Thoughts on using an AV 640 vertical horizontal

Discussion in 'Antennas, Feedlines, Towers & Rotors' started by K9XR, Jul 4, 2021.

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  1. K9XR

    K9XR Ham Member QRZ Page

    Years ago I bought a Hy-Gain AV-640 vertical hoping the HOA rules would relax. Well as we all know that never happened. Now with tge Sunspots starting to show some life, I am thinking about HF again.

    This antenna is one of those that has a Capacitive Cap Hat system for a counterpoise. Because of that I am thinking of putting it up in my attic Horizontally. Has anybody tried this? Thoughts? Thanks
     
  2. KI8DJ

    KI8DJ Ham Member QRZ Page

    Should work but will not have the low angle gain like it would mounted vertically. Also will pick up noise from devices in your house and interfere with some. Tuning will be altered by metal in your attic to if there is any. In my opinion you would be better served by and end fed wire outside the house something like jacketed 26 gauge painted grey feed by a 9 to 1 or 49 to 1 unun. This would be nearly invisible from a distance.
     
  3. WB2WIK

    WB2WIK Platinum Subscriber Platinum Subscriber QRZ Page

    I doubt that would work well, for a few reasons; one that springs to mind is the radials aren't a capacity hat, they're shortened radials which can work because the antenna is voltage-fed at high Z, so there's little current there. But aren't they also about 7 feet across (which would mean 7' vertically if installed laying down)? That would require a pretty tall attic.

    There's also high voltage at the tips of the radials when transmitting. Those are normally kept well above "reaching" level so nobody can touch them, making for a safe installation. But if the radial tips touch anything other than just "air" (wood, or really anything) that can cause a spark which may ignite nearby materials and that wouldn't be fun at all.

    I think the idea to ditch the vertical (or sell it) and just install an "invisible wire" antenna outdoors is a better one.
     
    AK5B likes this.
  4. K9XR

    K9XR Ham Member QRZ Page

    My idea was to hang it off of the ridge beam and if need be rotate the antenna to give the radials "maximum air". I am not sure how long the radials are because I have never had the antenna together. Any outside wire is out of the question because my wife is the head HOA Nazi. I do presently have a 275ft. =/- long wire looped around my attic and running down 2 floors and then to the basement where the shack is. About half of that wire is wound on a 3"piece of PVC. I feed it with a Palomar PT3000 tuner and for some reason the only place it seems effective is on 160 meters.

    I used to have one of those Spider Dipoles which was basically 2 mobile antennas put together, but I gave it to my son hoping it would get him on the air. That worked OK but of course it was very narrow banded on 40. I mostly only operate CW so it wasn't a huge problem. I was thinking this AV-640 would be more effective mostly because of its size (over 25 ft). I have one (actually 2) of those old AEA magnetic loops. I have used it in the garage on a tripod, but never in the attic. That is another possibility, but it only covers 10 - 30 MHZ. I thought about a Steppir Dipole, but don't really want to spend that kind of money. Oh well, back to the drawing board.
     
  5. US7IGN

    US7IGN Ham Member QRZ Page

    Thoughts on using an AV 640 vertical horizontal

    It is quite possible, only you need second one and the dipole of them must be placed at a height of at least 20 meters. And don't forget about the rotary device.

    A friend of mine has such an antenna and it works very well on the roof. I am surprised that such a small antenna is prohibited in your place.

    P.S. If my wife were the head HOA, in my yard there would be a huge mast with antennas for all bands at the expense of HOA for its own good. And the HOA would also pay me every month for service it...
     
    AK5B and K9XR like this.
  6. KC3GHK

    KC3GHK XML Subscriber QRZ Page

    I use an inverted L feed under my deck, 9 to 1 unun, radials hidden in the yard and antenna wire up my deck tree over the top of it and two pines and partially down the far tree! Works great but requires radials that are slit into yard at night!
    Or try a dipole in your attic and use electric fence stand offs to keep it from touching anything and get creative with how to route the ends! Put link connectors on it to use say on 40 and 20! Just remember it will pick up noise in the house so be creative with rf chokes!
     
  7. RW4HFN

    RW4HFN Ham Member QRZ Page

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