New Driver needs advice on CB and antennas

Well, there are people on both sides of the coax length issue. Some say it should be inn 1/4 increments of the wavelength, and others say it doesn't matter. So.....In my way of thinking, I cover both bases by keeping the coax in 9 foot lengths. The one camp will say it is the right length, while the other camp will say that the length is ok, since it does not matter either way. One thing I did forget to say, which both camps can agree on, is the cable should be as short as it can be between the radio and antenna. If a 9 foot cable will not quite reach, I would rather move the radio a little, than add another 9 feet of cable.

Another thing I forgot to hit on, is the fact that twin antennas are a waste of money, unless they are properly co-phased, and at least 9 feet away from each other. Anyone who tells you different, is just trying to sell you 2 antennas, when 1 will do.

 

I've heard this several time. The problem come in because 9' is NOT the correct length for a 1/4 wavelength for 27 mhz. As an example for Channel 19 (27.185 MHz) a 1/4 wavelength would be 5.676 feet for RG-8.

Take a look at http://signalengineering.com/ultimate/coax_basics.html It presents a pretty good discussion on coax basics.

One of a major antenna manufacturers claims the coax must be 18 foot. Take a look at http://www.firestik.com/Tech_Docs/coaxtalk.htm

As far as co-phasing on a big rig getting a spacing is not that hard. Most mirror mount will pretty close to 9 foot. However, the only reason to use twin antennas is the effect of the trailer blocking the signal. In addition a co-phased system will direct the signal up and down the highway.

Leon
(kc0iv)