Happy birthday, Tom! You look younger than your age (in CQ magazine). I am
a tad more than a year behind you (21-Jan-42).
It seems they were correct about the transistor not replacing the "valve" in
high power amplifier circuits. Hooray for companies like Eimac!
Keith NM5G
-----Original Message-----
From: towertalk-bounces@contesting.com
[mailto:towertalk-bounces@contesting.com] On Behalf Of Tom Rauch
Sent: Tuesday, November 16, 2004 10:28 AM
To: Topband@contesting.com; 160m QTH; towertalk@contesting.com
Subject: [TowerTalk] Vacuum tube 100 years old today
On Nov. 16, 1904 Fleming patented the Fleming valve. The vacuum tube is 100
years old today (exactly 46 years to the day older than I am).
I was an electrical engineering student in the late 60's.
The electronics lab stock room was full of tubes and sockets, and our
benches had 300 volt power supplies. About 50% of our inventory and study
was tube related. I built a complete 500 watt HF station, receiver and
transmitter, from stock room parts in my spare time. Every component
necessary was in the stock room. From a textbook I still use, "Electronic
Amplifier Circuits" McGraw-Hill Electrical Engineering Series 1961, comes
the following quote:
"For many applications a relative newcomer, the transistor, is replacing
vacuum tube types because of the greater inherent reliability, lower power
consumption, and smaller size. However, the complete replacement of the tube
by the transistor does not seem likely, for the latter has shortcomings at
high temperatures and high radiation intensities and in the production of
high power at high frequencies. "
About ten years later I received a call asking if I wanted any of those old
tubes, tube related books, or HV bench power supplies before they hit the
dumpster.
73 Tom
_______________________________________________
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_______________________________________________
See: http://www.mscomputer.com for "Self Supporting Towers", "Wireless Weather
Stations", and lot's more. Call Toll Free, 1-800-333-9041 with any questions
and ask for Sherman, W2FLA.
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