Anybody know the Wind Load for JRMA0-680-10/11


#1

Technically not a B11 question, but I wasn’t sure where else I should post this…

I’ve asked the vendor (Jirous) if they can supply the wind load specs for the antenna in the subject, but have yet to hear anything back.

I have a 2 inch guyed pole (one is 6ft with 4 guys, the other 16 with 7 guys) onto which I want to mount two B11’s, but without the wind load for the antenna I cannot calculate if the structure is strong enough or needs to be replaced with a 3 pole commercial style tower.

Any guidance welcome – lee


#2

Personally, from using commercial dishes, the Jirous is a light duty style dish. I think they say 125 mph on the winds, but all the stress is put on the single “L” style mount in the rear. You could help out the wind load by seeing if you can run a small pipe/conduit from one side of the outer dish lip to another point (say a tower leg). This would help eliminate the twist on the rear mount.

A 2 inch pole will NOT be big enough, need at least a 4 inch Extra Heavy pole.

The fence contractor have a 4 inch diameter (or larger pole) that is called a HT-40 (Schedule 40).
We have used these going up water tanks to mount dishes on!

I would rather go with a guyed 3 leg tower, Rohn 55 or larger, and use a “Torsion guy mount” in the middle and at the top. Torsion mounts will stop the twist of the tower !

The tower would allow you to mount on one side (Putting a mount across 2 legs, with the dish mount in the center of the 2 legs on a 4 inch pole), then the stabilizer pole from the outer dish to the 3rd leg.

OR contact a structural engineer (or Rohn tower) and ask them what they would suggest? If you have to get a building permit to install this, you will need to have an engineer sign off on it anyway!


#3

Thanks Wanye,

I’m investigating that Rohn 55 and an artificial tree (unlikely) at the moment. No permit to mess with, but I’ll certainly be hiring a structural engineer, especially considering one location is on a 45 degree slope.

For those interested, the manufacturer did provide me with details:

@200km/h, 125mp/h
Front 707N, 159lbf
Back 792N, 178lbf
Side 71N, 16lbf