# EMT as antenna mast?



## InPhase277 (Feb 9, 2008)

I have a home made windmill with a 10' diameter supported from 1-1/2" EMT. I have three guy wires from the last 1/4 or so. It holds up amazingly well with a high load on it.

I don't see why you couldn't put a static load on it with some guy wires just to be sure.


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## Ultrarunner2017 (Oct 1, 2008)

InPhase277 said:


> I have a home made windmill with a 10' diameter supported from 1-1/2" EMT. I have three guy wires from the last 1/4 or so. It holds up amazingly well with a high load on it.
> 
> I don't see why you couldn't put a static load on it with some guy wires just to be sure.


A windmill! Do you generate your own electric, and if so, can you sell any of it back to POCO?

I can't guy my antenna install, since it's going on the wall of the house, next to an attic window, but considering that EMT is steel, just like the more expensive mast pipe sold by RS, and my antenna is minimal loading, I shouldn't have a problem.
I'm just not sure that the wall thickness on the EMT is comparable to the mast pipe, but I'm not going to sweat it (but I will be sweating the copper pipe; ha ha). It should be up there until the house comes down, or a neighbor complains<g>.

FW


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## InPhase277 (Feb 9, 2008)

My windmill is experimental, but I suppose that I could sell excess power back to the utility in the future. But not right now.

If you are concerned about the wall thickness, why not use a stick of rigid conduit?


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## Ultrarunner2017 (Oct 1, 2008)

InPhase277 said:


> My windmill is experimental, but I suppose that I could sell excess power back to the utility in the future. But not right now.
> 
> If you are concerned about the wall thickness, why not use a stick of rigid conduit?


I'll have to make that determination when I go to buy the stuff. Rigid is more expensive, so I don't want to use it unless I really think I'll need it.
I'm trying to keep the cost of this thing down too. That's why I'm building the J-pole out of copper instead of buying a Cushcraft Ringo Ranger, which would cost me over $100 (but it's a better antenna).
I just need something to get some use out of my 2 meter ham rig, and to double as a scanner antenna for listening to the railroads. Wouldn't need the outdoor antenna for the cops... they use high power repeaters. Trains don't.

On a slightly different subject:
What if I wasn't mounting the antenna to the house. What if it were on a tower in the back yard. Would I still need to run a continuous grounding conductor from the electrode at the base of the tower to the one at the SE?

FW


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## InPhase277 (Feb 9, 2008)

The EMT ought to be plenty sturdy for your antenna, especially mounted to the house, and a single 10' length. The grounding issue, I don't really know, and I no gotty me Code book, and me no wanny looky on the web.:whistling2:


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## kbsparky (Sep 11, 2008)

My TV antenna is supported with a section of 1¼" EMT. It's been on the end of my house for over 17 years, with no problems. And this is a rather large TV antenna, complete with a rotor assembly on the top of the mast.

As long as you have the EMT supported at the bottom, and a few feet up, it should be able to do the job.

As for grounding, I installed a pipe grounding clamp near the bottom, and ran a ground wire to a ground rod. There is also an interconnecting bonding wire that runs from there to my main ground at the electrical service.


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## theatretch85 (May 17, 2008)

One thing about the EMT is it will rust if you don't spray it with a protective paint. Get some rustoleum spray paint and paint it to match the house color. Or if you like, just get some gray spray paint, basically about what the EMT looks like un-painted. I don't believe the spray paint is enough to mess with the proper grounding properties, if you are concerned about it, spray a section of it and let it dry, then check it for continuity with a multimeter.


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## Speedy Petey (Feb 1, 2004)

I used 1" EMT for my two dual band (UHF/VHF) antennas and for my scanner antenna. It is almost the same size as those cheap painted gold antenna masts, and even stronger. For something big I'd go up to 1-1/4" like KB used.

For one I am using a gable end mount made out of deep Unistrut, one long piece and one short, and 1" strut straps.

Unless it is in an environment where it might get scratched EMT should not rust. It is coated/plated for corrosion resistance.


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## Ultrarunner2017 (Oct 1, 2008)

I am considering a coat of Rust-Oleum, but would probably install the ground clamp first, then mask it so as not to coat the terminal for the GC.
Luckily, my SE is on the same side as the antenna will be, so I only need to bring the GC down to its electrode. The system is bonded to the water pipe as well.

FW


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## theatretch85 (May 17, 2008)

I think the biggest areas I had issues with rust is where you drill the holes at in the conduit and typically the very ends of the conduit. Plus I can't imagine a piece of silvery/gray conduit blending in with the house very well, might look a little un-sightly to your neighbors.


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## Speedy Petey (Feb 1, 2004)

theatretch85 said:


> Plus I can't imagine a piece of silvery/gray conduit blending in with the house very well, might look a little un-sightly to your neighbors.


*#@% the neighbors!!

:laughing: JK :laughing:

The antennas are ugly enough, the mast is the last thing you'll notice.
I definitely do agree, any cuts or drills do need to be painted.


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## Ultrarunner2017 (Oct 1, 2008)

Maybe I'll paint the whole thing; antenna and mast a sky blue, or maybe even sky blue and cloud white, so it would blend in with the sky.
OTOH, maybe I should just add fake leaves, like they do for cell towers:laughing:

FW


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## kbsparky (Sep 11, 2008)

Even if it does eventually rust, it ain't worth the time and effort to rust-proof. A piece of EMT should last 20 years or more, and if it does rust out, it's cheaper to replace it than all this other muss and fuss, IMO.


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## Ultrarunner2017 (Oct 1, 2008)

kbsparky said:


> Even if it does eventually rust, it ain't worth the time and effort to rust-proof. A piece of EMT should last 20 years or more, and if it does rust out, it's cheaper to replace it than all this other muss and fuss, IMO.


Agreed.

FW


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## Ultrarunner2017 (Oct 1, 2008)

I went to HD today and priced out the EMT. I found that if I use 1-1/4", I have to buy the ground clamp for 1-1/4 to 2" and it is much more expensive than the one for 1/2" to 1" tube, so I think I'm going to use 1" EMT.

I was surprised at how heavy EMT is. The wall is a lot thicker than I had expected, so 1" will be fine.
BTW, the difference in cost of the clamps is about $2 for the 1/2" to 1", and nearly $7 for the 1-1/4" to 2". The two clamps aren't really comparable though, as the larger one was brass, or maybe bronze, and the smaller one was nickel plated steel.

I'm going to check out an electrical supply house before I buy anything from HD.

FW


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## Speedy Petey (Feb 1, 2004)

KE2KB said:


> I'm going to check out an electrical supply house before I buy anything from HD.


Good call. 
Stick with a bronze clamp, even the small one.


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## Ultrarunner2017 (Oct 1, 2008)

Speedy Petey said:


> Good call.
> Stick with a bronze clamp, even the small one.


Thanks for the advice. I guess the plated ones just rust out in a few years.
Considering the cost and labor involved with this project, I shouldn't cheap out on one of the more important parts.

FW


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## MALCO.New.York (May 29, 2009)

I once used a 10' stick of 1/2 EMT horizontally atop a light pole to suspend some plastic flags. Lasted 2 days 'til it bent.


Simple flags like these. 










http://tbn0.google.com/images?q=tbn...eamericanflagstore.com/library/MultiColor.gif


The wind has a lot of force.

3/4 " Black pipe will do the trick.


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## Speedy Petey (Feb 1, 2004)

MALCO.New.York said:


> I once used a 10' stick of 1/2 EMT horizontally atop a light pole to suspend some plastic flags. Lasted 2 days 'til it bent.
> .....
> 
> 3/4 " Black pipe will do the trick.


There is a HUGE difference between 1/2" EMT and 1" EMT with regard to strength. 

Also, 1" EMT is very close to the diameter of a specific antenna mast and even stronger.


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## Ultrarunner2017 (Oct 1, 2008)

I am going to go with 1-1/4" EMT. That's the standard size for antenna mast.
The only reason I thought of using 1" was that the ground clamp for 1" pipe was a lot cheaper than the one for 1-1/4", but I later realized that I was not looking at the same type of ground clamp. I need to use the bronze one, so the difference in cost isn't so much.

Judging by the thickness of the wall of 1-1/4" EMT, it is heavier than the steel mast pipe I used to buy from Radio Shack. Even those never bent, and I had some pretty heavy antenna on them, including a Wilson rotor (large one for amateur radio Yagi).

This antenna has a low wind loading. It's only a vertical 14ft high, with three small (20") radials at the bottom.

FW


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## c16mo (May 29, 2009)

I used an 1-1/4 inside a 1-1/2" emt to hold my Davis wireless weather station. This was about 15' above our rear deck. I never had a problem until a tornado came through and the mast bent - when the wind hit 190 MPH !


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## Ultrarunner2017 (Oct 1, 2008)

c16mo said:


> I used an 1-1/4 inside a 1-1/2" emt to hold my Davis wireless weather station. This was about 15' above our rear deck. I never had a problem until a tornado came through and the mast bent - when the wind hit 190 MPH !


The instrument actually remained operational up to 190mph?

FW


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## c16mo (May 29, 2009)

I didn't realize it for some time. The only thing usable after the tornado was the console so I bought a completely new system. When I eventually downloaded the old console to my laptop it had recorded 190 MPH winds. I actually suspect it may have recorded higher winds if the mast hadn't bent allowing the station to hit the roof (before the roof left). 




KE2KB said:


> The instrument actually remained operational up to 190mph?
> 
> FW


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