Getting very high swr

WildTxn, by mounts being frequency sensitive, I assume you are referring to the mag mounts that have wiring coils in them designed to match up with a stinger of a certain length to provide for CB band usage, as opposed to a "dumb" mag mount that is just the magnets and a housing that contains no such wiring coil, in which case a 102 / 108-inch stinger should be used for the CB band. Is that correct?

 

Well those wiring coils would be considered as internal load coils, and their purpose is to allow use of a shorter length antenna. But, they will also block and absorb some xmit power. That's separate and not part of the capacitive coupling part of the mount for the ground plane. If you could remove that internal coil (or short across it) and keep the capacitive coupling element in place and in circuit, then you could use a full length whip and get the max xmit power. You will still need to fine tune SWR though by playing with the length of the whip, or using an inline antenna tuner.

 

Its getting deep here.

 

Based on that reply..We know the problem..

 

If your sure it's not the antenna, then you may have the wrong type of COAX, or damaged Coax, or a damaged output stage in the radio. High SWR is simply the result of a severe impedance mismatch somewhere between the output stage and the air. Also check all connectors. Remove any splitters, diverters, RF switchs, etc..

Also, I don't know what type of radio you have, but some base station CB's are designed to use a BALANCED antenna system. You may need a BALUN.

Now... before going any further, lets get into the COAX. Most COAX sold since the turn of the millenia has a FOAM core. This stuff has better RF properties but is easily damaged. Us old timers hate that stuff because you can't solder it. Any tight bend or kink has severely altered the impedance of that cable in that spot. Look at all of the numbers on your cable and I can tell you what you have. Sneaking the cable under the truck door seal can easily foul up your "state of the art" cable.

Get an ohm meter, set to lowest range if not automatic. Unscrew connectors on each end of your COAX and isolate your COAX. Place one lead on outer (ground) section of the RF connector on one end of COAX, then stretch and place the other meter lead to touch on the outer (ground) section on the RF connector on the opposite end of the COAX cable. If you anything more than a few tenths of an ohm, you are the victim of aluminum shielded COAX.

You can also get your spare, known to be working CB, and a new length of 50 ohm COAX 10 to 20 feet long with pre-installed RF connectors, and a known working antenna. Plunk the antenna down on square in the middle of your personal cars metal roof, hook up the COAX keeping it relatively straight, SWR meter, and CB. All outside! Use jumper cables to get 12v to the CB. Test and confirm good SWR. Now, one by one, swap out components with your troubled system. Won't take long to back the trouble maker into an inescapable corner!

 

And I posted him a picture! He never commented about it . The dude is a troll I'm thinking.

 

Have you done this yet?

1476540202611_zps9kkgfdxe by rabbiporkchop posted Mar 10, 2018 at 5:15 AM

 

That won't help rabbi.