bad ground, or reflection! It is very important to check swrs, DO NOT KEY THE RADIO If THE SWR's ARE ABOVE 1.7. It will burn the radio up. The sound you hear when the engine starts to pickup is a bad ground on the radio, i would recomend you ground to the block!

If you need some help PM or email me!

 

also make sure the antennae base is grounded. if u mounted them on the mirrors check to make sure the mirrors arn't insulated from doors. better off mounting them in the stake pockets behind cab.
using two antennae's on a pickup isn't the best scenario, also u have to meter each one separetly. make sure your radio is not mounted close to the vehicle's computor's

 

The above is all excellent advice! Usually it is a bad ground. I'll go along with the mirror (s) being isolated from the truck. Not a bad idea to use silicone grease at alll the connections as well.

Yes to the bad ground on the block as well. Go through ALL your ground wires in the engine compartment, remove, clean, dielectric (silicone) grease and reinstall. It's amazing what a wire brush, and a little time will do. Also check the grounding of your radio (great advice), even add a ground wire.

One other note, I just took my regular car antenna apart. Removed the mast, then the mounting base on the fender, (reception was poor, altenator whine was noticeable on weaker stations), cleaned the area on the inside of the fender that the base mounts to (and makes a ground to) then silicone greased it. You will see a clip on the base (remember it is on the underside of the fender-but can be reached from the outside of the truck), that has a couple little teeth in it designed to bite into the metal fender to form a ground, this was getting grungy, so that got cleaned (wire brush) and greased as well. The whole thing got reassembled and the reception has never been so good. Whine is gone as well. Hopefully the grease will protect it.

Matching your antennas will help (swr), but you should be getting better reception than what you are getting. Kevin

 

Best thing to do to remove errant noise is to wire the CB directly to the battery, power and ground.
Learned that one from Firestik.

Any circuit you use to power the CB will have some noise inducing component in it that the CB will amplify.

Luckily, we don't have to worry about spark plug noise like the gassers do.


phox

 

A well grounded antenna, and a low VSWR go hand-in-hand. You can't get a good match unless the antenna is well grounded. The "stick" portion of the antenna is only half of the antenna In this case, the body of the truck represents the other half. I haven't looked at a schematic of a CB in years, but modern amateur tranceivers have a hight SWR protection circuit in them. As the SWR begins to rise past 2.5:1, the radio reduces the output power to protect itself. CB may now do the same thing. So if you have a poor match, your radio may not be transmitting at all. I have my antennas mounted alongside the hood using a firestik cowl bracket made for 2nd generation Rams. It's stainless steel and makes an excellent connection to the trucks body. Using a frequency just above the CB band, and a 5 watts, I've talked all over the US, Europe, the Carribean, and South America.