McMurdo Silver 701 Four tubes, 807 final, 80m - 6m
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DESCRIFTION: Model 701 Transmitter is a modernized, post-war example of the basic transmitter featured in most recent editions of the A.R.R.L. Handbook. It consists
of a Tritet crystal oscillator driving an 807 beam power amplifier. It goes well beyond the early design in that it incorporates recent tube and circuit improvements,
includes 6-meter operation, plus a push-pull modulator for phone operation. Compactly and expertly constructed to size only 10" long, 5" high and 5½" deep in cabinet,
it is not only a transmitter of extraordinary flexibility and effectiveness, but probably the most powerful, size for size, so far available.
Model 701 circuit consists of a 6AQ5 miniature beam tetrode fuctioning as Tritet crystal oscillator to deliver output upon crystal frequency, or optionally upon 2nd or
4th harmonic of crystal frequency. This oscillator drives an 807 beam tetrode power amplifier to a maximum of 75 watts plate input on CW, or to 30 watts input for 100%
modulation in phone work. The push-pull modulator employs two 6AQ5 tubes to deliver 14 to 15 watts audio output sufficient to 100% modulate 30 watts plate input to
the final amplifier. Any good carbon microphone may be plugged into the MIKE jack upon the panel, the transmitter supplying microphone current to this, the most
efficient and generally satisfactory type of speech microphone available to the amateur. Key jack is provided oscillator cathode circuit to allow break-in operation.
Fixed antenna coupling coil allows direct feed to a suitable antenna, or through an antenna tuner.