Topband
[Top] [All Lists]

Re: Topband: History of directional MF antennas

To: topBand List <topband@contesting.com>
Subject: Re: Topband: History of directional MF antennas
From: Renee K6FSB <k6fsb.1@gmail.com>
Reply-to: k6fsb@arrl.net
Date: Wed, 30 Mar 2022 11:50:04 -0700
List-post: <mailto:topband@contesting.com>
available here no membership required.

https://worldradiohistory.com/BOOKSHELF-ARH/Technology/Directional-Antenna-Patterns-Smith-2nd-1958.pdf

https://worldradiohistory.com/BOOKSHELF-ARH/Technology/Directional-Antenna-Patterns-Smith-2nd-1958.pdf

Renée,K6FSB

On 3/30/22 10:25 AM, Grant Saviers wrote:
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
_________________
Searchable Archives: http://www.contesting.com/_topband - Topband Reflector
_________________
Searchable Archives: http://www.contesting.com/_topband - Topband Reflector

_________________
Searchable Archives: http://www.contesting.com/_topband - Topband Reflector
<Prev in Thread] Current Thread [Next in Thread>