whats the best tool to trim...

Discussion in 'CB Radio Forum' started by mickeyrat, May 21, 2014.

  1. mickeyrat

    mickeyrat Road Train Member

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    bought a bolt-cutter today.

    Question, is it better to tilt forward a bit before cutting the whip down to see of SWR comes down some? At present its tilted forward by about 10 degrees or so. IIRC SWR is at 2.5 or so with doing nothing to it?
     
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  3. delta5

    delta5 Road Train Member

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    One of the Wilson Antenna engineers told me that CB antennas need to be straight up and down. Tilting them forward does nothing for you but screw up the radiation pattern of the antenna (not to mention making you look like a ######...).
     
  4. mike5511

    mike5511 Road Train Member

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    Don't tilt it passed 22 degrees, the wind will blow it back almost vertical anyway. So even if your SWR drops, it will go back up when you drive down the road. But yes, I would play with the tilt just for fun. You might get a great SWR at 45+ degrees, but it won't talk worth a hoot. Vertical is the optimum, but a little tilt won't hurt a thing. One thing noteworthy; if you are adding your own antenna be sure and remove the factory antenna. I can put a antenna on the mirror mount, on a Cascadia, and leave the stock antenna in place on the sleeper and get 2.5:1 SWR. Remove the stock antenna and it drops to 1.4:1. Just thought I'd throw that out there.
     
  5. mickeyrat

    mickeyrat Road Train Member

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    Really? Whats the cause of that? Still a signal draw with no cb hooked in line?
     
  6. MsJamie

    MsJamie Road Train Member

    Carbide cutoff wheel in a Dremel. Score a line around the whip where you want to cut, then chuck it in a vise and smack it with a hammer. It'll snap right off.

    I've seen antenna whips leave dents in the jaws of bolt cutters.
     
  7. mike5511

    mike5511 Road Train Member

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    The tech I use explained it to me, but I don't remember what all he said.....anything metal around your antenna will have a affect on it.
     
  8. mickeyrat

    mickeyrat Road Train Member

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    I now have what would seem a rather ignorant question, It is becuase I am ignorant of the answer, but on this 29LX I have calibrated according to instruction, SWR checks at one bar above 1 (guessing 1.2) now once I switch to S/RF function I get above three signal on the swr part of the meter when keying and have been heard on "radio checks" is this correct?

    what should I see on key under the S/RF setting?

    Ran the radio check feature and everything seems to pass.
     
  9. mike5511

    mike5511 Road Train Member

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    When it is in the S/RF mode it is measuring your incoming and out going signal. So you want to see it swing over to the red part of the meter and bounce forward when you modulate. Most stock out-of-the-box radios won't have much forward "swing", but the needle should still jump over to the right. at least at the edge of where the red starts when you key the mic. I would find a shop or a friend with a SWR meter and check my antenna if I were you. Then use the one built in the radio to check for changes. The meter in the radio is small and hard to read and they are not known for their accuracy. But it works good as a reference if you have checked out your system with a good meter or analyzer.
     
  10. BigBearNY

    BigBearNY Light Load Member

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    I likem usingb a dremel with a high speed cutoff wheel. It's fast, not as fast as bolt cutters, and leaves a smoother straighter cut.
     
  11. handlebar

    handlebar Heavy Load Member

    There's actually an adjustment pot inside the radio so that the meter can be set for whatever the tune-up manual says is about right for dead carrier; it can vary from radio to radio, and the pot in question affects *only* the meter, not your actual output. The meter should go up just a little when modulating, as your actual power only goes up by 50% when you're 100% modulated, and that meter is not linear in its calibration. I actually think it's easier to see at a glance when it rides in the white portion of the meter under deadkey and then deflects a little "north" when I speak into the mic.

    As to cutting antenna rods: I've got a stack of rods for different antennas and operating frequencies. I use them for testing. Once I put in one that reads close to being right, I fiddle a little with the length (up or down) until it's about right, then use a grinder to cut & round off the bottom end of the new whip and make final adjustments with that. Saves a lot of guesswork, and the cutting charts that come with new antennas seem to assume a perfect counterpoise area for the antenna's mount. I also secretly believe that the Easter Bunny and Santa Claus will visit my shop when I've been good.....
    73
     
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