very short retractable tower

Discussion in 'Antennas, Feedlines, Towers & Rotors' started by KU7I, Aug 11, 2017.

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  1. KU7I

    KU7I Ham Member QRZ Page

    Looking for input on a retractable antenna tower for a full size 20 meter yagi. I am looking for a crank up/retractable unit that will go down to about 10 feet and extend to 30 feet. Are there such animals out there in current production? Electric winch is essential. Thank you for any input. Lane Ku7i
     
  2. KM3F

    KM3F Ham Member QRZ Page

    Sure, its called an extension ladder.
    Much cheaper.
    We do it on field days and at other locations with up to 50 feet on a trailer.
    A little effort with a crank winch and a base your there.
    Good luck..
     
    NH7RO likes this.
  3. KV6O

    KV6O Premium Subscriber QRZ Page

    A pneumatic mast is probably what you're looking for to get that low. Not sure if any of the tower manufactures make something that small, and MA-40 is about 40 feet extended, 21 feet lowered.
     
  4. NH7RO

    NH7RO Ham Member QRZ Page

    An extension ladder securely mounted and a winch from Harbor Freight should fill the bill nicely; just don't forget to print out a 20% off coupon before heading over to HF.

    No matter what size Yagi you'll be putting up it'll still require at least 3 guy ropes, too.

    73, Jeff
     
  5. WB3BEL

    WB3BEL Ham Member QRZ Page

    Depends on what you call a full size 20m Yagi.... If 2 Ele maybe there are stock solutions depending on your wind zone and regulatory requirements... 5 Ele or bigger is a different beast. Most of these smallish towers are not really designed for lots of wind load. You can always get something custom made but I think you are looking for something simpler.

    http://www.tashtowers.com/docs/MW33-01.pdf

    Force 12 made some LPT towers that were even more lightweight and I think they were taken over by Innovantennas, but not sure if they are making the LPT series still. It is probably too lightweight for permanent use although might suffice for a trailer tower in temporary service in a not too windy location.
     
  6. WB2WIK

    WB2WIK Premium Subscriber QRZ Page

    Tashtowers (used to be "Tri-Ex" years ago) model MW-33 is 33' when extended and 13' when retracted.

    It's strong and you can add a motor drive to it if you wish.

    I've installed these before, they're very good and come with the "base;" you supply the concrete!
     
  7. W0AAT

    W0AAT XML Subscriber QRZ Page

    US Tower has 2 models that crank down to 12 feet, I have the heavy duty TMM433hd. Nice tower! LOT of concrete!!!
     
  8. WA7PRC

    WA7PRC Ham Member QRZ Page

    The datasheet for the Tashjian MW33 shows it uses a Fulton K1550 "brake winch" (a manual winch). The OP wants an electric-powered winch. A right-angle slow speed drill can be adapted to drive the winch. I got the idea from Rick N6RK (link) to drive the K2550 winches on my 72' tall crankup/tiltover tower. I didn't want to mess around, and bought the gnarliest drill I could find, a Milwaukee "Super Hawg":
    [​IMG][​IMG]
    (click for bigly images)

    I use it to drive both of my crankup and tiltover winches. A smaller/lighter tower could use a smaller drill. The bonus is, I can also drill yuuge holes in almost anything! :D

    Bryan WA7PRC
     
    NH7RO likes this.
  9. WB2WIK

    WB2WIK Premium Subscriber QRZ Page

    Yep, that works.

    The Tashtower and U.S. Tower versions both come with a manual winch, but in both cases a motorized drive can be installed as an option. When that is installed, it allows for "remote" (push a button in the shack) operation if desired.

    I'm not wild about using remote operation for tower extension (if a kid is nearby and happens to stick a finger, hand or arm in the webbing, he can lose it) but if the property is completely protected so nobody can be near the tower it can be pretty safe.

    If "noise" is a concern, a motor drive on either of these short towers may be a problem, as they can be noisy going up and down. A heavy-duty pneumatic mast like those used on news gathering vans is much quieter; in fact, you can't even hear them operate, and they extend and retract very quickly. But the HD ones that could support a 20m beam are also very expensive, and you need an air compressor (somewhere) to keep a tank of compressed air filled in order to run it.
     
  10. K2CAJ

    K2CAJ XML Subscriber QRZ Page

    Okay, now this got me thinking.

    I'm building a tilt-up, push-up metal+fiberglass mast in my backyard, next to my detached garage. This is 2 nested metal pipes from Home Depot for the first 19 feet, and the inner pipe is wide enough to hold the fat end of my 40' Spiderpole. In theory this could give me a very tall mast, but my goal is to have more strength at the same height: I'm going to use the bottom half of the Spiderpole to get a 40' total height with a 1-inch diameter at the top.

    Anyway, that's the plan. I now realize that instead of building the 19' nesting metal mast I could use an extension ladder, which I can likewise secure to the concrete footing and the side of the garage. I can then securely mount a pipe to the top ladder segment to chuck the base of the Spiderpole. The ladder already has a mechanism to raise and lower it from the ground. Plus, it's a ladder: I can justify buying it for non-radio uses.

    Does this sound like a foolish idea? I know it will look a little dorkier, although this is for a temporary antenna setup, nothing that I plan to leave up.
     

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