Thanks for an interesting article.
I did a little reverse engineering from the KYW 1934 "4 square" picture
and commentary. A figure 8 pattern was the objective.
It seems to have used 8 radials elevated 10ft per tower. The text says
"55,000 feet of wire" in radial "cages". A little tough to tell but I
can resolve 3 or 4 wire cages. For a frequency of 1020Khz and 32
radials/4 wire cages that is roughly 1/8wl. Or maybe ~3/8wl if they are
3 wire cages. A 200ft tall vertical. Whatever it was, they could put
50Kw into it.
The reference book of patterns for 2 and 3 element verticals is
Directional Antennas, by Carl E. Smith, E.E., Cleveland Institute of
Radio Electronics, 1946
and is available in pdf from scribd.com
It has hundreds of fascinating patterns created by Carl Smith's analog
computer. Antenna patterns for every possible need, if you have the
space and expertise to work out the feed.
One comment in article had me wondering. "The towers were fed by
individual transmission lines from a phasing circuit that separately
controlled the current and phase of each tower."
The 4 square was replaced with two 450ft towers for "increased radiation
efficiency" in 1949 per https://www.broadcastpioneers.com/kywstory.html
Some pretty clever engineering by pioneers 88 years ago.
Grant KZ1W
On 3/29/2022 09:31, Radio KH6O wrote:
This article describes the history of the development of directional MF
antennas on our neighbor, the AM broadcast band.
73,
Jeff KH6O
https://www.radioworld.com/columns-and-views/roots-of-radio/the-development-of-the-directional-am-broadcast-antenna?utm_source=SmartBrief&utm_medium=email&utm_campaign=0028F35E-226C-4B60-AC88-AB2831C8A639&utm_content=8E01A4B9-193C-4BAE-B25D-23D973D5E345&utm_term=5e35c2b9-3044-4235-9961-04d879406e09
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