[Boatanchors] [Milsurplus] Pi- Matching Network: When?

[Geoff]

What was the first amateur transmitter to use it as the main tank circuit? 
The Viking I had it in 1946 and Johnson had been quite active in the 
commercial end before that.

Carl
KM1H


----- Original Message ----- 
From: "Mike Hanz" <aaf-radio-1 at aafradio.org>
To: "milsurplus List" <milsurplus at mailman.qth.net>; "Old Tube Radios" 
<boatanchors at theporch.com>; "Boatanchors-qth List" 
<boatanchors at mailman.qth.net>
Sent: Thursday, February 09, 2012 9:59 AM
Subject: Re: [Boatanchors] [Milsurplus] Pi- Matching Network: When?


On Feb 7, 2012, at 5:49 PM, David Stinson wrote:
>> Anyone have any idea when the Pi output matching
>> network appeared?

Looks like May 1931, Dave.  A quick google search brought out this
article on the Windom antenna by John Nagle in the May 1978 issue of Ham
Radio Magazine:

"William L. Everitt, as faculty advisor to the students who worked on
the antenna, contributed much to its development.  Everitt began his
amateur career in 1914 as 2ABI; in 1921 he became 8CRI. When he decided
to go into communications professionally, he dropped amateur radio
because he did not want to have the same vocation and avocation.
Everitt was later to become a prominent author and educator.  He retired
as Dean of Engineering at the University of Illinois and went on to
become Dean Emeritus at that university.

Unfortunately, Dr. Everitt has been ill-treated by the amateur
community.  His work on the off-center-fed antenna is largely unknown
and certainly unrecognized.

Unhappily, the same thing happened to him a second time.  *Everitt was
the first to describe the use of a pi network as a coupling device.*  He
published this work in the Proceedings of the IRE in 1931 (12) and in
Communications; (13) the pi network is also described in his book,
Communication Engineering. (14)

Arthur Collins, W9CXX, of Cedar Rapids, Iowa, recognized the advantages
of the pi network to couple the output stage of a transmitter to a
transmission line, and used it in his transmitters. This application
played an important part in establishing the reputation that Collins
equipment will load up to "anything." Collins described the pi network
to the amateur community in a QST article (15) and in a similar article
in Radio, (16) and the network became known by old-timers as the
"Collins Coupler" instead of, perhaps, the "Everitt Easy Loader." "

References:
12. W. L. Everitt, "Output Networks for Radio·Frequency Power
Amplifiers," Proceedings of the IRE, May, 1931, page 725.
13. W. L. Everitt, "Coupling Networks," Communications, September, 1938
14. W. L. Everitt, Communication Engineering, McGraw-Hill, New York,
1937, page 263
15. A. A. Collins, W9CXX, "A Universal Antenna Coupling System for
Modern Transmitters," OST, February, 1934, page 15
16. A. A. Collins, W9CXX, "The Answers to the Flood of Inquiries
Regarding the Collins Antenna System:' Radio, March, 1934, page 5

John J. Nagle, K4KJ (SK)
Herndon, Virginia
May 1978 in Ham Radio Magazine

So now you know...
73,
Mike  KC4TOS

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