[TowerTalk] Commercial Towers

[Tower2sell@aol.com]

In a message dated Fri, 1 Sep 2000  2:25:22 PM Eastern Daylight Time, JRH <jrh@lemoorenet.com> writes:

<< 
My curiosity got the best of me the other day and I stopped and had
a look at this commercial tower site. They had 20 hardline cables
as big as my arm running up next to one of the tower legs. Seems to
me they should have distributed the weight of those cables amoung
the legs of the tower but I see none of these sites do that. Each
leg of the tower was round in shape and had what looked like a small
copper wire to ground. 
>>

The answer is that weight doesn't matter, its the projected area. By grouping the lines together you can get a smaller projected area. The typical weight of the lines is about one pount per foot... almost nothing for a comercial tower to hold up. The size of lines can sometimes depend on the antenna and the frequency. I'm not an RF engineer, but I have noted that for microwave dishes, the higher the frequency - the larger the cable. Maybe someone else can shead some insite on this. 

The wind area shielding of the lines is major design aspect and it involves consideration of iceing and wind load. Personnally, I perfer to shield the line back to back on the tower face. Inside the tower would be the best place and out on the leg the worst place.

Not all engineers think a like, as you can see.

As far as the grounding is concerned...haven't a clue. Some people are religious about it and others want the code minimum. You can find instalations across the spctrum. If it works and it is safe, what else do you need. 



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