“Best” Multi-band HF Antenna ?

Discussion in 'Antennas, Feedlines, Towers & Rotors' started by K2POP, Jul 26, 2011.

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  1. EI4GMB

    EI4GMB Ham Member QRZ Page

    The thing that bothers me most about 1/4 wave verticals is that they don't display any gain. Perhaps you could explain?

    Fred EI4GMB
     
  2. K2POP

    K2POP Ham Member QRZ Page

    Thanks Glen. Can you mention any names? Which verticals might be worth putting up? I do not have room for a full-size Hy-Tower.

    73, Richard
     
  3. WB2WIK

    WB2WIK Platinum Subscriber Platinum Subscriber QRZ Page

    Of course they don't since they're not directional. The only way to achieve gain is to change the radiation pattern.

    A horizontal dipole over "real earth" always has substantial gain, in two directions. It has negative gain in other directions.

    Verticals can work fine, but in my experience, better for transmitting than for receiving; reason is, they can be very efficient emitters but very noisy receptors. I often transmit on my 40m vertical and hear stations calling me who are in the noise, so I switch to a different antenna to hear them. It's all part of the fun!
     
  4. EI4GMB

    EI4GMB Ham Member QRZ Page

    Thanks for that explanation Steve. It sure helps. :)

    73,

    Fred EI4GMB
     
    Last edited: Jul 27, 2011
  5. KJ3N

    KJ3N Ham Member QRZ Page

    Elevated or ground mounted?
     
  6. K7KBN

    K7KBN Ham Member QRZ Page

    Define "best". Everyone has his own idea of what the "best" antenna is. YOU need to define it for yourself, and then build it.
     
  7. WB2WIK

    WB2WIK Platinum Subscriber Platinum Subscriber QRZ Page

    And if you build it, they will come!
     

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  8. K9STH

    K9STH Platinum Subscriber Platinum Subscriber QRZ Page

    GMB:

    Phased verticals work a lot like a yagi. They take away signal in certain directions and add it to the signal in the preferred direction. My phased verticals are 35 feet apart which is about the maximum that I can get in my backyard, this is a quarter-wavelength. Then the phasing network puts them 90 degrees phasing. The resulting pattern in a cardioid ("heart shaped") with a theoretical gain of 4.5 dB in the desired direction and about 20 dB null "off the back". This pattern gives a side gain of about 3 dB. I have the phasing set up so that I can reverse the pattern, that is, the maximum gain direction and the null direction can be reversed.

    Due to the layout of my yard, the maximum gain is either on Japan or on South America. But, when in either phase I still have 3 dB gain into Europe/Africa and 3 dB gain into Asia/Oceania. Due to the physical nature (basically being on top of a hill), the effective gain, due to an even lower angle of radiation, is even more.

    Since I live in a suburban location, there is no way to effectively measure the actual pattern and gain/attenuation. However, based on comparisons with either vertical operating by itself and with the phasing in each direction, the effective gain is definitely more than the theoretical gain in free space. The "S" meters on the receivers that I used are accurately calibrated for S-9 = 50 microvolts, each "S" unit is very close to 6 dB, and the "dB over" readings are very accurate. I do have an accurately calibrated receiver that is actually designed to read field strengths. Unfortunately, it covers 375 MHz to 1000 MHz! As such, it is of no use on HF!

    Glen, K9STH
     
  9. EI4GMB

    EI4GMB Ham Member QRZ Page

    Glen, I'm getting more used to this idea of phased verticals the more I hear about them. They certainly have their benefits. I sure have learned something new again today. Many thanks.:)

    Best Regards

    Fred EI4GMB
     
  10. AK4GA

    AK4GA Ham Member QRZ Page

    AI4JI OCF Dipole
     
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