Ok here is the scoop. I was running dual 4' Wilson "Silver Load" FGT CB Antennas. I had them tuned to around 1.5 on the swr. Now that I have gone down to one of them the swr is now at 2.5. I am using the same mounting setup I did before and connecting the little ground wire only made it worse. Here is how I have them mounted,

Would mounting them directly to the stake pocket be better? Or what could be my issue. I just bought some coax from radio shack, because the radio shop I bought the antennas from in the first place is now almost a hour and a half away. I might run up to the truck stop and see if they have any but that would mean the intertor has to come out again, and I just did that last weekend. So what are my options?

 

Have you grounded the body to the frame?

Are you using a single piece of coax?

I'd suggest an 18ft. piece of quality coax (not the Radio Shack stuff) and ground the bed to the frame with a ground strap or 2.
Many times just getting a better ground will drop the SWR to where you want to be....

You might want to remove some of the paint under the bolt you have mounted to the stake hole to get more ground contact.

Rob

 

I want to say there are a few straps on the bed and I'll sand a little under the bolts tomorrow. But why would the swr change that much from a dual to a single? I will go and look at the truck stop and see if they have a decent set of coax there.

 

Coax length will also play a big part in SWR so if you're running duals you will have 2x the coax.
You probably got a good reading because of all the extra coax.

I'd run a new 18ft coax and start from there....also don't trust the built in meter in any radio to be accurate, try to use a separate meter.

Rob

 

Oh I know that! I have an external swr tuning meter that I use. I don't use the radio ones at all. I will try the suggestions you gave and I will update as soon as I get the swr in range

 

Your cable looks identical to one I used to run, and I think maybe your cable is backwards (don't hate, read on). It looks like it has a micro-conector below the regluar coax connector. The micro-UHF connector will be the weak link, anything getting inside it can cause a jump in SWRs. If you don't want to flip the cable, heat shrink it or put some silicone on it to seal it up. Buying a better cable is a 100% good way to improve your rig, especially if you're stepping up from a non-quality cable.

And run grounds to multiple parts of the truck. The more grounds the better the plane usually. So hit the bed, the frame(grind off any coating), the cab, etc.

Something else, running true duals on a truck that sized can cause your transmission strength to drop even if you have great SWRs. And depending on what kind of harness/connectors you're using you could also be reducing the power before you even get to the antennas. So if you're running a legal box pushing 4 watts, your transmit power is gonna be nil. If you're running a heater, you might want to go to a single stick and buy a Predator or something similar. If you're running a small mod (10-30 watts) just disconnect one antenna and run a dummy if you're going for a look.

Previous Rig 1: Cobra 19 to a radioshack mag-mount disaster.
Previous Rig 2: Cobra 25 stock, 18ft of craptastic RS coax to one 4ft Francis.
Previous Rig 3: Cobra 29nw modded to 30, 18ft cophase Firestik firestuc to dual FS4s.
Current Rig: Cobra 25 modded to 30, 18 ft of Firestik firestud coax to a 5.5ft Francis. Pulling 1.3:1 on a good day.
My Rig in the works: Cobra 25 modded to 30, 18ft of shielded coax to a Predator dual coil w/ 22in shaft.

 

See I have changed the set up. That picture is from the first set up(duals) and is the oppisite antenna I am using. Just a pic to show how it is set up. I am runing a stock radio and its just some normal coax bought at rad shack. Tomorrow I am going to try and clean up the area behind the washer and see how the bed is grounded. Never had this type of problem before. Would running that ground wire off the antenna to a different spot work just like grounding the antenna or is it a seperate ground?

 

That cable was a pre made dual cord so it can only go one way. I am going to try and locate some new cable tomorrow and try that as well. I might just say forget the interior removial for now and run it like I did the first time for now. Once I get more time to do the interior again(maybe convince they guys at the ATNs to help) I will re-run it up and under everything again.

Going to try the grounding thing tomorrow

Now as for the tuning tip would trimming it even shorter help? I dont want to get too crazy right now when something as trimming a tuning tip would be the fix.

 

I'll post the Firestik FAQs again. They're the best out there for free IMO.

 

ok well they were trimmed once already while trying to tune the duals and they were not even in the antennas when I got my 1.5, nor is it right now.

 

The Firestik everything-CB page. Tech-Docs Index

It's all good. Tuning a tip doesn't necessarily change the SWRs the same across all 40 channels. It changes the slant of the plot. When your SWR on CH1 is higher than CH40, you're short, and you have to move the wrapping of the coil to try to compensate (read: hard). If its viceversa and Ch40 is high, then you're long and you trim off a bit of the coil. The goal is that SWR reading is lowest near the chanel you use the most (19 is the most common).
http://www.firestik.com/Tech_Docs/swr-plot.pdf

So the cable can't be backwards (mine was a single, looks identical from the pic), but that conenctor can still be problematic if you don't protect it. Def get some better cable like yo said you might, it's almost always a good investment(and usually one of the weakest links in the system).

 

Sorry keep forgetting things. I was told to trim the tips by the shop I bought the antennas and stuff from. After taking a fery little off he suggested trying to tune them with out the tips and it worked great. 1.5 was the highest I got through the channels.

 

Wait your antennas have tunable tips right? You didn't have to cut anything?

 

Yea they have tips you can move in and out. I thought it was wierd but the radio guy suggested it and so did the instructions for the antennas.

 

I'm reading that link you gave me and I think I simple jumper to one of the four mounting bolts and down to the frame will cure the grounding issue. Instead of removing a large amount of paint not to have it work.