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Thread: Large masts for wire antenna support

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  1. #1
    Join Date
    Sep 2008
    Location
    Northwest AR
    Posts
    295

    Default Large masts for wire antenna support

    I'm interested in building a large, permanently installed mast a minimum of 60' in height at the apex.

    It would be used as the center support of one or perhaps two wire antennas. For the sake of discussion, let's say the antennas both have a balun to make them about as heavy as a wire antenna gets.

    I know a number of you have done something similar. What are your suggestions for ensuring long term viability, guying, and any other insight you may be able to share?

    Thanks in advance!
    73,

    Andrew
    ---------------
    VP of Northwest Arkansas' The Noise Blankers Amateur Radio Club, WR5P
    One of the authors of Ham Hijinks, a ham radio-based humor and satire site
    Follow me on Twitter: www.twitter.com/K5PO - (@reply me and I'll follow you back)
    Check out our video, which won 2nd Place in the ARRL Video Contest!

  2. #2
    Join Date
    Oct 2003
    Location
    Middle Georgia USA
    Posts
    7,234

    Default

    At 20-40 feet a mast is practical. At 60 feet, it is really difficult to build a strong mast. Even when guyed.

    For example in 70 MPH wind a self supporting 80 meter tapered tubing vertical with nothing at the top, needs to be something like 5 inch aluminum or larger at the base, and have a few yards of concrete in good soil.

    I think at 60 feet you are talking telephone pole or guyed steel tower as the most economical, if you want reasonable real wind ratings.

  3. #3
    Join Date
    Sep 2008
    Location
    Northwest AR
    Posts
    295

    Default

    Thanks Tom. That's what I was afraid to hear, but since you've got more antennas than Clear Channel Communications, I guess I better take your word for it!
    73,

    Andrew
    ---------------
    VP of Northwest Arkansas' The Noise Blankers Amateur Radio Club, WR5P
    One of the authors of Ham Hijinks, a ham radio-based humor and satire site
    Follow me on Twitter: www.twitter.com/K5PO - (@reply me and I'll follow you back)
    Check out our video, which won 2nd Place in the ARRL Video Contest!

  4. #4

    Default

    A guyed mast should work. Rohn makes an H50 (actual height 44.6 ft). Guyed, those will support wire antennas. Rohn used to make an H60, but no longer, and those are difficult to find used. Some people have homebrewed an added section to an H50 but I don't know how that worked out. I have considered that but have not tied it.

    Jerry, K4SAV

  5. #5

    Default

    I'd think if it's only holding wire antennas and not beams an aluminum tower could be a good choice.

    I normally don't like aluminum towers and really don't want to climb them. (Beams can make them twist apart, too.) But if you use pulleys and ropes on the tower, you'd really never have to climb it to hoist up wire antennas as often as you want. Might be an easier solution.

  6. #6
    Join Date
    Oct 2005
    Location
    Del Rio, Texas
    Posts
    3,495

    Default

    From the school of hard knocks - buy a quality pulley after inspecting pulleys carefully. Out of convenience I bought a pulley from one place because the other one didn't open until later in the day. I didn't pay attention to the slack in the housing that later allowed my new rope to get pinched by the pulley rendering it useless resulting in lowering and raising my mast AFTER reinstalling a better pulley. I've used pulleys for many years never had an issue before, lesson learned.

  7. #7
    Join Date
    Apr 2001
    Location
    Shropshire. England.
    Posts
    15,164

    Default

    Without being rude, your problem would be getting it up !

  8. #8
    Join Date
    Oct 2005
    Location
    Brighton UK locator IO90XU
    Posts
    1,987

    Default

    For GOOD pulleys, look at stuff in yacht chandlers.
    Pete M3KXZ

    ANTENNA

    Think of it K3LR and 6Y1V.

    Best contest stations in the world?

    What do they use?

    Antennas.

    Proud Antenna User

  9. #9
    Join Date
    Oct 2003
    Location
    Middle Georgia USA
    Posts
    7,234

    Default

    Quote Originally Posted by K4SAV View Post
    A guyed mast should work. Rohn makes an H50 (actual height 44.6 ft). Guyed, those will support wire antennas. Rohn used to make an H60, but no longer, and those are difficult to find used. Some people have homebrewed an added section to an H50 but I don't know how that worked out. I have considered that but have not tied it.

    Jerry, K4SAV
    I agree at 40 feet or so, a guyed mast is practical......but he said a minimum of 60 feet. That's a problem if someone wants it to handle any real wind. At that height I'd just get a cheap used TV tower and guy it. Besides, his picture looks a bit like the Jim Morrison, the lizard king.

  10. #10

    Default

    Quote Originally Posted by M3KXZ View Post
    For GOOD pulleys, look at stuff in yacht chandlers.
    Good idea, but anything that has the word "marine" on it costs more for some reason.

    I remember working to design chargers for a battery company in Pennsylvania who provided L-A storage batteries to many OEMs including Sears, Montgomery Ward, et al. Those companies don't make any batteries, they just have them private labeled by actual battery manufacturers, and this was a big one.

    I asked the chief engineer one day what the difference between a car battery and a marine battery was. He said the marine battery had a polypropylene rope attached to it (so you could hoist it out) and the case had the image of an anchor molded into it. I said, "No really, what's the design difference?"

    "I just told you."

    The marine batteries sold for 50% more. That's a really expensive piece of rope.

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