How high can I go?

Discussion in 'Antennas, Feedlines, Towers & Rotors' started by MUSTANGMARTY, Jul 26, 2020.

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  1. MUSTANGMARTY

    MUSTANGMARTY QRZ Member

    I’ve got four pieces of 2” square tubing that are 24ft long each. They are galvanized and 11 gauge. With proper guying, how high can I go? It will have a couple 4ft x 2ft panel vhf/uhf antennas for now along with an HD-73 rotator. I plan on putting a small radio antenna up there too once I decide what to get radio-wise. I have a 20 ft utility pole ten feet from the house. I also have 2-3/8” pipe fencing right up against that utility pole. What’s the best way to get as much height as I can with or without using the utility pole. Also, what size and strand count guy wire should I use. I’m out in the country in Central Texas, so storms do come around from time to time.
     
    Last edited: Jul 26, 2020
  2. WB2WIK

    WB2WIK Platinum Subscriber Platinum Subscriber QRZ Page

    How will you splice the 24' sections together, if you use more than one?
     
  3. MUSTANGMARTY

    MUSTANGMARTY QRZ Member

    3ft pieces of 2-1/2” x 1/4” thick square tubing, like a tight outer sleeve/splice either welded or bolted together. Not sure about that yet.
     
  4. WB2WIK

    WB2WIK Platinum Subscriber Platinum Subscriber QRZ Page

    Sounds pretty heavy duty.

    If there's a way to lift that weight safely, I'd think going to 48' and guying at two levels (24' and 48') would likely work fine.

    Of course, if a permit is required for installation, the grantor would likely need to see construction plans and calculations to verify it could be done safely and meet the various municipal or county requirements for structures.
     
  5. W4HWD

    W4HWD Platinum Subscriber Platinum Subscriber QRZ Page

    Why not buy a push-up mast? They come is many lengths and loads, most are light enough to be UPS shippable, and they're very inexpensive. They also come with complete instructions so you won't be getting installation advice online from people you don't know - people who won't be there when your hastily cobbled-together pipes collapse.

    As for that utility pole: Is there an actual utility on it, like power and an area light? If so, placing an antenna on it is not only a massive safety hazard, but is also subjects the antenna to removal by the local power company. If it's a bare pole you placed there then have at it.

    Properly safe installations will provide years of service and won't present a safety hazard - either during or after installation.
     
    AJ5J and AI3V like this.
  6. WB2WIK

    WB2WIK Platinum Subscriber Platinum Subscriber QRZ Page

    If his 24' tubing is as described, it's much heavier-duty than the Rohn H30-40-50 push-up masts. Much. He said 11 ga galvanized steel. The Rohns are way lighter than that (both in wall thickness and in weight), they're 16 ga at most.

    The Rohn push-up masts require guying at each section, so a 50-footer (which is actually about 45 ft. when extended, due to section overlap) requires five sets of guys. Two 24' sections of 11 ga would only require two sets of guys.

    11 ga. is very heavy stuff and when made into tubing, very strong stuff. Sounds like these were intended to be structural supports for something heavy.
     
  7. AI3V

    AI3V Ham Member QRZ Page

    Sell the tubing to somebody building a utility trailer and buy yourself a engineered radio mast.

    Rege
     
    KI5AAI likes this.
  8. W1TRY

    W1TRY XML Subscriber QRZ Page

    What about making a tripod with 3 of the 4 pieces and putting the 4th section up through the center? Sounds like you have access to additional metal and welding capability.
    Or, parallel 2 sections vertically with a third piece in the middle that could be pivoted to allow you to raise and lower by tilting at the midpoint.
    Yes, I know, these ideas can be ripped to pieces for a variety of reasons, but we're still in the planning stages here...
     
    AJ5J likes this.
  9. W4HWD

    W4HWD Platinum Subscriber Platinum Subscriber QRZ Page

    The OP did mention guying, and each mast comes with specifics for guying and what to use. As for the pipe being thicker, I'd imagine any gauge of pipe would be unacceptable for a large yagi; a properly guyed push-up mast could support a V/UHF yagi with the rotator specified by the OP. If the OP plans on putting up anything larger he'd be better served with a properly installed tower; pipes quickly exceed their usefulness against wind loading regardless of wall thickness. Plus, as you asked earlier, how does OP plan to connect a bunch of straight pipe? Not a problem with a push-up mast.

    I'm just saying that if it was me, instead of haphazardly slapping a bunch of pipes together, I'd call DXE and order a push-up mast sized for the application. When it comes to things tall and vertical, DIY is sometimes the least desirable option.
     
    KI5AAI, AI3V and AJ5J like this.
  10. WB2WIK

    WB2WIK Platinum Subscriber Platinum Subscriber QRZ Page

    I guess it depends on antenna installation experience.

    The "upper section" of the tubular extendable towers such as those currently sold by U.S. Tower, which are clearly engineered specifically for beam antennas/rotators etc. use an 11 ga. 2" square tubing as the "upper extendable section" of their multi-kilobuck towers. They have all engineering specifications and wind load ratings per latest standards on line.

    If the square tubing discussed by the OP is high-carbon steel designed for structural support (sounds like it is, but would be nice to know), it would be a lot stronger than a typical Rohn push-up mast. He already described how to splice it using even larger tubing and a close fit. Since the tubing discussed is already galvanized, I'd have to assume the splice would be via drilled holes and through bolts, because I wouldn't want to try welding to the galvanize.
     

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