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  • Schedule 40 as TV Antenna Mast

    I'm new here and need some help. I'm using a 1 1/4" ID sched40 pipe as a TV antenna mast. I intend to slide a 1 1/4" OD thin gauge pipe into it to allow lowering and raising the antenna from atop the roof without taking it loose from the gable. I used a Lenox hole saw to ream off the weld from inside the larger pipe and now the smaller pipe fits, but it's tight. If I can take another 1/16" off it'll work great. What tools are available to grind or ream more from inside the schedule40 pipe? I need to go down 12 feet.

  • #2
    Re: Schedule 40 as TV Antenna Mast

    Two questions:

    Are you asking to take off 1/16" throughout the wall of a 12' long pipe?

    Are you a retired engineer?

    J.C.

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    • #3
      Re: Schedule 40 as TV Antenna Mast

      The pipe is 24' long. I will run a bolt thru both at the 21' line so three feet will remain in the larger pipe at all times for stability. No I'm not an engineer, just a farmer.

      Comment


      • #4
        Re: Schedule 40 as TV Antenna Mast

        ... and yes I want to remove 1/16" all the way down 12'.

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        • #5
          Re: Schedule 40 as TV Antenna Mast

          Gotcha'. I think I understand. You want one pipe inside the other with the internal one adjustable.

          I can't think of anything that will give you 1/16" removal of the internal diameter of the 1-1/4" schedule 40 pipe for 12 feet. Every kind of bit that long seems like it would get off track and destroy the pipe.

          You could use the 1-1/4" schedule 40 pipe as the internal slide pipe.

          Then upsize the external pipe to a size that will allow the internal pipe to slide freely. 1-1/2" schedule 40 maybe. Then put a schedule 40 pressure cap on top of the larger pipe, then drill it to match the internal slide pipe size. In my brain that would make it more stable. But I've also been exposed to alot of glue.

          PVC can "break down" under longterm sunlight exposure. Heavier schedule 40 should last a long time though. Or you can paint it.

          Hope this helps some.

          J.C.

          Comment


          • #6
            Re: Schedule 40 as TV Antenna Mast

            1'' sch 40 gal pipe fits very nicely into 1.25'' sch 40 gal pipe. try that combination and you'll be good to go

            rick.
            phoebe it is

            Comment


            • #7
              Re: Schedule 40 as TV Antenna Mast

              If I'm reading correctly, you're talking iron water pipe, no?

              Ditch the pipe, it's waaaay too much work.

              Call your local steel supplier and ask if he has telescoping tubing. The mechanical properties of nearly any grade of steel mechanical tubing will be far better than the properties of water pipe.

              Consider square tubing. For a given dimension, square is stiffer and stronger than round. And you can get telescoping tubing in square, too.

              Corrosion will be a problem. Lube everything up with waterproof lubricant, then you gotta come up with a way to keep moisture out, lube in. I can't quite picture your design, but the moisture business sounds like it might not be all that easy.

              Next issue is wind loading. Check the code. You will need to do some simple aerodynamic calculations to get the load and then compute the stress in the pipe. Your local planning department can recommend an engineer that can do this for you. The large antenna masts I designed for Mil use were rated for 100 knot wind. Yours is not mil spec but there is a wind load requirement and it's not trivial. Best to check. The thing will become a spear if it breaks.

              As a minimum, if you don't want to have it engineered (not recommended - do at your own risk!!), at least rig a chain up as a safety so if it breaks it won't go flying and impale someone. You're talking about pretty big heavy pieces of steel here, plenty enough to be dangerous.

              Comment


              • #8
                Re: Schedule 40 as TV Antenna Mast

                electrical ridgid conduit is seamless and the ridgid comes in 10' lengths. plus it's already galvanized and should last a lifetime in the exterior climate with no further work.

                problem is it's only 10' and not the 12' you want. get the 1.25'' and 1'' ridgid sch 40 electrical conduit. the regular plumbing sch. 40 is not typically seamless as you know.

                i would think that guy wire at the top and middle sections tied off at 3 opposing angles will properly support the extended height.

                then again you can always get cable or satellite

                rick.
                phoebe it is

                Comment


                • #9
                  Re: Schedule 40 as TV Antenna Mast

                  I would suggest to try to find a different slide pipe or one to slide into,
                  to ream out the 1/16"of an inch would be a real challenge, not impossible as I think one could make a cutter, but unless one is willing to go to machine shop to have the cutter made and get a carbide lath bit to put into the cutter and that would cost you more than the different pipe, to my knowledge no cutter exist off the shelf, (how I would try to make a cutter, get a section of shaft that will fit the inside of the pipe, drill a hole about 2/3 to one end that will accept a lath bit, drill and tap a cross hole that one can use a set screw to lock the lath bit in the shaft, drill and tap the short end of the shaft to accept a long shaft, (do not know if 7/16 sucker rod would work or not, but 1/2 shaft I think would, set the lathe bit so a 1/32"+ extends out of the shaft, use a 1/2" heavy duty drill to slowly drill it out), but I do not know how effective it would work. but that is how I would try it. since you reamed it out smooth with the Hole saw you should be about to get the tolerance of the shaft fairly close if machined, but by the time one would get it made you could buy a different pipe,

                  part of the problem is you remove the galvanizing if any left and if it is a tight fit it will rust up fast making removal nearly impossible,

                  http://www.use-enco.com/CGI/INSRIT?P...&PARTPG=INLMK3
                  if you click on catatalog page and go to 163 one can buy the indivigle bits,

                  do a search for tool bits,
                  http://www1.mscdirect.com/cgi/nnsrhm

                  the 1 inch Rick suggested is probably your best bet,

                  or going to an auction and just buying a old TV tower, Digital TV sucks doest"t.
                  Last edited by BHD; 09-02-2009, 10:30 AM.
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                  • #10
                    Re: Schedule 40 as TV Antenna Mast

                    Direct TV or dish network.

                    Comment


                    • #11
                      Re: Schedule 40 as TV Antenna Mast

                      ....i would think if you want to use plastic all you have to do, if you're worried about sunlight breaking down the plastic, is get a hold of electrical plastic pipe conduit. it comes in many sizes and is uv safe. jmo

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                      • #12
                        Re: Schedule 40 as TV Antenna Mast

                        At this moment, this fella comes to mind.
                        Attached Files
                        sigpic

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                        • #13
                          Re: Schedule 40 as TV Antenna Mast

                          Analog t.v. is dead, so what's the antenna for? Are you communicating with the Mother Ship?
                          (The Low Spark of Steel-Toed Boys)

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                          • #14
                            Re: Schedule 40 as TV Antenna Mast

                            If your determined a hard guided hone like a Sun will do it in time. They guide on the ID but it will take a while and the drive rod will have to be made. Better to change to a different pipe set or best to buy a mast

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                            • #15
                              Re: Schedule 40 as TV Antenna Mast

                              You should ask this Q over here.

                              http://forums.qrz.com/index.php

                              There you will find all you want to know about constructing antenna masts, tower erection (no Viarga needed) , and just about anything related to antennas.
                              ---------------
                              Light is faster than sound. That's why some people seem really bright until you hear them speak.
                              ---------------
                              “If I had my life to live over again, I'd be a plumber.” - Albert Einstein
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                              "Its a table saw.... Do you know where your fingers are?"
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                              sigpic http://www.helmetstohardhats.com/

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