AV 640 Hygain base 72 inch whips

Discussion in 'Antennas, Feedlines, Towers & Rotors' started by KE9HS, Oct 20, 2020.

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  1. KE9HS

    KE9HS Ham Member QRZ Page

    I am thinking about placing a AV 640 near the house attached to a 12 foot pipe above ground set in concrete. Due to a few trees near by, this would be an good location in the lot that the house sits on. The location is away from the trees, but a couple of the whips which bend at the base will be about 2 feet at the end from the house metal rain gutter. Will this cause a lot of headaches in tuning the Antenna? Or might the 50 foot metal rain gutter might help it (wishful thinking).
  2. KB1CKT

    KB1CKT Ham Member QRZ Page

    I'd be more worried about the antenna next to the house and "hearing" all your electronic gizmos. I'd rather be closer to the trees!

    I wouldn't think 2 feet from the radials would be problematic.

    A 12 foot tall pipe? Two questions come to mind--how stiff is this going to be (think antenna swaying in the breeze), and are you going to stand on a ladder to do antenna work (tall step ladder).

    Are you going to guy the antenna?
  3. KE9HS

    KE9HS Ham Member QRZ Page

    I was not very clear on the support of the 12 foot pipe. I would have 2 metal posts set in concrete with about 4 feet above ground. The 12 foot tall pipe would go between (a gap big enough to fit) the metal posts held with large lag bolts in a way you can walk the 12 foot pipe with the antenna up from the ground. I have not bought anything right now, just formulating a plan.
  4. KB1CKT

    KB1CKT Ham Member QRZ Page

    Ah, I think I see. Like a mini-tower, using the house for support at the top? but otherwise next to the house?
  5. KE9HS

    KE9HS Ham Member QRZ Page

    The antenna would be on the corner of the deck about 12 feet away from the house over hang, see picture. The wood deck on a ground slop is 3 feet higher than the ground level and at the same level as the house. The bottom of the antenna with the whips (connected to the pipe) would be away from the house at the corner deck and the whips when installed to the antenna would be near the same elevation of the lower part of the roof that has the rain gutter. The whips would not be above the rain gutter but near the side. I think the picture might make it clearer. The neighbors house has the same roof slope.

    Yes, I would definitely run it closer to the trees, but there are power lines on the other side. So the deck location avoids the worse. Power lines and Cables 013.JPG
  6. KB1CKT

    KB1CKT Ham Member QRZ Page

    Hmm, I am not sure. But I think those radial-less antennas tend to be tricky to tune in general (or so I've read), so putting next to a gutter may cause some interaction. Worse tuning than in the normal case? I'm guessing no worse.
  7. WB2WIK

    WB2WIK Platinum Subscriber Platinum Subscriber QRZ Page

    The AV-640 is really easy to "tune," I've used those.

    The "whips" are radials. There is high voltage at the tips of those when you transmit, so you wouldn't want them to be low enough that anyone can touch them. Whether the rain gutter will have any impact, I have no idea, but my first guess is "not much."

    However, at 12' above ground, while you'll clear the edge of the roof okay, the feedpoint will be below the peak of the roof. I'd go for "higher," so the entire antenna is above the roof peak, if possible. With a stout supporting system embedded in a concrete foundation, I'd think you could go for a 20' mast if it's a strong mast.

    I usually use 6061-T6 2" OD aluminum hollowbar, which comes in 24' lengths and is available from all aluminum suppliers. It's very strong but not heavy. With the AV-640 on top, tilting it up from a secure hinging system as you describe is a one-man job...whole thing would weigh about 30 lbs, and even at the worst tilt angle it wouldn't feel particularly heavy to me.

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