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Mobile 102" whip tunes great, but other antennas won't

Discussion in 'CB Antennas' started by buickid, Jul 8, 2020.

  1. buickid

    buickid Active Member

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    Thanks for the input Andy, it does indeed look like the roof sheet metal is sparsely connected to the actual frame of the roof.

    Current situation, he has built something of a trombone antenna match at the base of the antenna and has it adjusted to be pretty close to 1.0 SWR. Not sure where the resonance stands.


     
    Slowmover likes this.

  2. Handy Andy

    Handy Andy Do Your Research First, Then Decide...

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    The bummer part is the surface area - where the antenna can generate that image to help with and use for the counterpoise and "missing half". That can appear as or - is just a teensy bit too "small" to get good results - so again the use of a "tuning ring", stub or trombone as a "gamma" to offset the hit against the system.

    This is also in the realm of where some people fell-into, felt and still believe - that Coax length does matter.

    So to me, this area, even with whip at the right resonance, if the other half is not quite able, the coax being 50 ohms ON TOP OF the whatever feedpoint impedance that antenna appears as at the mount, tends to make the multiple-fraction of wavelength for coax-use (think of BALUN) a viable option versus the "Gamma" or otherwise relocated antenna whip to a corner or side edge, or even elevated to change the feed point to match and offset the otherwise shortened counterpoise.

    It's when you try to use power, does this effort start to become unmanageable.
     
    tecnicoloco and Slowmover like this.
  3. Recon

    Recon NY 881

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    Just my two-cents here. I tried just about every CB mobile antenna combination on my 2019 Aluminum F-350. I thought the Predator 10K with the stake pocket mount would do the trick, but could not get a decent SWR. I installed a Breedlove Stake Pocket Mount #910 with a Breedlove Quick Disconnect Coupling #203, a 102" whip and a (total length) 4-1/8" stainless steel coil spring. After assembling the whip and spring to the Quick Disconnect Coupling, the total length was about 109" and a SWR close to 1.6:1. I removed the two retaining set-screws at the base of the whip and trimmed-off (Dremel Tool) to obtain a total length of 108". SWR on all channels is 1.3:1 to 1.5:1. I am a firm believer that the whip is "the way to go" on pick-up truck. When not in use or entering the car wash, I disconnect the coupling and antenna and store it in the bed of the truck.
     
    undertaker likes this.
  4. undertaker

    undertaker Undertaker

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    102 is the best for a pickup...
     
    Slowmover likes this.

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