Mounting a HF vertical antenna on the building rooftop

Discussion in 'Antennas, Feedlines, Towers & Rotors' started by OK8EI, Jun 3, 2021.

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  1. AK5B

    AK5B Ham Member QRZ Page

    No, not at all.

    I was merely stating that the difference between a shortened vertical ( that has been optimized as much as humanly possible) and a standard full-size one was not as great as it would seem--- until you pretty much shot that theory of Sevick's down.

    If I had more antennas at my disposal I would gladly include as many horizontal dipoles, Yagis, Moxons and Lazy Hs as I could in my antenna farm---I have nothing against horizontal antennas unless they are too low to the ground for working dx consistently---if I had the supports for some high enough to do so...

    As a matter of fact, one of my current projects is a tri-band Moxon (10-15-20) that I plan to put on a telescoping mast that I can raise for periods of time when I plan to operate. I'm sure once that is completed I will prefer it over any other verticals I haven going on here---no question.

    I am currently working on two verticals, a 10-20m 5-band fan vertical elevated about ten feet above the ground---I'm in the tuning stage now and once finished will install the elevated 40m vertical (wire inside the Spiderpole Mini 33' tall FG pole and with the two radials you modeled for me a while back) mounted near the top of a big wooden beam. Then the work on the Moxon will also be completed. I need to fashion a hub mounting bracket and string some wire between the spreaders---and then I'll really have something to compare on 10-15-20m between the vertical and the horizontal beam.

    While I have only been listening occasionally on the fan vertical I have discovered that my neighborhood is delightfully RFI quiet and I look forward to becoming active chasing dx after a long spell of interruptions from moving house and such here.

    I have always believed that one can never have too many antennas and I will also string up a horizontal wire or two here at some point, too.

    EDIT: we are experiencing a major downpour and thunderstorm right now so will post this while I still have power and an internet connection---and respond to other points later.

    73,

    Jeff
     
    Last edited: Jun 4, 2021
  2. W9XMT

    W9XMT Ham Member QRZ Page

    Time (again) for some fact-checking on this subject. Please refer to the graphic below.

    WA7ARK: How are you able to scientifically deny the Physics of this reality?

    [​IMG]
     
  3. WA7ARK

    WA7ARK Ham Member QRZ Page

    Dirt simple. No signals (except for RFI) arrive from an elevation of 4degrees. 99% of signals arrive from elevations ~25degrees and higher.
     
    Last edited: Jun 4, 2021
    SWL37632 likes this.
  4. W9XMT

    W9XMT Ham Member QRZ Page

    Your unproven opinion will be a surprise to the 100-yr-old AM broadcast industry, as the greatest amount of the nighttime skywave coverage areas of such 50 kW 24/7 stations use and depend upon skip angles much less than 25° (see the entries outlined by red rectangles on the graphic below).

    [​IMG]
     
    Last edited: Jun 4, 2021
  5. W1VT

    W1VT Ham Member QRZ Page

  6. K8JD

    K8JD Ham Member QRZ Page

    I hate to come in late on this subject , but I would consider using a commonly available 5 or 6 band, trap vertical antenna, the radial requirment for above ground radials is minimal, with just 2 or 3 for each band you are serious about using. The ground mounted vertical with buried radials often is suggested, but not roof mounted. Been-there-done-that both ways. (I worked more DX with 40 and 20 M roof mounted GP verticals !!)
    I have read articles about AM broadcasters moving from the 180 buried radials to six ELEVATED above ground radials. And getting all the same field strengths.
    I agree you also should consider getting on V/UHF bands with that high location for antennas.
     
    M0AGP and AK5B like this.

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