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

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

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  1. WN1MB

    WN1MB XML Subscriber QRZ Page

    I'm literally laughing out loud. My first car was a 1963 Plymouth Valiant. Being completely unaware of those left hand threads (and being 16 years old and full of pee, vinegar, and testosterone), the first time I had to remove one of those wheels resulted snapping off two lugs before I got a clue. heh.
    W1TRY, KC1DR and WR2E like this.
  2. KA9JLM

    KA9JLM Ham Member QRZ Page

    What is Free Space ? :rolleyes:
    N6QIC likes this.
  3. N6QIC

    N6QIC Premium Subscriber QRZ Page

    Easy question,

    Free space is, the place you park your car for free. :)
  4. AA5CT

    AA5CT Ham Member QRZ Page

    That space which is not claimed by The Federation, the Klingons or Vulcans?
    K8AI and N6QIC like this.
  5. AE5GT

    AE5GT Ham Member QRZ Page

    The ARRL does http://www.arrl.org/shop/L-C-F-and-Single-Layer-Coil-Winding-Calculator/
    N6ITE likes this.
  6. W5DXP

    W5DXP Ham Member QRZ Page

    Everything you (plural) know about dipole calculators is wrong? Does that plural you apply to everyone except you?:)

    The speed of light in a vacuum is constant. Anything besides a vacuum slows light down. The fraction of slowing is called the velocity factor. The velocity factor of RG-213 is 0.66, i.e. 2/3 the speed of light in a vacuum. The velocity of light in an insulated wire is a function of the type and thickness of the insulation. Physicists have developed materials that slow the speed of light down to a virtual crawl.
    AE5GT and N6ITE like this.
  7. N6YFM

    N6YFM XML Subscriber QRZ Page

    Calculator? Really?
    All I need is my VISA Card and the phone number of DX Engineering...
    N6QIC likes this.
  8. VK6APZ

    VK6APZ Premium Subscriber QRZ Page

    Don't forget to add the Balun.

    Attached Files:

    N6ITE likes this.
  9. SA6CKE

    SA6CKE Premium Subscriber QRZ Page

    Yet another factor that also influences the real antenna size compared to the theoretical is the distance to and reflectivity of the ground plane and other surrounding objects. Some of this is why the weather influences your communication abilities.

    So imagine you have a dipole on top of a gravel and sand ridge and you set it up and tune it when the weather has been dry for several weeks, then it rains and you suddenly get a bad SWR. This because the ground plane is actually well below the ground surface and instead a lot further away below your feet when you stand on the ground in dry weather while when the ground is wet the ground plane is right under your feet.

    The formal theory looks easy, then the reality arrives and messes up everything.
    N6ITE likes this.
  10. KC9YGN

    KC9YGN Platinum Subscriber Platinum Subscriber QRZ Page

    My car doesn't have a spare tire or a jack. Equipped with "run-flat" tires, or so they claim.

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