black iron pipe for a mast?

[iMONITOR]

Schedule 80 PVC, although twice the thickness of schedule 40, will initially be stronger. But again, unless it’s dipped or coated with something, the sunlight will degrade the oils in the plastic and cause it to become brittle over time. There’s a reason why it’s for direct burial only. I’ve even seen specialized plastic pipes that are rated for exterior applications above ground become weathered and brittle over time. Some people have luck with it and some don’t. YMMV.

I've always heard that here on RR in the past. However I just discovered this:

How Long Will PVC Pipe Last in the Sun

How Long Will PVC Pipe Last in the Sun | Home Inspection Insider

PVC pipe is lightweight and very durable, but I was curious about how it holds up in the sun as I heard PEX would fail…

homeinspectioninsider.com

Maybe it's been improved?

 

[clbsquared]

I've always heard that here on RR in the past. However I just discovered this:

How Long Will PVC Pipe Last in the Sun

How Long Will PVC Pipe Last in the Sun | Home Inspection Insider

PVC pipe is lightweight and very durable, but I was curious about how it holds up in the sun as I heard PEX would fail…

homeinspectioninsider.com

Maybe it's been improved?

I suppose it has. Every time I try to use or re-use pvc pipe that’s been sitting in the sun for a while, it just shatters. Maybe it was older than the new stuff coming out. Still though, I’m not sure how 2 20 foot sections of pvc standing straight up without any support, while trying to support an antenna, will work. Unless you guy it to something.

 

[KB4MSZ]

I have used PVC in a number of Yagi antennas in which both the boom and the elements are PVC. My oldest Yagi is almost 4 years old now. I guess I should take it down and give it a good look-over.

Not sure how well PVC would work as a vertical mast holding an antenna with any sizeable wind load, that is a different stress factor.

 

[Duckford]

Are there any cheaper alternatives to the high end Rohn that work well? I'm interested in doing things right.

I don't have a high income. I own nice things because I manage my money and costs well.

 

[wwhitby]

I've looked at that Rohn H50 several times.

I have as well, but the truck freight charge has kept me from buying one.

I have used PVC in a number of Yagi antennas in which both the boom and the elements are PVC. My oldest Yagi is almost 4 years old now. I guess I should take it down and give it a good look-over.

Not sure how well PVC would work as a vertical mast holding an antenna with any sizeable wind load, that is a different stress factor.

I built a twin lead J-pole back in June 2011 and encased it in a piece of PVC pipe. Its been out in the sun since that date. I checked on three weeks ago, and its still fine.

Also, there's a lot of PVC piping used in swimming pools and the pipes connecting the pump, tank, et al, are above ground and out in the sun. I haven't heard of any failures with the PVC pipes.

 

[Firekite]

truck freight charge has kept me from buying one.

Easy Up has versions shortened to fit on UPS trucks available on Amazon or various other online retailers, maybe locally.

I haven't heard of any failures with the PVC pipes.

I have. Most of them are buried, of course, but for those exposed they get brittle, losing their plasticity. It’s not enough to make them explode from 40 PSI of water, necessarily, so they can generally be in service until they get stepped on and crack or a fitting repair needs to be made and trying to cut them causes them to break like an old bone instead of cut cleanly. It’s part (not all) of the reason they’re advised against for shop air.

For antenna elements and such, I don’t think it’s a big deal, as they’re not generally stressed all that much. For a mast, well, your mileage may vary.

 

[chief21]

A good alternative for a vertical mast is one or more sections of top rail for chain link fencing.
These sections are typically 10.5 feet long, of a larger diameter than typical TV mast sections, with one end swaged to accept another section, and galvanized. These top rail sections can be found at most big-box home stores at reasonable prices. In my experience, they do not bend easily and are very durable.

 

[O-B-1]

Black iron 1" pipe is very flexible and the couplings are a weak point. I put up three sections for an SWL wire antenna and it should have been guyed, for sure. the couplings weakness may lie in the fact that they have very little length of thread/pipe in the coupler.

 

[ClemsonSCJ]

Black iron 1" pipe is very flexible and the couplings are a weak point. I put up three sections for an SWL wire antenna and it should have been guyed, for sure. the couplings weakness may lie in the fact that they have very little length of thread/pipe in the coupler.

I ended up doing rigid conduit (I think 2-1/4”? I can’t remember) for one and fence top rail for the other. I did three 10ft sections for both. I put them in 2 separate roof apexes and used apex brackets to support them a little under halfway up (there’s about 17ft above the brackets on both). To mount to the ground I used a floor bracket for the rigid tubing and screwed it to a 2ft 6”x6” ground rated post that I buried to where the too just barely shows out of the ground. Did the same for the fence top rail, except I just used a paddle bit to drill out a hole for the tapered end to shove down into. The rigid conduit is holding a diamond x300 for my main radio and the fence top rail is holding a diamond x200 for my digipeater/iGate. Both are about dead on 30ft at the base of the antennas.

In hindsight, for your standard omnidirectional antenna the fence top rail is plenty enough. Anything heavier the rigid may be better but for these antennas, I can’t really see either one moving significantly in the wind, and certainly not one more than the other.

I also painted both a mix of green and brown camo paint from Lowes for the bottom 2/3 and a “glacier white” color (somewhat of a grayish white) and the brown/green blends in perfect with the trees behind our house no matter the time of year (foliage or bare) and the glacier white was a better compromise than trying to do straight blue for the sky. It blends decently well in blue skies but blends really well in overcast skies or blue skies with clouds.

 

[W3DMV]

If your looking for something to pick up locally, go to a electrical supply
house and get some "Rigid Aluminum Conduit. Good and strong and the
weight is much lower. I have several made of 2.5-2.0 and 1.5" which you
can telescope inside each other and pin with bolts. (2Ft overlap). I can walk
up a 26Ft pole with a modest size antennas mounted at the top. It's also
practical to mount the mast vertical while telescoped down, and after
securing it to the bracket, you can slide the pipe sections upward and
secure with the bolts...

 

[Duckford]

I've got a pile of black iron pipe, but I never got it up before the snow hit. Now with three feet of snow on the ground, I think I'll give it a try once the warm weather hits....

But a good thread.

 

[jeepsandradios]

Assaid black iron will break at the splice. even Galvinized will snap there. For under 10' its ideal, over 10' there are many options.

 

[StoliRaz]

Not the same but I have my weather station on a 5 ft length of black pipe, I spray bombed it 3x with satin black rustolium. After 1 year the threads that show on the bottom of the pipe have surface rust showing but the rest is looking great. I might relocate it to a taller mast off my house this summer. For such a short length if I had to do it over again I'd probably just use PVC.

 

[ClemsonSCJ]

Assaid black iron will break at the splice. even Galvinized will snap there. For under 10' its ideal, over 10' there are many options.

With a heavy antenna or something that creates a lot of wind resistance, MAYBE. For a 10ft omni like my Diamond X300, this rigid conduit will likely last a life time. The threaded joint did not appear to be a weak spot at all.

 

[robertwbob]

interesting. i got 40 feet black pipe beside my house guyed well and a gable mount. its held an a 99 for years ,now sports a gp9 . i got sleeves that slide over the pipe n weld them. as for rust its not showing much rust but inviroment comes into play here too.
use what you can afford and work up money for better.
simple reason i used that pipe,well dad n i put it up there in 1973 for tv antenna . and last time i looked i got about 10 joints of that 1.50" diameter pipe. if it goes bad more pipe will go up. your milage might vary from mine

 

[kg5nii]

I did something similar about 10 years ago. I bought three sections of 1-3/8 in x 10 ft. 6 in. 17-Gauge Galvanized Top Rail from Home Depot. These are tapered at one end so they lock together. I wet the ground below the apex of the roof on our single story home. I then used a fence post hammer to drive it about 5 ft into the ground. I attached the next 10 ft section to it which brought to top just above the apex of the roof. I used a eave mount bracket to attach to pole to the roof apex. I then mounted a 2M/440 J-Pole antenna and coax to the top of the third section and slid it over the two stacked poles. This gave me a J-Pole antenna on top of a 25 ft mast with no guy wires. It has withstood many 60 MPH+ windstorms over the years and still works great.

Though your post is a year old, it is very useful. Easy to find materials, and has been time tested. This solves a technical problem in a very cost effective way. Thank you.

 

[Deeptow]

I use 2 inch rigid. Its galvanized. Black pipe, in time, will rust.

Black iron will indeed rust, and must at least be painted. Also put a cap on the top or water will come in, generate rust in the middle of the pipe, and said rust will then drip onto the surface below your pipe. If it's your roof, it will look bad in short order.

I have used HEAVY DUTY conduit atop a 10 ft. tripod on my roof in the past. On top of that was a homebrew J-pole. I also capped the conduit with a tight fitting piece of wood dowel sealed with RTV. It withstood years of Cape Cod weather. Eventually, a new roof forced me to take down the tripod. I replaced it with a "plastic tower", using a number of sections of fiberglass camo poles stood off the side of the house with Solid Signal standoffs and a Diamond X30 on the top. So far so good after 2 years of sun, rain, ice, snow and high winds.