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CB Install, SWR Meter Question

Discussion in 'Communication & Navigation' started by MDH33, Aug 24, 2006.

  1. MDH33

    MDH33

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    I recently installed a CB and adjustable antenna in my FJ40 and I picked up a Radio shack SWR meter (Ebay) to check SWR. I have a question about how to use the SWR. It came with no instructions and the only instructions I could find online don't seem to jive with the meter I have. :confused:

    The instructions I found say to attach the meter and set the CB to channel 1,19,40 then with the meter switched to FWD, hit the transmit button and adjust the needle to the "Set" position. My Radioshack meter does not have a "Set" position... nor does it have FWD or REF as the instructions state. It has the switch for SWR and FS and the adjustment knob. The meter reads 1 - 3 and has a red zone and an infinity symbol. So, I'm wondering what I'm suppossed to be setting it to before switching to the SWR setting and taking the reading.

    If anyone has an idea what I'm suppossed to be doing with this, please respond.

    Thanks!! :D
     
  2. mr_manny

    mr_manny

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  3. slickrock

    slickrock

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    That is how I figured out how to use mine. You need to adjust the needle until it just hits the red then release transmission. Then flip the switch and see where the needle pegs. It should be really low numbers and make sure it isn't too high.
     
  4. MDH33

    MDH33

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    So the "Set" point is just at the beginning of the red zone?
     
  5. BMAN

    BMAN

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    The set point might also be the CAL point on your unit. It means Calibrate.
     
  6. BMAN

    BMAN

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    Assuming that you have
    http://www.radioshack.com/sm-cb-high-frequency-ham-power-swr-meter--pi-2036239.html

    1 You will tune your radio to Ch 1
    2 Set center switch to Cal
    3 Key mic then turn Knob until the needle hits the CAL mark on the far right side of meter.
    4 Release key.
    5 Switch center switch to SWR and key mic,
    record reading.

    6 Tune radio to ch 40.
    Repeat steps 2-5

    "If the SWR on channel 1 is greater than that on channel 40, then your antenna is considered to be TOO SHORT and INCREASING the physical height will correct this situation. Inversely if the SWR on 1 is lower than that on channel 40, your antenna is considered TOO LONG and DECREASING the physical height will correct this situation.

    If measurements are below 2.0 to 1 on both channels 1 and 40, it generally isn't necessary to make any adjustment unless you want to fine tune the system to balance the SWR at both ends of the frequency band. However, keep in mind that if the SWR, regardless of the reading, is the same on channels 1 and 40-adjustment to the antenna will generally have a negative effect."
     
  7. 1990 LJ78

    1990 LJ78

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    Well said BMAN..
    I confirm your explanation..
    Regards
     
  8. MDH33

    MDH33

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    Thanks for that explanation. That is the meter I have and it does have "cal" on the far end of the red zone. I tried calibrating as you described and the needle never comes out of the red zone after switching from adjust to swr. I checked my coax and ground and it's set up as it should be as far as I can tell. Any ideas?
     
  9. BMAN

    BMAN

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    Disconnect your coax from the back of the radio and check for continuity between the center pin and outer sheath. If you have continuity that's bad.

    Do not use your radio until this is solved (your SWR's being in check that is).

    One thing at a time and we'll get it nailed down for ya.
     
  10. BMAN

    BMAN

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  11. REZARF

    REZARF

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    Thanks for the write up here, just tuned up my antenna in about 5 minutes with the help of this thread.

    Thanks Bman, this was a great guide!

    Rezarf <><
     
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