Since most people optimize using channels 1 and 40, I was wondering what channels "outside the range" people were using.

Are many people adjusting the SWR over a more narrow band for CB?

 

First of all, Dave, good find.

Ive always set the SWR for the best at channel 20 and checked 1 and 40 as a reference.
I feel as long as the middle is near to 1.5, the rest cant be that far off.
Worst Iv had doing this is a 1.9 on 40 and 1.7 on 1.
MAybe m missing something.

 

What he meant by that was that many antennas aren't broad banded enough to provide desirable SWR throughout the 40 channels.

But believe it or not a modded CBs can be made to tx 40 channels above, and 40 channels below the normal channels. There is a whole world of people using them. They call it the "free band". I was a "free bander" or "bandit" operator once myself.

And yes donnie....Even in the ham bands I usually always try and check swr in the middle of the band/s.

Edit: Oh....I forgot to say that those "free band" freqs are indeed illegal in the US, but not all around the world.

 

Now that I think about it, although I emailed them about what he said about changing your swr from the radio, even what he said about having an external swr meter is wrong too. That's EXACTLY what an swr meter allows you to do.....optimise your swr for the frequencies you operate on. This guy is all screwed up....

 

Come on now don't hold back tell us what you really think!

 

I agree that adjusting SWR and calibrating a meter to read the correct SWR are very different. I also read the article that you are referring. However, I didn’t catch that.

73
N5LO

 

dam, now i'm going to have to google what the heck a SWR is. i had a cb for hearing the big trucks tell me where the smokies were and traffic etc. now i want a cb and apparently there is a whole new bunch of stuff i gotta learn lol.

 

Nothing has really changed except the radios. The Physics stays the same. ...

SWR stands for "standing wave ratio". What this means is, in layman's terms:

An antenna needs to radiate RF power output from the radio to be able to properly transmit (and receive) at a given frequency. Think of it this way.....

Take a garden hose (the antenna) that is not kinked at all. The water (RF energy) flows freely through it. If there is a kink, or obstruction (antenna not properly tuned) the water will back up and not flow out the end of the hose as well.

What happens when the antenna isn't tuned (matched) to the frequency, a portion of the RF (radio frequency) power will be reflected back along the coax towards the radio. If the swr isn't that bad, meaning the antenna is fairly tuned, the amount of RF that is reflected will dissipate as only a little bit of heat and most of the RF power will be transmitted. But if the swr is pretty bad then the RF can be reflected back into the radio enough to cause damage.

Ideally what we strive for is for ALL the RF power to radiate out of the antenna ie....a perfect match, or a 1.1:1 swr ratio. Which for the most part is almost unattainable because of a variety of different factors we won't go into now. But by tuning the antenna (lengthening or shortening), we try to get as close as possible to the lowest SWR we can achieve over the given amout of frequencies we will be using. In this case the 40 CB channels. Remember high swr means loss of RF power radiating from the antenna. And when you are only allowed 4 watts output from the CB to start with, well, as you would imagine, every little bit helps.

If you want to read technical data on SWR go here. http://en.wikipedia.org/wiki/Standing_wave_ratio Most will not make sense but scroll down and read where it says "Practical implications of SWR." This will give you a better idea of what it's all about.