SWR TESTING

[RookieRooster]

Hello, i just got my CB tuned and peaked and its kicking out 40 watts now. My SWR reader, which can test either 10 watt or 100 watt radios is set to ten watts. My SWRs have been kind of high and channel 40 is significantly higher than channel 1, meaning antenna is to high. Without doing anything after taking my truck to the CB shop which I have left with a SWR of 1.5, my SWRs went up. My antenna is set all the way down, its a 2 foot firestick. Could my SWR readings be false due to the SWR reader?

 

[RookieRooster]

I wanted to put my 100 watt amplifier after I resolved my SWR issues.

 

[mmckenna]

40 watt radio/100 watt amp into a 2 foot tall antenna sounds like you have your priorities in the wrong order.
The most important part of your radio system isn't the amplifier, it's your antenna. If you want the system to work correctly, and make use of all that 40 watts or 100 watts, you really need to get a decent antenna. Trying to cram 108" of antenna into 24 inches is going to result in a very inefficient setup.

So, before you go too far with this, consider getting a bigger antenna.

Also, make sure your 100 watt amp will tolerate being driven with 40 watts...

You need to make sure your SWR meter is calibrated. If your radio puts out 40 watts, you should have your SWR meter set at the 100 watt setting. Without knowing what SWR meter you are using, it would be difficult for anyone to give you guidance on how to do this.

Also, where you are when you test the SWR matters. If you are parked near large metal objects (house, barn, garage door, lamp post, etc) it'll throw things off.

 

[alcahuete]

Also, if you are running 40w, 100w amp is a complete waste of money. The difference on the receive end will not even be 1 S-unit. It will be slightly more than half an S-unit, to be more precise.

As was said, get a better antenna before you waste your money on an amp.

 

[RookieRooster]

40 watt radio/100 watt amp into a 2 foot tall antenna sounds like you have your priorities in the wrong order.
The most important part of your radio system isn't the amplifier, it's your antenna. If you want the system to work correctly, and make use of all that 40 watts or 100 watts, you really need to get a decent antenna. Trying to cram 108" of antenna into 24 inches is going to result in a very inefficient setup.

So, before you go too far with this, consider getting a bigger antenna.

Also, make sure your 100 watt amp will tolerate being driven with 40 watts...

You need to make sure your SWR meter is calibrated. If your radio puts out 40 watts, you should have your SWR meter set at the 100 watt setting. Without knowing what SWR meter you are using, it would be difficult for anyone to give you guidance on how to do this.

Also, where you are when you test the SWR matters. If you are parked near large metal objects (house, barn, garage door, lamp post, etc) it'll throw things off.

The fwo foot antenna was just temporary.

 

[KANE4109]

I don't think you will ever get the 2 ft antenna to behave right with that radio. I would go ahead and spring for a better antenna.

 

[mmckenna]

The fwo foot antenna was just temporary.

OK, good deal.
I wouldn't spend a lot of time trying to tune an antenna like that. Get the right antenna installed and put your effort into that.

 

[slowmover]

What brand & model of semi truck? Only a tiny number are easy to get good performance (relative to other trucks).

IMO, you should always shoot for 14’ clearance (13’5” shortest) with the LONGEST antenna you can fit (not less than 4.5’).

As to amps making no difference in a big truck, that’s not in the least accurate. Power is the crutch necessary more often than not as big truck antenna mounts make for very poor ground plane.

50-150W gets the job done. A car or pickup where best practice is followed (admittedly rare) doesn’t need the wattage to produce results consistent with the expected 3-5/miles.

OP, an amp won’t solve THE OTHER PROBLEM. Being able hear as far as others hear you. For which you’ll want DSP audio filtration.

CBs and Exports don’t have it. A stand alone or external speaker integrated unit is how to get that. Your radio and antenna system can already receive better than you realize, but clearing up the noise is what’s necessary.

Hear, and Get Heard.

FWIW I often reply to drivers asking questions who can’t hear me. There’s no reason they can’t hear me but one (where all else is the same).

.

 

[slowmover]

View attachment 104842

I don't think you will ever get the 2 ft antenna to behave right with that radio. I would go ahead and spring for a better antenna.

Perfect!!

 

[slowmover]

Went back on OPs posts and “truck” apparently means pickup.

A dual final 40W radio is adequate to GET OUT. As was noted, it’s all about the antenna (location & mount). DSP is still desirable.