Firestik II Antenna Tuning ?

So I just had a

$125 Uniden Bearcat 880 CB Radio with 40 Channels and Large Easy-to-Read 7-Color LCD Display with Backlighting, Backlit Control Knobs/Buttons, NOAA Weather Alert, PA/CB Switch, and Wireless Mic Compatible

Uniden Bearcat 880 CB installed in my truck yesterday. It has an SWR meter built right in.


I also had a Firestik III 3ft antenna installed with a spring mount. It's installed over my hood so I can use the hood and rooftop of the truck for ground planes.


I spent 45 minutes last night parked in the middle of a dirt lot trying to tune my antenna. I absolutely cannot get both Channel 1 and Channel 40 below an SWR of 2 at the same time. I've gotten Channel 1 down to 0.5 but then Channel 40 is 3+. I simply don't get it.

I'm going to see if I can borrow a multi-meter at work today and attempt to test my antenna mount to see that it's grounded properly just in case that's an issue. The installer hooked the negative ground to the same body ground that Toyota hooked the vehicle battery to. So in theory that should be fine.

I'm using a Firestik Fire-Ring for my coaxial - however due to the short run I ordered their 9ft cable as I'd read the shorter the cable the better. However, I'm now reading that 18' is the overall recommendation. I have not confirmed with my installer yet whether he had any extra coaxial that he coiled up - I've read that coiling it up in a circle causes interference issues.

Any extra ideas/advice?

 

Check for small coiled up excess coax, good ground. 2:1 on 1 & 40 isn't terrible but should be able to do better. Also, if your coax cable came with the pl-259 connector not attached, make sure it was assembled right.
Firstik actually has a good write up on CB antenna tuning, have you checked that out?
http://www.firestik.com/Meas-SWR.htm

 

I'm using a Fire ring. No assembly of coax required.

I've read their guide several times. Plus those of other sites. The small bit of excess coax was in a circle under the console about 8-10" in diameter. One loop around. A foot less coax and there'd be no slack.

So far as ground. The metal mount the antenna is bolted to shows 0 ohms when check with the grounding point where the CB negative cable grounds to the body (same place the vehicle battery negative grounds).

 

hmm, Do you have a mag mount antenna you could hook up to troubleshoot the radio out of the equation? And/or an external swr meter ?

Edit: would also check the coax cable to make sure it's not shorted. use a multimeter to check resistance between center and shield. Should be none.

low swr on chan 1 with higher on 40 would seem to indicate you need to shorten the antenna. I presume you've tried this?

 

I've adjusted the antenna tip to both extremes. It is a Firestik II.

I'm told there is a guy in town who does SWR tuning professionally but I haven't gotten his contact info yet. Nor time to deal with it. LoL

 

ever get this figured out?

 

@WileECoyote

 

LOL!!! Hey Ron!!!

To the OP, I would try an external SWR meter as some one else has already mentioned?! The 18ft cable lenght is a CONSTANT on-going debate for sure!!! I have my cable coiled and have NOT seen any reduction in capability?!

A SWR of 2 is not that bad, but agreed, you should be able to knock it down farther???!!! I would still recommend looking into the cable setup as that is usually the issue.

One other thing to note, there is also debate about whether the SWR meter be at the radio output side OR at the antenna side!

Finally, it really does make a difference if you're not putting the antenna "top cover on" for each tuning adjustment!!! It needs to be put back on for each tuning adjustment check!!! One thing is for sure, you are doing it correct by doing it in a wide open lot!!!

Hope this helps?

Happy Wheel'n