I give up....

I'll bet that you've got one or more devices that are interfering with your radio reception then.

 

It's the elog tablet.... throw that pos out the window

 

OK

a couple thoughts, maybe some one can counter them with some sort of knowledge.

first thought.

Measuring SWR seems to be the big deal to many, one thing that they are measuring or thinking they are measuring is the reflection of a mismatched load on the other end of the coax, which includes the coax itself. IT does not in most of these cases of the CB in a truck. The reason is from my experience is only the load is mismatched, the coax is at the impedance that the radio is tuned for (50 Ω), AND because the coax is less than a wavelength, the coax becomes part of the radio system and not the load. I know this may sound wrong but it isn't. SWR wasn't a popular measurement until the 40's and it was really not taken seriously until the 50's.

Having a low SWR means little if the "range" of the transmission is less than say 8 miles (I have talked to people all over the world on a few watts and a random wire stuck out the window with an SWR of 5 to 1). If you get a 1.5 to 2 miles, then there is a problem. It could be one or another thing to do with the radio itself or the antenna system but you won't find it staring at the SWR meter.

Going hand in hand with this, is the antenna. Not too many times the antenna is actually guilty of the problem, a lot of thought goes into it, and because trucks haven't really changed in decades (other than the material used to make them), the chances are getting a bad antenna is slim. What a lot of people do not do is seal the end of the connector, and/or use a good mount for the antenna and when things go wrong blame the antenna itself. I've seen this happen when a little water gets into the coax connector because it isn't sealed (crimp on ones) but they have a great SWR because all the power is being absorbed by the water in the coax. Then finding the problem when using another piece of test equipment solves the issue and the radio works as it should. So ... I have good luck with good antenna mounts that are not cheap, I recommend that to start with. The mounts can also have a moister issue with the plastic washers. I also use a coax connectors that are not crimp types with a coax sealants but also use a silicone sealant on the mount itself. By the way, I had a few custom mounts made, one for F type connector and the other for an N type connector. Both of these coax connector ends can be bought with seals in them to seal the connector's center from the outside, both of these mounts worked really well and never had to use a sealant with them.

Second thought is the noise, I blame the radio for a lot of this. I know many spend a crap load of money to get a superduper radio (I have had all kinds so I know what they are) and many times they collect noise because of one defective design or another or worse yet ... a magical tech who thinks he knows what the hell he is doing. I've got a realistic TRC-52 (look it up) and it is one of the best radios I have had to deal with noise. It was put into my truck and all the crap that my galaxy and my other radios picked up was gone. I don't know specifically why it worked but it did. I have others radios (something like 100 plus on the shelves - I seem to collect them everywhere) and many of them put into the same slot, pick up noise. Some of the more expensive ones are the worst but some of the cheaper ones are up there too. SO after messing around with the noise issue for months, trying many many different power configurations, filters (commercial and homemade), grounding everything in the truck, using isolated power (battery), and using all kinds of test equipment, two things I concluded - 1) it depends on the radio, 2) it is frustrating.

 

In the 40's & 50's most antenna lines were ladder lines where high SWR can be tolerated.

Once a load that is not the proper impedance the coax reflects that back toward the radio.

kc0iv
leon

 

No, just been there and done that! I didn't make up the info in the post about the Cascadia or read it in a book. That was all trial and error on my part. I don't care what you do and whatever you do may work as well, but I passed my info on to be helpful If you succeed I hope you pass your info on as well. (If you stay stuck on a Wilson antenna, you won't) Remember, a Dummy Load has a perfect SWR reading also.