On Mar 26, 9:14�pm, Mike Coslo wrote:
wrote roups.com:

On Mar 25, 7:03?pm, Mike Coslo wrote:
I agree that using the worst-case fall-circle rule for a
properly-installed radio tower is usually more restrictive
than is needed.

There are situations where the worst-case scenario
applies, IMHO: Field Day and similar temporary installations.
In those cases, where a tower, mast, pole or antenna may fall should
always be considered. Putting a Field Day station
at the base of a temporary tower may look idyllic but is not
a safe practice.

Very true.

All too common, as well.

Of course. People are used to things like Power poles and even think
nothing of hurtling at each other in automobiles carrying liquids
that are almost explosively flammable. In no way does that make
either actually "safe".

There's safety and then there's the *perception* of safety.
Driving/riding in autos is one of the most dangerous things
most people do routinely, based on the death and injury
rates.

Surely. I can't explain the contradictions, but I suppose that those who
practice those contradictions don't give it a second thought.

People tend to be more afraid of the unknown. Cars are known.

Another one
along the same lines is that people fear for their health from a 60 Hz HV
line several hundred feet from their house, but doin't have a problem
with sticking their head in the near field of a cell phone and talking
for hours a day like that.

I think a better example is to compare apples to apples:

Some people fear the effects of power-line fields, but not the
fields from their house wiring and appliances - even though the
latter may be much stronger because they're so much closer.

Some people fear the effects of being near cellphone towers,
yet not the effects of using a cellphone whose fields are
stronger because they're closer. Opposition to cell towers has
caused the cellphone folks to install lots of small cells rather
than a few big ones, and to use disguise antennas - including
some that look like trees.

Both are cases of ignorance of such basics as the inverse
square law.

This is not to say that RF and power-line fields have no health
effects at all, just that the real risk factors are often
misunderstood.

*They are not quite so used to radio towers however. People have a
fear of the unknown, especially in thies days of safe rooms in
houses, and burglar alarms in gated communities.

There's also the Gladys Kravitz effect.

Hehe, very true.

ABNER!

*And in these days of safety taken to stupid extremes, and housing
developments that won't allow you to have a clothesline in your back
yard, I'm not about to go complaining about that one little
restriction on a potential tower.

IMHO, that's how restrictions get a foothold.

First it's some little rule that doesn't really seem to make much
difference, even though it's grounded more in
fear than in good engineering.

For example, as Dee points out, the utility poles could fall over and
cause extensive damage, but they're not restricted the way towers are.

* * * * They not only can, but they do! We see that one all the time.

SO it's familiar....

Then there's a little expansion of the rule. Maybe it's the fall
circle plus ten percent. Or twenty five percent.

A little here, a little there, and pretty soon you need a property a
couple of hundred feet in every direction to put up a fifty foot
tower.

* * * * That's a mighty slippery slope there Jim! 8^)

If it happens, it must be possible.

* * * * If I go into a zoning meeting trying to get a waiver to the
"restriction" in my neighborhood so that I could put up a tower larger
than allowed, I wouldn't get too far with terms such as "very unlikely"
and typical failure mode" They are going to "worst case" me in a big way.

Tell it to Citicorp.

And I'm not so sure that if I was a zoning officer that I wouldn't do the
same. The question I would ask: Is it physically impossible for the tower
would fall straight over at the base?

Solution: Windmill tower.

If you can get expert evidence that
it is impossible, I might consider it, if not, I will advise you to be
glad that you are living in a modern village development that allows
towers, but you will have to be satisfied with a tower within the
prescribed limits.

What if you had a contractor set a utility pole for use as a tower?

73 de Jim, N2EY