cobra 29

gee channel jumper, that was real helpful for him, NOT. have a CB shop come out to the truck for $10 and run an SWR check with recommendations. I've been running my 1994 '29 for 3 years in a Volvo with the lite coming on. the calibration isn't that far off.

 

Here's a few tips...when you test your SWR, do not have the truck parked next to any metal light poles/other trucks and don't have it parked next to buildings. If at all possible, find an open parking lot away from everything and test.

The SWR test is simply determining how much of the signal is actually going out instead of being sent back down to the radio which in turn ends up as heat, thus damaging the finals. Things such as metal poles reflect the power back down into the antenna. That's what causes issues and hinders your range.

When you do your SWR test, your best bet is to invest in an external SWR meter. (they're better/more accurate than the built in ones in the radio) I like the ones Radio Shack sells for $38. It's p/n 21-534. Make sure your power is down to 10 watts. You want the SWR to be as close to 1.1:1 as possible....1.5:1 is good, 2.1:1 is satisfactory, 3.1:1 and up is bad.

Now when you go to do the SWR checks, what I like to do is test the radio on channel 1, then channel 20, then channel 40. If your SWR is higher on 1 than 40, your antenna is too long. And if your SWR is higher on channel 40 than channel 1, your antenna is too short. Some antennas have tunable whips.

Also bad coax will cause your SWR's to be high. HTH

 

Another thing that can cause high SWRs is if you ticked some one off and they staple or run a wire through your coax, fun how long it takes to find it. Burns up radios pretty quick too. I fugured I,d toss a bit of shet out there for whatever reason. .

 

Factory antennas and coax can be some of the worst ever installed in a vehicle. I would check coax first. Then antenna.

 

I drive a Cascadia. 2008 - 2011 models. There are many threads on here about them with useful info. Most of the antenna systems I've checked on our trucks have high SWR. My companies antenna set up could be different than yours. Our CB antenna is the left one, the right one am/fm. One of our drivers found a bad 259 connector on his coax. After he fixed it he had a good SWR, it makes me wonder about some of the other trucks I've checked with high SWR. The shop has found some of the coax not plugged in well to their little junction boxes as well. On our trucks the coax goes thru 8 junction boxes before getting to the radio!! On our newer ones they have cut that down to 4 junction boxes!! Basically, if I owned one of these things, or was assigned to one truck, I would start with all new high quality coax and a good antenna, some bonding straps, and one of the mirror mounts especially made for the Cascadia.

 

That's great! The more I learn about Cascadias, the more I think the very first thing you should do is check all the coax connections and the PL 259, if you are going to try and use the factory stuff. It's kind of a pain to get to them all, but would probably be worth your while to do so.