[Milsurplus] Pi- Matching Network: When?

[Mike Feher]

I am pleased to see John Nagle's name here. He and I became close friends
due to our collecting interests. I made numerous trips to his QTH as he did
to mine. This was of course when I lived in Manassas, not far from John.
Thanks for the memories Mike. 73 - Mike

Mike B. Feher, N4FS
89 Arnold Blvd.
Howell, NJ, 07731
732-886-5960 

-----Original Message-----
From: milsurplus-bounces at mailman.qth.net
[mailto:milsurplus-bounces at mailman.qth.net] On Behalf Of Mike Hanz
Sent: Thursday, February 09, 2012 9:59 AM
To: milsurplus List; Old Tube Radios; Boatanchors-qth List
Cc: David Stinson
Subject: Re: [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