Hi Larry and the group - -
I've been out of the broadcast engineering business for about 20 years,
but the following is still fairly accurate as far as I know.
Towers are painted in an odd number of alternating red and white bands,
with a red band on both top and bottom. All have at least seven even
length bands, and the bands are not more than 100 feet in length.
Therefore, any tower up to 700 feet will have seven bands, 701-900 feet
will have nine bands, 901-1100 will have eleven, etc. That'll get you
within 200 feet if it has nine or more bands.
Another clue is the number of lights on the tower. Lighting
requirements have changed a bit, but it appears the current rules are
as follows:
0-150' - One or two non-flashing obstruction lights on the top.
151'-350' - One flashing beacon on top and a pair or non-flashing
obstruction lights at the half way point.
351'-500' - One flashing beacon on top and a pair or non-flashing
obstruction lights at each of the one third height points.
500'-700' - One flashing beacon on top, a pair of flashing beacons at
the one half height point, and a pair or non-flashing obstruction
lights at the one-fourth and three-fourths height points. (confusing
info here, think this is right.)
The 151'-350' requirement above used to end at 300 feet where a beacon
and two levels of obstruction lights were required. I once got a call
from a guy needing his tower re-lamped. He said it was 300 feet tall,
and I quoted him a price. When I pulled into his transmitter site, I
saw that the tower only had a beacon and single level of side lights,
indicating a tower under 300 feet. When I asked him, he said the tower
was actually only 299 feet, which he did to eliminate the cost of a
second level of obstruction lights to maintain. Oh, well.
73,
Brad, W5CGH
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