Radio Transmitters: Ancient and Otherwise.

 

These pages contain links to schematic diagrams and descriptions of some simple transmitters which can be built with a minimum number of parts and, if built with care, will work very well. You must have an F.C.C. amateur radio operators license of the proper class to use the transmitters on the air. The transmitters, except for the 813 oscillator transmitter, are usable only on CW (Morse Code) and are ordinarily unsuitable for any kind of voice work, as they are drawn here.

I am very partial to Push-Pull transmitters and/or amplifiers. I thoroughly enjoy their symetry and beauty. And they exhibit certain advantages over single-tube or parallel configurations of two tubes.

Even-harmonics are cancelled, and the tube interelectrode capacitances are in series. Total inter-electrode capacitance is then equal to 1/2 of those of a single tube and 1/4 those of a pair of tubes in parallel, thereby minimizing drift from this source. Also, the primary emitted wave-form generally has much lower harmonic content.

Although all the PP rigs shown here COULD be used as triplers, they will NOT work as doublers, since the even-harmonics are canceled by the push-pull design. When used in tripler service, 40 meter crystals would give output on 15 meters. Tripler service on the air is NOT recommended without extensive testing.

Click on any of the lines below to go to the schematic and description of the transmitter indicated.

1) The classic Hartley single-tube transmitter.

2) A Push-Pull Self-excited Oscillator Transmitter of early design

3) The Original Frank Jones 10 watt, Push-Pull, Crystal Controlled, "Beginners Transmitter" from his book, "The Radio Amateur Newcomer", first printed in 1935 or so.

4) A High-Power Push-Pull Crystal Oscillator Tx w/Power Supply, designed by "Sandy" Blaize, W5TVW

5) This is A Push-Pull, Crystal-controlled, Two-tube, 5 meter Transmitter, designed by RCA in about 1935.

6) A single-tube 813 crystal oscillator transmitter , designed by RCA in 1938; power output:150 watts.

7) A Push-Pull Hartley ECO VFO transmitter .

8) The "Paraset" Suitcase Spy Transceiver of WWII.

9) The Tuned-Plate-Tuned-Grid (TPTG) transmitter - a Tuned-Not-Tuned (TNT) configuration.

Any of these schematics may be printed from your browser. If you wish to communicate with me about these, please send e-mail to me, Kenneth G. Gordon W7EKB, at kgordon2006"at" frontier "dot" com.