HELP PLEASE - My SWR is "WAY TOO HIGH"

Any ideas on how to fix it in an 08 Freightliner Cascadia with stock antennas? I'm getting a 3.1 - 3.3 on every 1, 20, and 40. There isn't any place to put another antenna and I have no idea how to check the grounding on the stock stuff. Raising the antenna more than a couple of inches will have it towering over our trailer and running the risk of hitting stuff. I'm bum out of ideas.

 

What happens when you lengthen or shorten the whips? If they are "firestick" style, you CAN carefully remove the cover from the tips. Check to see where your lowest SWR is (or if it changes as you flip thru the channels) IF it is HIGHER on channel 1 than it is on 40, then the antenna is too SHORT. IF SWR is HIGHER on 40 than it is on CH1, then it is too LONG. Set the radio to channel 20 (or 19 since that's where you will likely spend a lot of time), then carefully "pick" out the wire from inside the top of the fiberglass whip. Trim off about a 1/4" each (patience is the name of the game lest you trim off TOO much ) That is, of course, assuming the antenna is too long to start with! IF that doesn't change anything S T O P!!!!!!!!!! Something ELSE is wrong! IF it works, a drop of crazy glue on the wire at the top will secure things back in place, and you can replace the top cover.


Gadfly

 

I'm probably going to buy dual firesticks or similar and see how that works. I've used fiberglass before and that sucked! That and I figure on a company truck I can transfer antenna's to another easily.Thanks for the info Gadfly.

 

Try using a set of booster cables and ground the antenna bracket to a solid metal piece on the frame. Painted surfaces will not work as a ground. Maybe the 5th wheel or engine. If the SWR drops, you will at least know that you still have a grounding problem.
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These trucks are notorious for poor grounding. At least you will know for sure whether you have everything satisfactorally grounded.
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Is it possible for you to swap your CB radio into another truck and then check the SWR reading in that truck?

 

there is indeed no way for me to throw it into another truck. I did, however, recently transfer this radio from a Volvo that I had the antenna tuned for to this.. and in the volvo it wasn't the lowest but it was at least in a tolerable range. The tech told me there was indeed a problem with the grounding on the volvo.. so I have no doubt then there is a grounding issue on this truck.

When we get home later this weekend I will throw the jumper cable on it and see if it works and post the results. Not quite sure, however, how I would fix the ground on the stock antennas.. and as I said there is no possibility of installing any other antennas with how these mirrors are designed. Shes a great truck but they design them so drivers can't mod much anymore!

 

The following is from a book called "The Big Dummy's Guide To C.B. Radio" page 47:
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"IF the [SWR] meter reads less than 1.5, your antenna is working properly. If it reads more than 2, your antenna probably needs adjustment. If it reads more than 3, check all connections at the antenna for possible bad connections; or the antenna or the center wire of the coax might be touching the body of the vehicle."
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It is unfortunate that the only group that uses CB radios now is a few truck drivers. With so little demand, there are just so few decent books on CB radio around. The very few books that do exist are really old.

 

It sounds like Your trying to use antennas that need a "ground plane" in a "no ground plane" mount. You need to use no ground plane antennas with those. 3 different types of antenna out there for vehicles. Fiberglass whip, center coil (example: Wilson 2000 trucker) and no ground plane which do not require a ground to work. I had to learn the hard way when a CB shop made fun of the rookie

 

Below is a link to how I solved the Cascadia problem. Check page 3 and 4, with pictures. I don't remember what the 08 looked like. If the bracket I have will work for you, I'll send it to you for whatever the shipping cost is. Here is the link. Cascadia Antenna Solutions

 

Rf bonding is the closest to "grounding" as you see it....
Booster cables to the chassie can and likely will change things but not in a good way...All that does is add length to said antenna...So best go read some threads on here already..
Watch this for a better idea..