Cb shop Kansas City kansas

Try these guys. I haven't been there in years. Call first.
Kollman Radio
(913) 229-6764
https://maps.app.goo.gl/ajvUqqXZLet44gD17

 

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The whip on trucker 2000 type antennas I have seen are usually a good bit too long and its scary trimming as much off as it might need when you just spent 80 bucks on it.

The last Trucker 3500 whip I saw I think 5 inches of it had to be cut off to get the lowest SWR in the end.
It was set first with a 6 ft coax that I brought with me and my antenna analyzer. Then we got lowest SWR's and hooked it up to his radio and 18 ft coax the SWR's were high again. So we had to cut another inch off to get low SWR again. you know like 1.5 on ch1 1.3 on ch 20 and 1.3 on ch 40

If you have a stainless steel whip normally way too long and ch1 is lower than ch 40 on the SWR meter it needs cutting off little at a time and rechecking.
A pro might take an inch off at a time because he understands whats going on with the SWR meter and how far off the antenna is from the correct length. And maybe he's sold hundreds of them.

If the antenna has an adjustable screw on it and ch 1 is lower than 40 on the SWR meter you lower the screw and check it again because the antenna is too long.



Another issue to consider is if you had a milldly shorted antenna the SWR would stay high no matter where you adjust the antenna. If the antenna was 100% shorted center pin to outer shield the SWR will be off the scale high.

So its important to make sure the antenna is not grounding out in any way before taking SWR measurements and whacking off inches of a new antenna. Easy to do with a continuity test from center pin to outer jacket of the plug.

Its hard to grasp with a regular SWR meter but there is a V curve with the lowest SWR for the band being right in the center of the V.
When you take readings on channel 1 and 40 to see which is lower and which is highest you are trying to figure out which side of the V the antenna is falling on at its current length.

11 Meter is a fairly narrow band and for instance if you cut the antenna too short it may not work at all on 11 meter but would work on 10 meter now.

The length of the antenna determines if it will work in the desired band.
I have drawn a paint pic to help illustrate what folks see easily with antenna analyzers that give live update without constantly rechecking SWR.

its better to learn how to do it yourself man. If You pay someone to do it today then some clown steals your antenna tomorrow or you break it off on a limb you didn't see coming and there you're back to looking for the SWR Pro man in another town.


Here is a video that shows the SWR curve I believe on the 70 centimeter ham band.
If you stick with him a minute you'll see the yellow line on his analyzer come into view as he starts off much too short. As he lengthens the antenna you'll finally see the yellow V come into view and hit the sweet spot right in the center of the V.
This is the 450 MHZ ham band or 70 centimeter band which uses a very tiny antenna because of its higher frequency but the principle is exactly the same.

 

First things first. If all you have is an SWR meter, you are not in a position to do this without risking damaging your antenna. You need to know if your antenna is resonant at any frequency first before you do anything. If you are unable to do this you need to find someone that has the proper test equipment. If you wrongly assume the antenna needs to be trimmed, you may end up needing to purchase another antenna or another whip which can cost as much as your antenna.