self supporting TV towers

[Dan.Strassberg]

I don't think there was enough room at the site for a guyed tower.
Given the reluctance of the WNAC-TV owners (I think it was General
Tire at the time) to spend money on the station, you can bet that they
would have constructed a guyed tower if they could have. Guyed towers
cost less, which is why guyed towers so greatly outnumber
self-supporters. So you may ask, if the company was so averse to
spending money, why they built a tall tower at all. That, too, was
something they really had no choice about; with the other VHF stations
in the market on tall towers, it was imperative for Channel 7 to have
a competitive signal. At that time, General Tire also owned WOR.
WOR-TV (9) had built a self-supporting tower near Palasaides Amusement
Park in New Jersey, across the Hudson from midtown Manhattan. I think
WOR also could not find the space for a guyed tower. But I guess the
company's experience with tall self-supporters was favorable and
probably encouraged G-T to go ahead with the Boston project.

By the way, the Newton candelabra tower has a very small footprint for
a guyed tower of its height--I believe the smallest footprint for its
height of any tower of comparable height built up to the time of its
construction. As most readers of this list probably realize, the
closer the guy-anchor points are to the tower base, the greater the
vertical load on the tower structure. When the uppermost guys are at a
45-degree angle to the tower structure, the downward force that they
exert on the tower is equal to the horizontal force. When the angle
between the uppermost guys and the tower is reduced to 30 degrees, the
downward force is approximately double the horizontal force. Since the
incremental cost of the stronger tower is not negligible, when the
footprint is sufficiently restricted, it can at some point become
cheaper to put up a self-supporter. And no, I don't know what that
point is.

-----
Dan Strassberg (dan.strassberg@att.net)
eFax 1-707-215-6367

----- Original Message ----- 
From: "Kevin Vahey" <kvahey@comcast.net>
To: "(newsgroup) Boston-Radio-Interest"
<boston-radio-interest@bostonradio.org>
Sent: Sunday, September 27, 2009 11:16 PM
Subject: self supporting TV towers


>I was in Kansas City this week and saw a large self-supporting tower.
> I snapped a pic on my phone and sent it to Scott who replied
>
> KCTV channel 5...this is one of the three or four tallest
> self-supporters in America, along with WHDH, WITI in Mke, and WTBS
> in
> Atlanta!
>
> Now the question I have is - given what happened to WBZ-TV in
> Allston
> in 1954, why would WNAC-TV go self supporting in Newton when they
> moved from Malden.