[TowerTalk] Sigma 280s

[Mark Beckwith]

> Has anyone erected a Sigma 280S 80 meter beam ...
> A friend of mine is considering the installation
> of such a beam antenna on a Rohn 25 at the
> 80 foot level.

My seat-of-the-pants says this is too much antenna for Rohn 25.  Also, 
assuming DXing is the object, 80 feet height for a yagi is pretty low in 
terms of wavelength - it would be like trying to work DX with a 20 meter 
beam at 20 feet - possible but far from optimal.  If DX were the object, 
your friend could save a heck of a lot of effort and money by using the 80 
foot tower as the central support for a 4-square made of wire.  That would 
get a whole lot more of your friend's signal into the DX station's ears, for 
less money.

Here's a photo of a 2-element Sigma that got killed by ice.

http://www.n5ot.com/sigma80.jpg

The manufacturer said the element truss cabling was not done properly which 
I guess means the manufacturer thinks it would have withstood the storm if 
it had been done properly.  Or something.

73 - Mark, N5OT