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Everything you know about dipole (calculators) is wrong ...

Discussion in 'Amateur Radio News' started by VK6FLAB, Oct 12, 2018.

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  1. KG5THG

    KG5THG Platinum Subscriber Platinum Subscriber QRZ Page

    They have grown up with "do not attempt" shown on every ad for a product and they have taken that to heart.
    WN1MB likes this.
  2. KM1H

    KM1H Ham Member QRZ Page

    That wont work for many because you forgot to include the necessary shortening as an inverted V. So for the next time use ~ -3%
    Then to take it a step further apply the ground effect shortening for antennas below 1/4 wave or so. That also changes the feed impedance so if the VSWR is worse than 1:1 an expensive antenna tuner may be needed.:rolleyes:

    Ham since 1955 and still building my own antennas from wires to multi element yagis.
    VK6APZ and WN1MB like this.
  3. KD5PUR

    KD5PUR Ham Member QRZ Page

    Most new cars don't come with spares anymore, mine did not. I had to buy one for it. At least it had a place to store it and a jack. He would have had fun with my old Plymouth, it had left hand threads on the left side wheels.
  4. KD5PUR

    KD5PUR Ham Member QRZ Page

    Worked for me. 468/7.2375/2= 32.33ft which got me a 1.3: swr across the band.
  5. WB4BLY

    WB4BLY Ham Member QRZ Page

    Also the height above ground and the orientation of the dipole elements as well as proximity to metallic objects affect the actual length for resonance at any frequency. Any calculator is only a quick math substitute to get you in the ball park and then you can fine tune for resonance at the desired operating frequency.
    Since I did not have a computer until 1980, I used a slide rule to calculate. I wonder how many people know what one is?

    VK6APZ, VK2WP, N1YR and 1 other person like this.
  6. KM1H

    KM1H Ham Member QRZ Page

    I still have my K&E from the 60's but havent used it since hand held scientific calculators became affordable. Used various bench versions at work.
    WN1MB likes this.
  7. AA5CT

    AA5CT Ham Member QRZ Page

    FOR the computer generation, it works like this

    256, 128, 64, 32, 16 ... POWERS of 2, right (2^8, 2^7 etc.)?

    The above are the approximate 1/2 wavelengths for -

    160 - 80 - 40 - 20 - 10 meters respectively.

    (for other bands, freqs, consult the formula for a starting point ...)
    VK6APZ, VK2WP and WN1MB like this.
  8. AC7DD

    AC7DD Premium Subscriber QRZ Page

    I saw what you did there.
  9. WA6VVC

    WA6VVC Ham Member QRZ Page

    What's even crazier is buying a simple dipole and paying 90 bucks for it. Coax extra, connectors... add more $$.
    K8AI, KR3DX, W5TTP and 2 others like this.
  10. N6QIC

    N6QIC Premium Subscriber QRZ Page

    This is how I did the calculations for my antenna in 2014: $39.00 + 7.5 percent sales tax + $4.00 gas + 1 hour of time = my new 10 thru 40 meter antenna from HRO. :)

    KH2RU and KA9JLM like this.

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