CW HAM TRANSMITTER - 1948
Design based on a Oct' 1948 Radio & Hobbies (Australia) Magazine article (scans below).
Radio Ham's HF "entry level" 7 Mc/s (40 Metre Band) CW (morse) transmitter circa 1940-50's.
Quartz Xtal frequency controlled oscillator (FT243).
Uses 6V6 GT oscillator and 807 Power Amplifier.
Runs approx 40 watts DC input to final stage.
Power supply is more modern with silicon rectifier diodes, zener diode voltage regulators etc.
3 pos'n switch rx-tx-spot:
rx: reception only
tx: receiver muted tranmitter will radiate when morse key pressed (cathode keying)
spot: oscillator energized, and receiver working; allows receiver to be tuned onto same freq as transmitter (AKA "netting")
3 pos'n metering switch :
Ik oscillator (tune for dip)
Ig final (tune for max)
Ik final (tune for dip - resonance)
When linked with US military command receiver BC455-B (6-9.1MHz) forms a basic single band station.
Antenna usually a λ/2 centre-fed wire dipole (66' long)
fed with balanced line feeder and suspended as high as possible.
Click on any image to enlarge.