In many situations, you CAN properly (and sturdily) join two lengths of PVC pipe! (What ever you do, do NOT use the couplers normally sold to join two pieces of PVC pipe, they are NOT mechanically strong, and just plain won't work in this situation.) You need a 3-4' length of pipe of (usually) one size LARGER than your mast portions, and split it lengthwise. (A table saw used judiciously comes in handy, but you may be able to get away with using a hacksaw. Be CAREFUL, either way.) There should be a tight fit once the pipe is split. Using (at least 3-4) hose clamps to close the split pipe,. insert both pieces of mast into this coupling equally, and tighten the hose clamps! Works and lasts as long as the PVC masts last, which is 20+ years (and counting.) Of course, guying IS required.
What schedule/diameter of PVC are you using? In other words, how high can you go with what diameter? Now ya got me thinking
I find this interesting, I'm thinking of having a small yagi or quad for 6M at the top of my tower but dont want the rotor up there Thinking of 1-1/2" abs since it will probably bend just enough to get it into the tower, then make a splice where needed I have a thrust bearing for the top and would intend to use some metal pipe to connect that to the antenna. same at the ground for the rotor
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I wound not suggest going too high, but of course, YMMV. I am using 2 lengths of 1.5" schedule 40 pipe, and it certainly will last, since it is also used for (long-term) outdoor irrigation. The coupling is one size bigger pipe. IF you slice through ONE side of the 3-4' "coupler" (where a table saw is easy) lengthwise, it is just enough to join the 1.5" pipe, and then held securely with hose clamps. So I get about 18-20' from 2 sections of PVC pipe. If you use larger size pipe, you can probably go a bit higher, but you will STILL need guy wires, and a stable base to hold the bottom. For my 18+' mast, a 3' TV type tripod serves to anchor the bottom. (Since I rent, and don't currently own, I can't really do anything "permanent," but this "temporary" arrangement originally lasted 20 years, and now, after rebuilding the wire portion(s) I will be using the same mast sections and tripod.) I hope to get it all back up this week, and I'll try to provide a picture or two.
I experimented with PVC masts many years ago with some success. (I worked in a PVC pipe factory, hi hi.) I put a rubber/cork/wooden stopper in both ends of each section and filled it with dry sand. Greatly improved the rigidity (and the weight!) Just food for thought.
That would certainly add weight! Since I'm using a relatively low mast and guyed, rigidity isn't a significant concern.
I've recently found that some steel T posts, the heavy kind used for cattle/horse fencing exactly fits in 1.5" schedule 40 pipe as well as the schedule 40 conduit pipe. But the PVC is lots cheaper. I plan on using it for some deer fencing around my corn field which is not real big. I doubt deer can jump 10'. But the wife insists I paint it black. I can deal with that. It's certainly cheaper than a 12' 4x4 treated lumber.
Be mindful of which sand you buy at the store: there's dry sand and playground sand--the latter is courser and retains moisture more than (dry) sand.
We mounted out 2m/70cm up high as possible on our chimney using pvc and have had no issues at all. The Diamond X300A is 10ft tall the mounting base for the mast is secured to 3/4 marine grade plywood using 3.5" heavy duty muffler clamps. The mast itself is 3" schedule 80 CPVC 36" for the lower section to a schedule 80 CPVC union the going up 10 feet with schedule 80 3" to a 3" to 2" schedule 80 reducing bushing to 24 inches of 2" schedule 80 CPVC with a cap. The antenna mounts perfectly with the factory saddle clamp mount with zero issues. The tip of the antenna is approximately 41 feet straight up. It reaches out well and our SWR is 1:1 on 2m and 1.5:1 on 70 cm. We use LMR400 from the antenna right to the radio.
That's great. But "why?" A length of extruded aluminum tubing with .125" wall is slightly lighter in weight, has better rigidity, and probably doesn't cost more. So, PVC can certainly work if you go to the lengths you did...but "why?"
Might mention a big advantage of a conductive mast (aluminum or galvanized steel) is you can attach the "antenna ground" wire to the bottom of the mast.. With a PVC (or any non-conducting) mast, you'd have to attach that to the antenna itself, which may be inconvenient and will create a more inductive path for lightning.
