Tater Raider wrote:
Now that you pulled the trigger on both, get yourself a Standing Wave Ratio (SWR) meter. This will let you do all the installation and antenna tuning yourself, making the whole thing a break-even or better deal plus you will have a tool to help you troubleshoot problems than can (and likely will) happen down the road.
Tell me more... or info links perhaps
I know nothing of this.
SWR (wikipedia article
for the gory details) is a measure of how much of the power coming out of your radio actually goes out into the antenna, rather than bouncing back toward the radio (ignoring feedline losses). If your antenna is perfectly tuned, then all the power that comes down the coax will be transferred to the antenna and radiated (again, ignoring antenna efficiency). In that case, the standing wave ratio is 1:1.
Life is never perfect, though, so some of the power gets reflected back down the coax and heats up your transmitter instead of doing anything useful. The higher the fraction of power that's reflected, the higher the SWR -- 4% reflected power gives you an SWR of 1.5:1, which is fine. 11% reflection gives an SWR of 2:1, which is generally acceptable. 25% reflection gives 3:1, which can cause overheating in some radios, but can be tolerated by others. Much over that is both risky to the transmitter (overheating can burn out the final amplifier) and detrimental to performance (not much power is getting out into the air). Most CBs aren't too susceptible to thermal damage -- their power output is limited more by laws than by technology, so it's easy and cheap to overbuild the finals.
I'd consider an SWR meter a nice, but not essential, accessory for a CB installation. The antenna's tuning will probably be close enough out of the box to give decent performance. Measuring and adjusting it might get you a few percent improvement, but I've never seen a CB suffer problems from just slapping a magmount antenna on the roof and plugging it in.