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Recommendation requested...tripod mount
Posted: Sun Jun 22, 2008 9:40 pm
by kfd29
Looking at mounting a DB224 rooftop. The easiest option would be to use the existing tripod, which is bolted and welded to the steel rooftop. Any opinions on this? Can't find any data on the tripod as far as weight loading, etc. Would a heavy duty tripod hold a 20 foot antenna without a problem in this situation? I'm thinking it may be fine, possibly with some guy lines as well.
Re: Recommendation requested...tripod mount
Posted: Sun Jun 29, 2008 10:22 am
by psapengineer
Without a picture it's hard to guess.
If it's really bolted (not screwed) to structural members (thick steel "eye" beams (darn font can't make an I )) and if it's really welded to structure (again thick beams), and the tripod's designed support pipe is 2.375" OD, I might not be scared to death about using it.
I hope I've left you with the impression that in my opinion I'd be scared to use a tripod mount for a DB224.
In our applications on structures (like our newest fire station in the county) we use 2.375" OD Galv Pipe and weld it to true structural members, not just purlins, at a point where the structrural members cross (typically in three planes) and have sufficent area to support the torque. The support pipe then has flashing (like a vent flashing) as it penetrates the roof. We don't use guy wires. The support pipe is not in any way tied to the roofing materials.
I hope this helps. Regards, Bob
Re: Recommendation requested...tripod mount
Posted: Sun Jun 29, 2008 4:45 pm
by Will
I remember working on this project in Jan 06. The tripod is indeed welded to the roof support structure.
The tripod is a / simmular to: Rohn Products R-TR160
I doubt it will support the heavy DB224 antenna.
Re: Recommendation requested...tripod mount
Posted: Sun Jun 29, 2008 7:58 pm
by tvsjr
Why would you want a DB224 on a tripod rooftop mount? 224s are meant to be hanging from towers, being used by repeaters. You can achieve similar performance using a much-less-heavy fiberglass stick. Why the need for the 224?
Re: Recommendation requested...tripod mount
Posted: Mon Jun 30, 2008 1:43 am
by Will
tvsjr wrote:Why would you want a DB224 on a tripod rooftop mount? 224s are meant to be hanging from towers, being used by repeaters. You can achieve similar performance using a much-less-heavy fiberglass stick. Why the need for the 224?
Well, let's see:
The tripod is on top of a multistory building, supporting the antenna for the repeater............................................ in the middle of the coverage area.
The DB224 antenna has more gain!
Re: Recommendation requested...tripod mount
Posted: Mon Jun 30, 2008 5:44 am
by tvsjr
Will wrote:Well, let's see:
The tripod is on top of a multistory building, supporting the antenna for the repeater............................................ in the middle of the coverage area.
The DB224 antenna has more gain!
Hmm... an RFS220, or a DB616, or the competitors from Andrew, Sinc, etc. will provide the same amount of gain, and do it with significantly less wind loading and lateral thrust.