CB SWR Help

millerjl

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Hey guys, have read through the threads and still need a little help. Got my Cooltech package installed and finally got to check my SWR. Finding a good spot to do this is a pain but its now done.

1st readings:
Channel 1: just over 3
channel 40: just above 0

Read that my antennae is too short, so I adjusted it.

2nd readings:
channel 1: 1.9
channel 40: 1.9

That is the best I can get it on both channels, I played with the tuning a lot to get it right in the middle. Using a 3ft firestick with the cooltech mount on the upper hinge.

Should I be checking grounds? or is that the best I can get with the 3ft?

The antennae, is dead center in the mount and installed correctly. The cable is run behind all the panels with no coils or anything in it. The only thing I am iffy on is the CB ground behind the kick panel. I connected it to the second bolt, not the one at the bottom as in some of the threads. Trying to narrow it down before I pull that damn panel off again. May just run a ground to the battery. Am I missing anything obvious?

Appreciate any and all input...

 

prerunner1982

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What is the SWR on channel 20?
SWR is a curve, like a U it is high at the ends and low in the middle.
The shorter the antenna the more quickly the SWR rises at each end. This is because shorter antennas are more narrow-banded, the range of frequencies they can operate on is smaller.
A 108" whip in comparison is much more broad-banded and will have a relatively flat SWR across all 40 channels.

This is likely the best you will get from a 3' antenna, even if you hadn't mentioned what length antenna you were using I would have guessed a 2-3' based on the SWR characteristics.
 

Fuel Fire Desire

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I have had a 4’ firestick and am currently running a 3’ firedtick in the factory am/fm antenna location. IIRC Ch. 1 is 1.5, Ch. 40 is 1.6, and Ch. 19 is 1:1 with either installed.

1.9 on either end sounds about right, especially if you have it next to your spare. Can you do better? Yeah probably......but do you need to? No.
 

tCub

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Those numbers sound pretty good but you can double check your install.

When I set up the CoolTech bracket, I made a boo-boo and had terrible SWR numbers. Took it apart and back together properly and I was able actually start tuning.

I would find more than one location to test and tune in too. I know it’s tough though - at least where I’m at.

Lastly, consider adding a spring not only for more flexibility off road (really comes in handy) but also to push the antenna slightly higher.
 
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millerjl

millerjl

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I will go through everything one last time... it is a 3ft, so it only clears I think 9 inches above the top. I did pick up some CB chatter on the freeway on the way home so it is working. Was initially going to do a spring but then it wouldn't clear my parking garage at work and I don't want to have to take it off with a quick disco.
 


Fuel Fire Desire

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I will go through everything one last time... it is a 3ft, so it only clears I think 9 inches above the top. I did pick up some CB chatter on the freeway on the way home so it is working. Was initially going to do a spring but then it wouldn't clear my parking garage at work and I don't want to have to take it off with a quick disco.

SWR has nothing to do with reception and everything to do with efficiency of transmission. You could have an abysmal SWR, but still hear just fine. Don’t let what you hear make you believe you’re OK.

That said....1.9 is just fine, and well below the ‘danger zone’ of 3+. I’d just leave it as is. You’re fine.
 
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millerjl

millerjl

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SWR has nothing to do with reception and everything to do with efficiency of transmission. You could have an abysmal SWR, but still hear just fine. Don’t let what you hear make you believe you’re OK.

That said....1.9 is just fine, and well below the ‘danger zone’ of 3+. I’d just leave it as is. You’re fine.
Understood on the SWR having nothing to do with transmission. Was just meaning that it was hooked up and had power and I was hearing stuff so at least that piece seemed to be working. ;)

Went through and tightened everything up, including the set screw on the antennae and now have the following.

Channel 1: 1.8
Channel 20: just above 0
Channel 40: 1.6

Think I am good, going to leave it alone now.

Thanks for the advice everyone.
 

Hgrace

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Understood on the SWR having nothing to do with transmission. Was just meaning that it was hooked up and had power and I was hearing stuff so at least that piece seemed to be working. ;)

Went through and tightened everything up, including the set screw on the antennae and now have the following.

Channel 1: 1.8
Channel 20: just above 0
Channel 40: 1.6

Think I am good, going to leave it alone now.

Thanks for the advice everyone.
Won't get much better than that. Good job.

 

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