[TowerTalk] Tower loading
K7LXC@aol.com
K7LXC@aol.com
Fri, 17 Dec 1999 14:01:46 EST
In a message dated 99-12-17 08:06:54 EST, boerkamp@nortelnetworks.com writes:
> Hello everyone.....I have a 48ft heavy duty delhi tower (rated for 9 sq ft)
> with a
> 20ft mast (10ft sticking up out of the tower) , tailtwister, 2 bearings
and
> a TH7
> tribander at about 55ft... i am just wondering if I were to add guy wires
to
> the
> tower (its a self support), can I add more loading to it?? ie. 2 el 40
> I dont know how conservative the rating of the tower is.....I wish to
> improve
> my antenna situation on 40m (presently an inv-v which doesnt work too well)
The Delhi tower is what is the Rohn BX series down here in the States.
On the plus side, Delhi does provide the big straight sections (BX8, BX7,
etc.) that Rohn does not so you can wind up with a medium-duty tower.
On the negative side, it's still BX-type and has the same inherent
limitations.
I know for a fact that many VE hams have VERY aggressive loads on
bigger Delhi towers and that sometimes they are guyed. Are either of these
practices sanctioned by the manufacturer? Probably not. Are they nonetheless
reliable? They seem to be.
You didn't say which Delhi sections you have (or what your local
windspeed conditions are) but if they are the smaller ones, I'd be real
hesitant about doing it. OTOH, a single element Force 12 40M dipole might not
severely upset the applecart. Would I personally do it? Probably, knowing
that sometime in the future it was going to fail (harmlessly) on my property.
If you want to improve your 40M performance, using the K3LR/N7ML
switching, bottom-pulled back sloping dipole system seems to work very well
and will fit on your tower.
Cheers, Steve K7LXC
Tower Tech
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