W1TR Boat Anchors

Updated 21-Aug-2006  13:23


[back to W1TR Home]


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 Hopkinton, NH to replace the one that I originally got from Herb Gordon’s estate sale in 1973.  I had disassembled that Valiant and rebuilt it into a rack panel unit to match the R-390-A and T-390-A and had them in a large 6 foot Teletype Corporation rack with heavy angle irons to carry the weight.



The R-390-A has been updated to have a product detector in it, and the crystal filters for 100/1000 Hz Bandwidth have been replaced by Collins mechanical filters for 500 and 1200 bandwidth.respectively (for CW and 850hz shift RTTY)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 Introduction Letter

T-390-A RF Section Schematic

T-390-A Balanced Modulator (7360) Schematic

T-390-A Balanced Modulator (Diode) Schematic (Not Used)

T-390-A Speech Amplifier Schematic

T-390-A T-R Switch Schematic  

T-390-A System Block Diagram

T-390-A Conversion Notes 1

T-390-A Conversion Notes 2

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  




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 !