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HF antennas with bad reputations.

Discussion in 'Antennas, Feedlines, Towers & Rotors' started by VK4FUQ, Sep 12, 2017.

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  1. N8CMQ

    N8CMQ Ham Member QRZ Page


    I also have no ground plane antennas, not even for VHF or UHF.
    I do have a discone for VHF and UHF, and I plan on having one for HF 40-6 meters in the future.
    For the time being tho, the ground mounted trap vertical is my only antenna, but that is because I don't have a rotable antenna, OTHERWISE, I would have a nice Yagi overhead. But since I don't climb too much any more, the care and maintenance of a Yagi is too much for me. A discone might be too, but I am going to try!
     
  2. NH7RO

    NH7RO Ham Member QRZ Page

    Cecil's easy to visualize analogy bears repeating; it is as brilliant as billions of photons beaming at point blank range into our eyes! I used to think that electrons did all the work making RF but found out that it is really a fully coordinated joint effort between the electrons and the photons. The electrons are the grunts and the photons are the Navy Seals in the general RF scheme of things---and I thank each and ever one of them for their valiant service. Without one or the other we would not have radio waves or light...

    Thanks again, Cecil for enlightening us in such a manner that even a simpleton like myself can readily understand.

    73,

    Jeff
     
    W5DXP likes this.
  3. N2EY

    N2EY Ham Member QRZ Page

    A Beverage is a traveling-wave antenna. It is vertically polarized. The explanations given are pretty good.

    The Beverage is named for its inventor (H. H. Beverage) and goes back to the very earliest days of radio. It can be used for transmitting, but the efficiency is terrible (10% or less).

    What makes a Beverage worthwhile is that it is very directional - in the direction of the wire - and it favors low-angle signals. This makes it a great DX antenna for the lower HF bands, because it doesn't hear signals or noise well in other directions, nor high-angle stuff. And all you need is a lot of room, a lot of wire, and some low supports. Plus a resistor for terminating, if desired.

    When Paul Godley went to Ardrossan moor in December 1921, to listen for North American amateurs on 200 meters, his antenna was a Beverage. He heard both spark and CW signals from US and Canadian amateurs - most notably 1BCG, a station set up for the express purpose.

    http://www.internetwork.com/radio/n1bcg/

    73 de Jim, N2EY
     
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  4. KF5FEI

    KF5FEI Ham Member QRZ Page

    I designed a 20m groundplane using a 20' crappie pole and a speaker tripod. Diddled with the feedpoint height on EZNEC to get the radials at a 45-degree angle and the feedpoint impedance as close to 50 ohms as possible. Built it, and had to trim only a few inches off the vertical radiator to get it resonant in the middle of the band. Worked great for PSK running 2.5 watts.
     
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  5. KJ4VTH

    KJ4VTH Ham Member QRZ Page

    A wet blanket has acquired bad reputation but is actually quite useful for small fires.
     
  6. NH7RO

    NH7RO Ham Member QRZ Page

    Good point; said wet blankets are especially useful for putting out fires that have been ignited by high voltages at the ends of wet noodle antennas in trees.
     
  7. KQ0J

    KQ0J XML Subscriber QRZ Page

    - End fed wire with the radiating wire entering the house.

    - Isotron

    - Comet CHA 250B

    - Terminated folded dipole

    - Ham Sticks etc used as a home antenna

    - Downspouts
     
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  8. NH7RO

    NH7RO Ham Member QRZ Page

    Finally! Someone responded with some really good answers!

    Don't forget J-poles, the Double Bazooka or ATAS 120...
     
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  9. K9STH

    K9STH Ham Member QRZ Page

    DT:

    Granted, a 40-meter dipole a wavelength above the Earth's surface will outperform a ground plane at the same height especially in the directions favored by the radiation pattern of the dipole.

    However, getting a 40-meter dipole over 60-feet above the Earth's surface is not possible for the vast majority of operators. Therefore, comparisons that really matter for most operators are for verticals / ground planes with the base (feed point) located at, or near, the surface of the Earth / r.f. ground and with low band antennas (160, 80, 60, 40, and 30-meter) located considerably less than a wavelength above the surface of the Earth / r.f. ground.

    Experiments in the AM broadcast band showed that 4-elevated, tuned, radials, 6-feet above the surface of the Earth, compare very favorably with the "standard" 120-buried radials. Those experiments were made at frequencies around 600 kHz, 1100 kHz, and 1500 kHz. In terms of wavelength, a radial elevated at 6-feet at 600 kHz equates to just 2-feet at 160-meters.

    In a practical sense, MF / HF radials at 2-feet above ground are not practical in many situations for a number of reasons including interference with humans, and animals, walking in the area. However, there are situations where such are possible and those exist in my situation. I have elevated radials for both my HyGain HyTower and for my full sized 40 / 30-meter vertical. Those radials run, at heights between 2-feet and 6-feet above the Earth's surface, along my wood stockade fence, along the retaining wall for my swimming pool, and along the slab / sides of my house. My HyTower works considerably better than when I had 48-buried radials. I had to go to the elevated radials when my swimming pool was installed a number of years ago.

    Glen, K9STH
     
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  10. WD0BCT

    WD0BCT Premium Subscriber QRZ Page

    Yes but it's better than a dry noodle!
     
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