[BC] Kinstar vertical radiation pattern

[Dan Strassberg]

Although the Kinstar antenna exhibits a horizontal-plane radiation
efficiency at least 98% of that of a 1/4-wave antenna of conventional design
(actually the horizontal-plane efficiency of Kinstar's Configuration A is
greater than 99% of that of a conventional 1/4-wave antenna), the FCC said
little (except by inference) about the vertical radiation pattern. One
should be able to postulate an infinite number of vertical patterns that
would produce the same horizontal efficiency. Presumably, in concluding that
Kinstar antennas are suitable substitutes for conventional 1/4-wave antennas
for ND stations, there must have been SOME measurements on the vertical
pattern, although I did not notice any mention of such measurements in
Kintronics NAB paper. If such data exists, it certainly would be nice to see
it. The most obvious place in which vertical-pattern data would be helpful
is in determining whether critical-hours power limitations for Class B and D
stations using Kinstar antennas should differ from the limits for stations
using conventional 1/4-wave antennas.

Locally, here, we have another interesting case--a CP for a DA-2 station on
a former Class IA channel to increase its night power. I believe that the CP
must have been tolled because I think it has officially now expired.
Supposedly, the steel for the one additional tower to be added to the night
array was on site waiting for the riggers to arrive when the town in which
the Tx site is located denied a building permit for the additional tower.
(That may or may not be the true story, but it's certainly a good story.)
Provided that it can be established that the Kinstar antenna exhibits a
vertical pattern that is indistinguishable from that of the conventional
1/4-wave tower described in the CP, the station might be able to build out
its CP using a night array that consists of the two existing 1/4-wave towers
and the five 60' utility poles that constitute the Kinstar. The consulting
firm that designed the array is thoroughly competent, but without a model of
the Kinstar's vertical pattern, it appears that they have their work cut
out for them to establish to the Media Bureau's satisfaction that an array
comprising a mixture of antenna types will perform in the same way as one
constructed of conventional towers.

--
Dan Strassberg, dan.strassberg at att.net
eFax 707-215-6367