Tuning a CB???

[Sitting Bull]

I've heard people warning me about this, but I'm not really sure what they mean. What is there to tune on a CB? Is it just the knobs on the outside, and your tuning it according to your antenna??? I'm completely in the dark here...

[JeepFreak]

Tuning is done with a SWR meter. I think Radio Shack still has them. Here is a link to tuning you system.

http://www.everhardtantennas.com/tuning.htm

[FSJ Thing]

Well, what I do, is I hook up my in-line SWR meter, turn on my CB, and then notice it has a built in SWR meter. Then I wonder what the heck an SWR meter does, and what exacty I'm supposed to "adjust". Next, I start twisting the antenna around on it's base and usually bend a brand new steel whip in the process. Then I cuss a bunch and start playing with the mike, usually repeating things I've heard the dukes of hazzard say. As soon as someone answers back, or I get somekind of feed back that might be someone trying to communicate with me, I call it good and tell everyone that I got it dialed in "just right". :D

[Kimbrough]

Go to www.firestik.com (http://www.firestik.com)
Excellent info on their site. Typically, their antennas come tuned. They recommend using a meter but when I hooked one up to my cb (with a Firestik) it was perfect.

[Rande]

There are two meanings. Tuning a CB sometimes refers to having the transmitter tuned for maximum power. I suggest you don't have this done. Some shops really push this as they make good money from it. The small amount of extra power you normally gain from this procedure is not worth the money and it stresses the transmitter circuitry beyond its design. Just have the shop set the power to the proper levels and make sure its on frequency. Don't let them "peak" it.

The other meaning is refering to the antenna system. A transmitting antenna's length is related to the frequency it is transmitting at. Antennas come from the manufacturer set to a certain length but they have no idea what sort of vehicle you will be mounting it on. What sort of vehicle and where on the vehicle and how it is mounted will all affect the tuning. You will need an SWR meter and a short jumper of coax cable to connect the meter to the radio. The meter goes between the radio and the antenna. A measurement is taken and the antenna tuned accordingly. Sometimes the antenna whip may have to lengthened or perhaps shortened (most often its shortened). This antenna tuning is VERY important. If the match between the radio and the antenna is far enough off, it can damage the output transisters of the transmit section and then its off to the repair shop for new transisters.

Another common mod is to clip the AMC (automatic modulation control). In the old days, you could overdrive the audio section of the transmitter by using an amplified microphone (power mic) and get a few more watts of output. When the 40 channel radios came out, the FCC demanded some additional control over the audio circuits. Overdriving the mic audio amplifier caused a lot of distortion to be transmitted with the audio signal and this caused a lot of interference on adjacent channels. The AMC mod will disable this audio control and allow the audio to be overdriven. Its not worth the interference to gain a few watts of power. A power mic can still be useful in a base station (even with AMC circuits) but for a vehicle its not very good. It will amplify your voice but it will also amplify all the noise in your truck and make you very hard to understand in the receiving radio. Don't let someone talk you into a power mic for a radio going into a truck.

[ December 03, 2003, 07:05 PM: Message edited by: Rande ]

[firechero]

dang and i thought i could just hook up the uniden bearcat and go, course all the talk i hear is staticky

[Rande]

Nope, sorry, just not that easy. Be SURE you get that antenna tuned or you may wind up wrecking that new radio. Any CB shop will check the antenna for a nominal fee.

I always recommend buying the radio and antenna from a CB shop. It costs a bit more than the local wallyworld but when you get everything installed, they will usually check and adjust the antenna for free or perhaps for a small fee. Its usually a good idea to form something of a relationship with the local CB shop.

If there's a problem, its better to spend a few bucks fixing that than having to buy a new radio and then spend the money having the antenna fixed.

I was in a CB shop in Tampa when a fellow buying a new CB refused the Tech's offer to install the radio and antenna for a fee. The guy and his buddy went out in the parking lot and installed it themselves. After doing some work on my radio, thwe tech and I stood there talking for a while and the guy comes back in saying the radio didn't work. The tech took the radio, checked it out and found the cheapskate didn't know what he was doing and he hooked the power cord up backwards and blew his brand new radio. Was very mad when the shop wouldn't give a new radio for free. A few dollars spent for a pro, are almost always worth it.