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35' PVC Antenna Mast/Tower Ideas

Discussion in 'Antennas, Feedlines, Towers & Rotors' started by KD8EZP, Feb 22, 2011.

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  1. KD8EZP

    KD8EZP Ham Member QRZ Page

    Does anybody have any thoughts on building a 35' mast useing 4" PVC pipe?

    I was thinking of mounting the 10' x 4" pvc between two wooden 8' 4x4's that would be half mounted in a concrete base. The 4" pipe would be fixed with two bolts to that when one bolt is removed the mast could swing down. A portion of the bottom of the 4" pipe could be filled with concrete for ballast. On top of the 4" pipe would be 10' x 3" PVC pipe and on top of that 10'x 2", then on top of that 10' x 1.5". Of course they would sleeve into one another for a certain amount and acheiving aproximately 35'.

    Does this sound feasable?

    Dave
     
  2. W4AFB

    W4AFB Guest

    A 40ft Rohn push up pole would be a better bet and safer.
     
  3. N3JPB

    N3JPB Ham Member QRZ Page

    Dave,

    What you are describing is actually quite a popular method of installing a vertical antenna, as an example:

    http://verticaldipoles.tripod.com/MountingSystems.html

    What you are describing gives you a stable platform for housing your antenna. Now, what are you planning to put into this "empty shell"? Your radiating elements could be made of wire or made of copper pipe. Are you going to make the antenna a dipole (as in the cited example - then the center feed line must be perpendicular to the radiating elements) or as an end fed radiator with a field of buried radials? Are you planning to use a choke/balun?

    Good luck with your project.

    Regards, John (N3JPB)
     
  4. G0GQK

    G0GQK Ham Member QRZ Page

    What you have to consider is the weight of plastic tubing when it is moved from a horizontal position to a vertical. The idea is sound but the plastic material could be a problem as there is very little rigidity. What do you intend to do with this vertical tube ? Support a dipole or as a vertical radiator ?

    The usual method is to taper a vertical to lessen the weight as it is raised, you would be surprised at how heavy things become. If it is to be a vertical why not consider an extending fibreglass pole and extend the lower section by the addition of timber or aluminium tubing which will fit over the outside of the fibreglass.

    Or use a smaller diameter plastic tube and strengthen it by inserting wood.

    G0GQK
     
  5. K9STH

    K9STH Ham Member QRZ Page

    PVC is NOT rated as a structural material. When the weather gets cold, which I do believe it does in Michigan ( :rolleyes: ), and the winter wind blows, there is a VERY good chance of the PVC failing and down comes the antenna.

    Glen, K9STH
     
  6. WX7G

    WX7G Ham Member QRZ Page

    PVC is a terrible structural material. Wood on the other hand is very nice. And aluminum is even better.
     
  7. N8WH

    N8WH Ham Member QRZ Page

    sIR.i HAVE A 37FT. PVC MAST THAT HAS BEEN UP FOR 6 YEARS. i USED SCHEDULE 80 PVC PIPE AND REDUCING BELL TYPE COUPLINGS(HEAVY ON THE GLUE) ALSO I INSTALLED FOUR NYLON ROPE GUYS APROX 18 INCHES BELOW THE ANTENNA. I USED 4" TO 3" TO 2" TO 1.5". THE BELL TYPE REDUCING COUPLINGS ARE MUCH BETTER THAN THE STRAIGHT COUPLINGS.

    BILL
     
  8. WA4OTD

    WA4OTD XML Subscriber QRZ Page

    You can get a kit of 12 four foot fiberglass poles for about $20 that are meant to be an antenna support. They do require guy wires. You can get these on ebay or at most hamfests.
     
  9. KD8EZP

    KD8EZP Ham Member QRZ Page

    Wow, I didn't expect so many helpfull comments. The mast would be used to support an OCF Dipole. Also perhaps a 2 meter vert (later). Well from the comments it sounds like it might be worth having a go. The scedule 80 (or 120) pipe would be best. I'm not sure how available that is compared to just running down to lowes or something. Thanks all.

    N8WH - Where did you get the 'Bell Type Reducing Couplings'?.
     
  10. W4AFB

    W4AFB Guest

    Find a push up pole. You'll be much happier and have a safer structure.
     
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