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Originally Posted by BigDaddyD
What should I look for in an antenna? Are different antennas better for different trucks because of what the truck is made out of? What about antennas for Cell phone signal boosting will they interfere with the CB antenna? Finally does anyone know if there are there any good CB shops in WA/ID that can set up my antenna/radio?
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A good CB antenna has a wide "Q" or bandwidth, is screwdriver tunable, where either you lengthen or shorten the antenna whip with a set screw like in a Wilson or a Monkey Made, or there is a screw at the top of the antenna that you can turn like in a Firestik. The full size 108" whip is not possible in a big truck, so most antennas have loading coils. A 4 or 5 foot 5/8 wavelength antenna is usually what you'll find on a truck. There are some 1/4 antennas as well.
An antenna should not bow too much when the truck is moving through the wind. This is where fibreglass antennas are preferable. It must also take a lot of abuse, such as hitting tree sapplings on the passenger side, and that's why you see some whips have the bend at the top.
In an antenna system you want to get the Standing Wave Ratio [SWR] as low as possible, which is the ratio of forward power and reflected power back into the radio. Anything greater than 3:1 on the SWR meter means that the antenna is not hooked up correctly, or there is insufficient counterpoise (ground). Generally, you want to see anywhere between 1.2:1 to 1.5:1 from one side of the CB band to the other. In the middle of the band, Ch 19, it'll be closer to 1:1.
If you run two antennas, the coax harness must be RG-59 rated at 75 ohms. A single antenna requires RG-58 50 ohms. The actual impedence of the antenna is generally lower, somewhere around 25 ohms, however, the radio output is rated for 50 ohms. A trick for this is to take your excess coax and coil it tight, to create a passive inductor in the coaxial system, and can change the impedence of the wire a little bit closer to the antenna's. Running 2 antennas generally complements the odd position the antenna is. Ideally, we'd be putting our antenna on top of the trailer. Haha, if only all bridges were 20 feet in clearance. When you have an antenna offset from its counterpoise, the body of the truck, the radiation pattern becomes oblong towards the direction of the body, so adding a second antenna on the other side smoothens out the irregular radiation pattern closer to a circle. Even still, we end up with a big lobe going backwards in relation to our truck, and a slightly smaller lobe going forwards, coincidentally in both directions of the highway.
The type of truck you use does not change what type of antenna you should use. However, regardless of personal style preferences, some folks angle their antennas forward, one, because their antennas a little too long and would otherwise be overheight (mine), to counteract the bowing in the wind, and also to polarize their antennas a little closer to horizontal. Does it make much difference? Not really. The more metal in the body, the more counterpoise, and the better your Rx and Tx.
The CB band is in the middle of the old 11 meter band (27Mhz), and the cell phone band is near 37 centimeters (800 Mhz). They are worlds apart, and will not interfere with one another.
My rig is a Galaxy 979 co-harnessed to 2 Wilson 5000's w/ 67" whips. On quiet days, I'll reach well past the 20 mile radius. On some days, why I'd want to hear that far I'm not sure..... :?
And sorry, I dont know of any shops in WA or ID.
Anyways, hopes this helps a little.
CB Antennas???
