Troubleshooting my CB setup

Are you checking the SWR with RF and mike gained turned up or turned down? I check mine with both on and off. With my built in meter on my 959 I showed a 1.2-1.3. Also what are your readings on channels 1 and 40?

I recently sent my radio off to snakeradiocustoms for a tune up as it was 3 years old and needed some help. I have bonded the just about every panel and part on my 07. Best bonding material is coaxial shielding.

 

I find it hard to believe that the antenna ground is the issue. The metal around the antenna (bed, toolbox, cab, etc.) provides ample ground plane. I've seen the same effect accomplished on fiberglass vehicles by gluing aluminum foil under the fiberglass in a star pattern under the antenna. The foil was grounded via the coax sheath and nothing else. It worked fine and SWR readings below 1.2:1 were possible. Extra ground wires run to an already grounded truck bed are nothing more than electronic voodoo. The truck bed provides plenty of ground plane as it is and the antenna is grounded by the outer sheath if all else fails.
I'm with LUSETACO, fiberglass antennas either work or they don't. There is no in between with that fixed coax/antenna setup. Fiberglass sticks are neat because they're simple and tough but they suck because you're stuck with the impedance between the feed line and that non-adjustable element.
Short of adding a full wavelength's worth of coax into the system (along with the included loss of RF strength) , there's not much you can do to "tune" that setup. Saying a 14 gauge ground wire run to an already grounded bed will fix a high SWR reading but a 16 gauge ground wire will not work; is snake oil stuff.

 

Plastic bed = no ground plane. Even hanging off the back of the truck is a better mounting location. At least there you have the tailgate and the ground to act as a ground. In the bed there is not enough metal. Not all CBs and antennas are going to match up. Sometimes you need to just toy around with different setups until you find something that works.

 

Hate to tell you this but no vehicle is a good ground plane the plastic bed has little effect there is plenty of metal to provide enough ground plane to work. Adding ground wires to an all ready grounded mount will not help I know it makes people feel better but it doesn't, do sh--. Adding or subtracting coax does not work if the swr is out to lunch there is some thing wrong with the install or the antenna. I run a 100watt ham radio in my truck it has no ground wire I don't know how long my coax is other then it makes it from the front to the back I had no need to measure it. I have no problem talking to Europe pretty much every day. The antenna is not plastered against the cab. I do not use 11meters but I do use 10meters and there is very little difference.

 

couldnt all be avoided my using a NGP antenna? lol

 

I never said any vehicle was a good ground plane. Just stating that the plastic bed of Tacomas is probably the worst spot to mount a CB antenna.

 

AllMotorRex: I did not find a bolt on mine where your picture showed, did you use a self-tapping screw to put it there? I'm working on this today, and hopefully will have some feedback on the results later on. If this doesn't solve the problem, then I will try some of the other suggestions. However, my setup is very similar to yours, so hopefully this is my issue.

 

Yep, I used a self tapping screw. Scratch off the paint and drill that bitch in. Just so you know, my exact situation went like this ....... I installed everything with a #12 wire and best I could get was in the 3s. I did absolutely nothing but change the wire to a #8, grounded in the exact same spot, and first test I got a 1.2 between ch. 1 and 40. I haven't touched it since then.

 

Also if that doesn't work, make sure that your antenna is mounted correctly to your mount. Should look like this ........

 

I completed the ground wire installation directly to the frame. That was a huge part of the problem as I suspected. I am no longer pinging way up into the red above 3. I've got it adjusted to a 2.5 on 1 and a bit above that on 40 now. I need to make more adjustments though. At least that's a step towards improvement in the correct direction now! I used 10 gauge wire for the ground, I wonder if that is making any difference. Wondering now if I should have used something bigger.

Edit: Yes, my antenna post is just as you show in that diagram.

Update: I made minute adjustments until I ended up just trying the antenna with the tunable bolt removed and just the red cap on top. Surprisingly enough to me, this got the best readings I could manage: 1.5 on Channel 1 and 1.9 on Channel 40. Still not perfectly desirable, but it is at least within a safe operating range until I can mess with it further.

 

Yes if you put it in the middle of the bed! Everything RF is a compromise when it comes to vehicles but there are places to put an antenna that are better than others. Against the cab is probably the worst, a 4' antenna on the roof maybe electrically good but not much good in parking garages or the woods, on the side of the front fender is no better than the rear bed corner and you have to look at it while you drive. I was 16 when I had my first CB yes back then you even had to have a license for CB radios that was 51 years ago. I do not tune systems/antennas with a Radio Shack SWR meter I use a $1600 Bird AT100 antenna analyzer. Many years ago cars and trucks were poorly grounded because it didn’t matter now with all the electronics in modern stuff grounding is very important all the frame work, exhaust, body panels etc. are well grounded so a plastic bed is just a covering for the ground plane. Again if a ground wire “fixes” an install the mount was not grounded in the first place.

 

Go to firestik.com they have a help/tutorial page that will tell you all you ever wanted too know about antenna mounting and how to trimm for the lowest SWR's

 

Well, I have an update on my setup. I got tired of screwing around with the Firestik antenna, and partially took the advice of the "Buy a Wilson Mag mount and be done with it" crowd. I bought a Wilson 2000 "Trucker" antenna (Same length as the Firestik), put it on my now properly grounded mount, an tested the SWR reading again. Made one adjustment to the whip, and it ran a 1.1 on Channel 1 and a 1.6 on Channel 40. Not perfect, but better than anything I could get the Firestik to do after messing around with it for hours.

As for the mounting location, I purchased a maneuverable RAM mount to install the radio in the cab with. I am picking up interference when I press the brakes, and when I lower or raise the windows. Even running both the power and ground leads to the battery didn't eliminate this occurrence, although it did seem to stop the windows from interfering. Any ideas on this issue? I read somewhere about adding a ferrite choke to the power lead to help address this. Has anyone else had any success with anything like that? Seems like a cheap thing to try anyway to see if it helps.

 

I have a 3' Firestick II at the back corner of my bed, my SWR is between 1.1 and 1.3 on all channels.

Pics of location are in my TW photo album.

 

Good decision on the Wilson, much better antenna. As far as the noise just make sure none of the power wires or the coax aren't along side any other wires from the truck. You could try an inline noise filter buy I've never had much luck with them.