W1TR Boat Anchors
Updated 21-Aug-2006 13:23
Here is the “Boat Anchor” rack… E.F. Johnson Valiant (top), Collins R-390-A (***) (middle), and T-390-A (bottom), and homebrew FSK/AFSK RTTY modem with active filters using an op amp 741 circuit (very bottom).
This Johnson Valiant was recently acquired from the Hoss
Traders flea market in
The R-390-A has been updated to have a product detector in it, and the crystal filters for 100/1000 Hz Bandwidth have been replaced by Collins mechanical filters for 500 and 1200 bandwidth.respectively (for CW and 850hz shift RTTY)
The T-390-A is a SSB/CW/FSK/AM exciter made by reversing the circuitry in the RF and IF sections and replacing the audio amplifier with a speech amplifier. The balanced modulator is a 7360 beam deflection tube with mu-metal shield around it. . This rig was converted in 1974 when general coverage RX/TX rigs, digital readout displays, and PLL digital tuning were not yet generally available.
CONVERSION NOTES: (hand-drawn from 1975)
T-390-A Balanced Modulator (7360) Schematic
T-390-A Balanced Modulator (Diode) Schematic (Not Used)
T-390-A Speech Amplifier Schematic
Johnson Valiant Notes - Driver Section
Johnson Valiant Notes - Amplifier Section
Johnson Valiant Notes - Power Supply Section 1
Johnson Valiant Notes - Power Supply Section 2
Johnson Valiant Notes - MV Transformer
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This is my RTTY demodulator and AFSK / FSK keyer created using a 741 Op Amp circuit for active filters and AFSK oscillator.
The small CRT creates an X pattern for tuning.
The only thing here less than 30 years old is the cart, which was recently purchased from BJ’s !