This is the Ca. 1930s Crystal Controlled CW Transmitter in the NEWSM collection.
This Crystal Controlled Transmitter is designed to have a more stable frequency control than the TPTG and TNT transmitters in the NEWSM collection. Instead of using a variable capacitor to adjust the transmit frequency, it uses a crystal controlled oscillator. This one has an UX-210 tube (8V Filament, 425Vmax 425V@ 22mA, 1540mW Max Power) for the RF oscillator, and an RCA-247 pentode tube (2.5V Filament, 250V Plate Voltage Maximum, 22mA Plate Current Maximum, 3100mW Max Power) for the Crystal oscillator.
The crystal for the oscillator was made from a quartz eyeglass lens. We need to reverse-engineer the schematic for this transmitter to determine what power supply is needed.
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References for TNT (Tuned plate Not Tuned grid) transmitter
- Building A 1929 Style TNT Transmitter, well illustrated build by VE7SL, Steve McDonald
- Planning and Building Transmitters, form 1934 ARRL Handbook (also referenced in above text)
- The Planning and Building of an Award-Winning TNT, by Nigel Wiegand, W0VLZ. Includes links to
videos of the TNT transmitter that he built. - The Saga of the TNT Transmitter, 1981 story of how W2SN addressed numerous hurdles while
building his TNT transmitter - The Single Control Transmitter, by George Grammer, Dec., 1929 QST (also referenced in above text)
- The TNT – A 1929 Single Control Transmitter, by Steve McDonald, reference on the Antique Wireless
Association Project Files page. - Vintage CW Transmitters, by Gary Poland. Illustrates and describes several reproductions of classic
1920’s transmitters, including the TNT built by Gary Poland, W8PU