Unusual problem (I think). Any advice appreciated.

Discussion in 'CB Radio Forum' started by fastSVT, Mar 22, 2008.

  1. fastSVT

    fastSVT Light Load Member

    261
    30
    Oct 17, 2007
    Louisiana
    0
    I've had dual RadioShack mirror mount antennas on my truck for awhile now. Everything was great. SWR was about 1.5, and I could transmit and receive great distances. But during a bad storm recently, a piece of debris hit my truck and snapped one of the antennas at the very bottom, right above the bracket. So I go to RadioShack to get a replacement antenna and put it on. Now I'm not picking anything up except noise. And here's the weird part, when a vehicle passes me on the road...I can hear their engine through my radio?!?!

    Here's the antenna setup I have:

    http://www.radioshack.com/product/index.jsp?productId=2102430&cp=2032052.2032075.2032078.2032098&fbn=Type%2FCB&f=PAD%2FProduct+Type%2FCB&fbc=1&parentPage=family

    Here's what I replaced the broken one with:

    http://www.radioshack.com/product/i...f=PAD/Product+Type/CB&fbc=1&parentPage=family

    All I did was go into the store and grab that antenna because it looked like the ones on my truck, but the description on the website says it for single use. Is that maybe what my problem is? Without the new antenna on, I can pickup other radios, but not as well as with both. But like I said, when I put the new antenna on, I'm picking up all kinds of strange noise!

    My SWR on ch1 is around 1.7, channel 19 is around 1.3, and channel 40 is like 3.5??

    Can somebody lend me some advice? Thanks
     
  2. Truckers Report Jobs

    Trucking Jobs in 30 seconds

    Every month 400 people find a job with the help of TruckersReport.

  3. thetez

    thetez Medium Load Member

    380
    24
    Jul 10, 2006
    0
    theirs either an easy fix or a "what the heck is going on?!?!" you can check the SWR so you might just need to tune the antenna... the one since the original antenna cant be tuned.... maybe if you think they will let you return it (if you dont need it) buy a 2nd tunable one like the original you have, i wouldn't spend more than 20 bucks on an antenna though when you can get a $20 wilson silverload. but try tuning the antenna that can be, the antennas right now arnt matched, if you cna find the right "length" maybe it will fix your problem
     
  4. 2xR

    2xR Medium Load Member

    365
    94
    Dec 12, 2006
    Ol' North State
    0
    Have you checked the nylon insulator that rest in the bracket? If it was damaged when the antenna snapped it could be your problem. It has happened to me several times. I thought it worth mentioning.
     
  5. kd5drx

    kd5drx <strong>Master of Electronic Communications</stron

    485
    102
    Nov 28, 2006
    Some where USA
    0
    You have 2 options here. tune the one you put on as a replacement since it is tunable and the others weren't. or go back and take the one you bought as a replacement and exchange it for one just like the other one non tunable. The problem is you have mis matched antennas in the same system which will work but not as well as a matched set. hope this helps.
     
  6. fastSVT

    fastSVT Light Load Member

    261
    30
    Oct 17, 2007
    Louisiana
    0
    Hey thanks guys. I kinda though it was something to do with them being mismatched. And thanks for the nylon insulator comment. I'll check that 1st thing. So how do I tune the antenna? I know you're supposed to cut the steel ones, but what about the fiberglass?
     
  7. kd5drx

    kd5drx <strong>Master of Electronic Communications</stron

    485
    102
    Nov 28, 2006
    Some where USA
    0
    One of two ways with out seeing it i would say on the top it will have a cap made of rubber usually. You take the cap off and look at the tip it should have wire wrapped around the fiberglass and a coating over it. You can do the next step several ways but the way i suggest since the one is not tunable is to start with your base line like you said its higher on 40 then on 1 you need to trim it a little bit at a time no more than 1/4 inch at a time and then check your swr again. And keep going till you get it to some where close to equal all the way around the dial it may not be 1.1:1 but as close to that as you can on all channels. Once you get it where you want it replace the rubber tip and i always tape them back on so they are for sure watter tight. Hope this helps. If it has a sliding collar on it some place that would be the other way. Or it may have a screw in the top with a lock nut on it like some of the Wilson's do so just look it over good. to start with and you should be fine.
     
  8. fastSVT

    fastSVT Light Load Member

    261
    30
    Oct 17, 2007
    Louisiana
    0
    Ok I don't see how I'm supposed to tune this thing. I took the cap off, and there's no wire exposed.

    One of the reviews on RadioShack says "it can be adjusted at base"??
     
  9. fastSVT

    fastSVT Light Load Member

    261
    30
    Oct 17, 2007
    Louisiana
    0
    PS: The nylon insulator is fully in tact.
     
  10. thetez

    thetez Medium Load Member

    380
    24
    Jul 10, 2006
    0
    ah... my buddy has one of those..
    and its really not much of an adjustment, their was a bolt or something .. allen key? that needs to be loosened then the whole antenna can slide up or down, i didnt get it to make much of a diffrence when i tried tuning for him, we tried my wilson silver load, it was much better, so he just ended up buying one of those. but thats how, the entire thing slides up and down...
     
  11. fastSVT

    fastSVT Light Load Member

    261
    30
    Oct 17, 2007
    Louisiana
    0
    OK I found it. It's a flat-head screw inside the rubber cap. After a little tinkering, I got ch40 to abou 1.4, ch 20 at around .9, and ch1 around .3. That confuses me though because I thought channels 1 and 40 were supposed to be higher than 19???

    Anyway, it seems like unless I keep my RF gain below halfway, my meter is picking up too much noise. Doesn't seem like it did that before?
     
  • Truckers Report Jobs

    Trucking Jobs in 30 seconds

    Every month 400 people find a job with the help of TruckersReport.