[TowerTalk] Cost effectivel Tower height

[Dick Dievendorff]

Andreas wrote:

>> - self supporting, no guy wires

Andreas, I started my planning at my current location with that same
requirement: no guy wires. 

I had previously owned a US Towers 89' crankup, which worked well for many
years. But I was changing antennas and the old tower's wind load capacity
wasn't enough for the antennas I wanted for my new "bluff" location. It gets
breezy around here.  But a 250' drop off to sea water to the East made the
site especially attractive to me.  HFTA and some Dayton presentations by
W6NL helped me understand how attractive it is.

I selected the antennas, then started engineering calculations for various
self-supporting towers, including Trylon, AN Wireless, and I briefly
considered a "Big Bertha" monopole.  I saw a very nice installation at K7RL.

I had determined that my property wasn't wide enough for three guy points.

After several rounds of engineering calculations (required for my county's
building permit), I came to the conclusion that I had to rethink my
"self-supporting" requirement to make the installation affordable.  I ended
up with 70' of Rohn 55, "star" guying with black phillystran at the 50'
level.  

I painted the tower to blend in with the surrounding vegetation.  The bottom
10' of the guys are EHS and are visible (and need to stay that way to avoid
walking or driving into them), but the rest of the tower and guys sort of
disappear into the background.  If you look up, you see the antennas.  But
they're not in the normal line of sight.  Only my two adjacent neighbors can
see the tower, and they have to look for it.

Having climbed both a  nested crankup tower (you go up maybe 25') and an
appropriately guyed Rohn 55 tower, I very much prefer climbing the taller
guyed tower.  Rohn 45 would probably feel about the same.  I'm sure AN
Wireless and Trylon towers would be just as comfortable.

You've stated that you required a self-supporting tower.  I thought I did
too, initially, but I eventually found that I needed to relax that
requirement to meet my other goals.  The guy anchors just fit in.  I had to
spend a few days with three lengths of 50' yellow cord and a protractor to
find locations for the guy anchors, but it was well worth the effort.

73 de Dick, K6KR