Turned up 2 pots on my 1993 Cobra 29 LTD Classic

Discussion in 'CB Radio Forum' started by jimbowilly, Aug 26, 2011.

  1. jimbowilly

    jimbowilly Bobtail Member

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    Aug 15, 2011
    Troy, NY
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    Hi,
    I had a 1993 Cobra 29 LTD Classic turned up at a local cb shop in Grand Rapids, MI. In the same year, 1993.

    I watched the tech. He turned up 2 pots/shielded coils. Nothing else. Then he checked my swr on my antenna set up. I paid him $35. And I was good to go.

    On a quiet day I have spoken with other trucks anywhere from 7, up to 12 miles away. I used that radio for 6 year, daily. The best deal I have ever gotten for $35.

    This tech cut nothing, added nothing. He just melted the wax and adjusted 2 coils on the speaker side of my radio.

    What 2 pots did this tech adjust? Any idea?

    Thank you,

    Jimbo
     
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  3. WA4GCH

    WA4GCH Road Train Member

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    Aug 12, 2009
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    :biggrin_25513: The dollar and cents pots :biggrin_25513:
     
  4. Turbo-T

    Turbo-T Road Train Member

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    May 31, 2009
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    Without seeing what he was doing it's hard to tell. There's so many pots inside of a radio...there's one that brings in the receive, one that adjusts the meter, one that adjusts the squelch...there's also a modulation pot, I'm sure this was probably one of them he turned.

    Did this so called tech put the radio on an oscilloscope? Did he also have said radio on a signal generator?
     
  5. WA4GCH

    WA4GCH Road Train Member

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    :biggrin_2556: A O C YOU SCOPE and a SEE U GENERATOR :biggrin_2556:
     
  6. Rat

    Rat Road Train Member

    Some places just take them slugs right out. Then adjust VR 4 a little and call it good.

    If you are not too worried about bleeding onto adjacent channels then this works OK. Knowing what I know now, I would not have paid even 10 dollars to get this done.
     
    CBSPARKY Thanks this.
  7. jimbowilly

    jimbowilly Bobtail Member

    37
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    Aug 15, 2011
    Troy, NY
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    Hey Rat,
    One morning around 04:00 while I was following another driver in my truck. Talking over our cb's. A ham joined in our conversation. He stated he found the channel we were using by following the bleed over from my peaked and tuned cb radio. So you are right on the money.
    Just seems a person could obtain a stronger, cleaner signal from a cb radio without using an amplifier. I know of shop modified cb radios putting out 35 to 40 watts, without any noticeable bleed over.
    Best of Luck w/Irene
     
  8. Rat

    Rat Road Train Member

    Yea, the slugs he turned were L14 and L16. He might have spread the coil at L12 just slightly also. The VR pot that they adjust , if they don't clip D11, is VR4. They turn this counter clockwise. Some will turn it full counterclockwise which is way too much. 3/4 is about all that is needed.

    As far as the 35-40 watts, well I have heard it done, never seen it done but I have heard it requires the replacement of certain parts inside the radio and one of them is swapping out the final transistor with a better one. I know there is a vast amount of info on the net that can get a person what they want out of a cobra 29. It all just depends on how competent you are with a soldering iron.

    As far as the bleed over, I have heard it myself from other operators. Sometimes it is not too bad and they are only bleeding over to the next channel. I have heard some bleed over 5 different channels. But usually they are real close and the bleed over quits once you get some distance away from them. It kinda sounds like the teacher on the Peanuts cartoons. LOL But when you find the radio that is bleeding, you will know it as it is usually real loud when you find the channel they are on.

    I have only heard one radio that was so bad that he was drowning out local transmissions. It was a guy running down the road talking with another driver that was less then a mile in front of him. I politely broke into his convo and asked him if he was running any power. Found he was running a tuned cobra 29 into a linear. I explained the situation to him etc. That he was bleeding real loud on to the next channel and was actually drowning out or stepping on convos on that channel. He was real nice about it and turned off his amp. Problem solved and everyone was happy.

    Around my area, bleeding radios don't seem to cause too many problems, especially out in the boonies. I can see it becoming a problem in highly populated areas with a huge amount of truck traffic though.

    But it sounds like you are happy with the results from your radio and that is a good thing.

    I, personally, have absolutly no problems with stronger then stock radios unless the user of the radio is a dillweed and only using it too harass others.
     
  9. jimbowilly

    jimbowilly Bobtail Member

    37
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    Aug 15, 2011
    Troy, NY
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    It's "$35". Not "35 watts".

    I said the guy in Grand Rapids, MI charged my $35 to peak n tune my 29.
    Actually this tech set my carrier to 7 watts, with a 12 watt peak.

    I used a 4 1/2 ft Francis antenna, 18 ft of coax, mirror mount mounted on a chrome plated steel mirror bracket. Which was mounted onto a truck cab made out of much more steel than you will find on today's tractors.
     
    Rat Thanks this.
  10. jimbowilly

    jimbowilly Bobtail Member

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    Aug 15, 2011
    Troy, NY
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    That would be awesome! $35 for 35 - 40 watts on a Cobra 29 LTD Classic.
    Wouldn't every trucker dream of getting a run up to Grand Rapids, MI.
    "Wow! Dude, your radio sure sounds great!" "Thanks Man! I got is "Peaked n Tuned" by that tech up in Grand Rapids, Michigan".
     
  11. WA4GCH

    WA4GCH Road Train Member

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    :biggrin_2556: Yep just what you need :biggrin_2556:

    Now how much of that 35 watts is trash not signal ....
     
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