Cannot Tune Cobra 29 NW LTD Classic

Discussion in 'CB Radio Forum' started by jbiggs24, Nov 17, 2009.

  1. jbiggs24

    jbiggs24 Bobtail Member

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    Jun 5, 2009
    Detroit,MI
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    Hi,
    I recently bought a used Cobra 29 NW LTD Classic that is in like new shape and hooked it up to the rig with the company supplied antenna and I could not get the SWR's to tune in below 3. I figured it was the antenna or coax so I went and purchased new cable and also a Wilson 1000 watt antenna. I hooked it all up and I am having the same problem, it got a little better but the SWR'S are still high and now just a tad below 3. What do I do next ?? Could it be the radio ? If anyone has any ifo that could lead me in the right direction I would really appreciate it.

    Thank you
     
  2. josh.c

    josh.c Road Train Member

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    Feb 22, 2009
    Knoxville, Tn
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    What kind of truck are you putting it on? Are the new antenna and the new coax on the factory mount? One possibility is that the mount isn't properly grounded.
     
  3. FriedTater

    FriedTater Keeper of The Snakes

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    Mar 25, 2009
    United State of Texas
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    You need to trim the stinger down about .5" then recheck it.
    If you can get "the radio" to show under 2 your in decent shape.
    You need an SWR Meter to bring it down further.
     
  4. Izlomik Supatrucka

    Izlomik Supatrucka Light Load Member

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    Oct 24, 2009
    Texas
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    Your radio has nothing to do with the Standing Wave of your antenna......

    If your running the factory coax, dont....change it out with some good coax....dont go to a truck stop
    and get any of that junk either find a ch shop and get some Beldon RG8.....you do need a external
    swr meter to set your SWR (there is only 1 standing wave no shuch thing as SWRs lol) if you dont know
    what you are doing it is probably best to have the shop that you get your coax from tune your antenna for
    you.....someone can explain to you over the phone but like i said its just as easy to have the shop do it
    if they will do it rite....that getting your SWR below 2 aint guna cut it.....if its grounded properly and you
    have good coax and good antenna you should be able to get it to 1.3 or better and thats where you need
    to be......if your ever down around East Texas ill show you what a perfectly tuned antenna with no
    reflect will do....hahahaha all the locals know....just holla for DC:biggrin_25525:
     
  5. WA4GCH

    WA4GCH Road Train Member

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    Aug 12, 2009
    Seminole Florida
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    Put a LOWPASS filter on the radio to filter out trash if the SWR goes down your radio is spuing put garbarge a common problem after the radio hacks get done with a good radio.

    you can see some of my filters on good radios.
     

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  6. WA4GCH

    WA4GCH Road Train Member

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    Aug 12, 2009
    Seminole Florida
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    IF THE RADIO IS SPUING OUT TRASH IT WILL READ IT AS A HIGH SWR

    Try a filter borrow one and if the SWR goes down thats thew problem ....
     
    josh.c Thanks this.
  7. Izlomik Supatrucka

    Izlomik Supatrucka Light Load Member

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    Oct 24, 2009
    Texas
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    how is the radios tune job guna affect the standing wave of the antenna?

    a radio isnt going to spew trash with just a carrier.....if your talking into your radio
    while checking the standing wave then yes it can afect the reading you get but....
    you arent supposed to modulate while checking reflect of the antenna just a carrier
     
  8. WA4GCH

    WA4GCH Road Train Member

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    Aug 12, 2009
    Seminole Florida
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    ASUMING ....

    The antenna shows a better match on a stock radio .....

    This problem has been hashed out before IF you have a ground at the antenna ande a 2nd radio shows a good match your radio is spuing out trash which the antenna shows as a high SWR.

    This is why I recemended a low pass filter since it will make shure your radio is clean ...... NO TRASH ....

    Try another radio if you get the change in SWr then supect a badly tuned radio if not then recheck your antenna ...

    In the photo you can see one of my filters upper right next to weather station display.
     

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  9. Powder Joints

    Powder Joints Subjective Prognosticator

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    Sep 25, 2007
    Rosamond, SoCal
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    I realize this post is old, but it still a bunch of crap. SWR has to do with frequency resonance not garbage generated by the radio.

    Could be bad grounds, open or shorted coax, ant mount, or poorly installed connectors. Just because this poster is a Amature does not mean he knows what he talking about, thats why they dont call them professionals.

    And yes I have a class a, and a NABER Cert, and a extra class.
     
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