Cobra 29LTD Classic questions.

Discussion in 'CB Radio Forum' started by Lysdexis, Nov 14, 2018.

  1. x1Heavy

    x1Heavy Road Train Member

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    I remember those. The speakers.

    Found a goodie once hooked it to my Uniden and it was collecting stuff I could HEAR A MILLION MILES AWAY.

    None of that crappy stock speaker. (Which itself aint bad, but boost it to 90 Db for me....)

    Not a million I think some nights quiet I could get out to 15 miles give or take a little bit. Lake Havastu comes to mind. The blater blah blah 15 miles before I get there.
     
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  3. Bledfor Days

    Bledfor Days Bobtail Member

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    Cheap phone chargers can generate noise radios will pick up too.
     
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  4. Meteorgray

    Meteorgray Heavy Load Member

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    That picture in post 18 makes me cringe. The antenna is not only low, but the adjacent metal looks like it would be detrimental to any RF in the area.
    That picture makes it appears that the antenna is challenged by not only height, but also metal close to the coil etc. Neither is good for RF communications.
     
  5. Slowmover1

    Slowmover1 Road Train Member

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    Mounted on that headache rack would be better.

    Antenna height no more than 13’5”

    A different antenna may be called for.
     
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  6. Lysdexis

    Lysdexis Road Train Member

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    Only get the noise with the inverter on so guessing that's the culprit.

    So do you suggest moving the antenna to the rack and shortening its overall height to stay at 13'5?


    I appreciate all you guys help I'm cb illiterate but can pick up things quickly if someone teaches me what I need to do.
     
  7. Night Stalker10

    Night Stalker10 Road Train Member

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    No, don’t waste money on a peak and tune job, it won’t make any difference with your inverter noise problem. Don’t blame the antenna, it’s just doing its job. You can verify that by unplugging your coax from the back of the radio while the inverter is on. If the noise goes away, it’s not an electrical problem through the binding post.

    The big problem I see is the location of the antenna. The metal from the vehicle needs to be under the antenna, (as much as possible) not beside or around the antenna. Unfortunately with today’s plastic trucks and mirror mounts, that’s not always possible. You may not have a choice but buy a shorter antenna such as a Hustler FG27s (that’s what I use on the pete I drive, and mount it on the mirror, if it’s the old conventional style mirror mount. Plus run a separate coax. I’m not saying this will get rid of the electrical noise, but it should be a big improvement getting out farther, rather than trying a peak and tune.
     
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  8. Lysdexis

    Lysdexis Road Train Member

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    Peak and tune wasn't related to the noise issue, I will try unhooking coax in a bit and seeing if noise is still present. (Update: no noise with inverter on and coax unhooked)

    If it's gone what do I need as far as coax in order to make it stay gone? Run it differently or get a different one all together.

    And I'll likely move the antenna anyway since it's between two pieces of aluminum (I'm guessing the back of the sleeper is aluminum) And it's got the plastic mirrors so a mirror mount wont work and it doesn't have the studs to put one of those style mounts in either.

    Next biggest issue is being able to get the darn thing off because I cant reach it.
     
  9. Ridgeline

    Ridgeline Road Train Member

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    Try putting a choke on each end of the coax because this may be a case of a common current mode problem.
     
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  10. Night Stalker10

    Night Stalker10 Road Train Member

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    The internal swr meter isn’t very reliable, you need an external swr meter which is more accurate.

    Ridge made a good point, it very well could be a common mode current problem.

    Basically I just didn’t want you wasting money on a tune, since the radio isn’t the problem.
     
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  11. Lysdexis

    Lysdexis Road Train Member

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    What's a choke?
    Common mode?
    And yeah I knew the meter in the radio wasn't dead on accurate but figured it at least was better than nothing.

    Also the tune question was more or less curious if it was worth it at all not just in regards to my issue
     
    Last edited: Nov 16, 2018
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