Four bands with two tubes

(Work in progress)

The idea is nothing new, and dates back to before 1936, when an ARRL Radio Amateur's Handbook project titled "A 47-46-10 Transmitter for Four Bands" described the basic crystal oscillator / doubler / final concept using three tubes.

The earliest reference I have so far been able to find to a transmitter where the oscillator / doubler function is performed by a single tube is the July 1946 QST article. Also see VE7SL's Longfeller (PDF).

MOPA

http://www.w7ekb.com/glowbugs/projects/

QST December 1945 A Four-Band 125-Watt Transmitter (three tubes)

QST April 1946 A Self-Contained 60-Watt C.W. Transmitter (3.5, 7 and 14)

QST July 1946 A Beginner's Two-Stage Transmitter by David Middelton (W2OEN)

QST November 1946 A Three band utility transmitter

QST May 1947 Table Top Kilowatt

QST December 1948 Jungle Job - 100 Watts

October 1950 QST "Shielded Construction for the Medium Power Transmitter" Donald H Mix W1TS

Also October 1951 QST A 75 Watt Transmitter for 3 Bands. Doubler is switched out. Seems like a step backwards.

1951 ARRL Handbook p181 A Shielded 150-Watt Transmitter for four bands

January 1952 CQ A Foolproof 11-80 Novice Transmitter

The "Inexpensive 75 Watter" transmitter which uses a 1625 from both "QST" and the ARRL Handbook.

The article entitled "A 75 to 120 Watt CW Transmitter" from the ARRL Handbook.

March 1961 The article, first printed in "QST" magazine, entitled "65 watts at Low Cost" designed by Lew McCoy W1ICP of the ARRL's Technical Staff. We have also included a slightly different version of this article from the ARRL's Understanding Amateur Radio's "Building Transmitters" section, entitled "A Low-cost Transmitter".