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Re: Turn AM DA's into tourist attractions
Thanks, Rob. I found the Web page at
There's also a second page that describes a 49' version.
Both pages contain a lot of specifications, but an
important spec that I could not find is the efficiency.
I suspect that, at least at the low-frequency end of the
AM band, the efficiency does not meet the FCC minimum
requirements for standard broadcast stations.
However, there is a type of antenna that is almost as
short as the Valcom unit and does meet the efficiency
requirements, even at the low end of the AM band. It's
called a Paran antenna, and there are two or three in
use by US stations. One is at a station in, I believe,
Blaine, WA, near Bellingham, close to Puget Sound and
the Canadian border. The station operates at 650, if
memory serves, with 10 kW-D/1 kW-N ND-U. Another Paran
is in use in Hawaii at one of the synchronous TXs of a
station on 620 licensed to Hilo. That TX runs 10 kW-U ND-
A Paran consists of four short, closely spaced towers
(the WA station's towers are 100' high and are spaced
60' apart, I believe). A wire runs from the top of each
tower to the tops of the other three, forming a massive
top load, which significantly increases the electrical
length. Unfortunately, the FCC does not consider the
four towers to constitute a single radiator, though that
is, in fact, the case. So the FCC does not allow the use
of Parans in directional arrays. I understand that the
concept originated in the middle east--perhaps in Egypt.
I do not know whether there are any directional
installations in foreign countries that use these
I have seen some really outrageous claims made for
Parans. My favorite is the assertion that they
completely eliminate skywave radiation.
BTW, the AM you referred to in CA was on 1540 with 10 kW-
D DA-D. It was licensed to Aptos-Capitola (adjoining
communities) and has been dark for a number of years. It
was already dark when Infinity purchased and turned in
the license to permit increasing the D power of what is
now KYCY in San Francisco (now 50 kW-D/10 kW-N DA-2).
KYCY's day site is now in Milpitas, at the south end of
SF Bay but the night site remains along the Bayshore
freeway south of SF.
> AM however offers a number of possibilities. For instance, there's an
> outfit in Ontario called Valcom which makes helically wound antennas for
> the AM broadcast band. They are only 74 feet tall, and WSHP (1450 kHz, 222
> watts) in Shippensburg, PA, uses one.