Specifications

c.
Second Converter
The 5645 KC output of V2 is applied to the grid of the
12BE6 second
converter (V3) through a crystal filter.
This gives excellent cross mod-
ulation and overload characteristics by providing selectivity before the
gain producing stages.
The cathode, control grid and screen grid are connected in a Pierce
oscillator configuration controlled by a 5595 KC crystal. The
5645 KC
IF signal is applied to the signal grid of this tube where it beats with
the crystal oscillator signal to produce 50 KC output.
D.
50 KC I.F. System
The 50 KC output of the second converter V3 is applied to the grid of the
12BA6 IF amplifier tube V4 through the T-Notch Filter composed of T8 and
its associated circuitry.
Output of V4 is applied to the grid of the last
12BA6 IF amplifier (V-5)
through the passband tuner T9.
The
passband tuner consists of four LC circuits with high Q.
Passband tuning is accomplished by ganged permeability tuning of the
four coils, and variable selectivity is accomplished by changing the
coupling between the four tuned circuits.
E. DETECTOR SYSTEMS
The amplified signal
from V5 is applied to the AM detector composed
of diode D7 and
Q5,
to the AVC amplifier Q4 and to the product
detector diodes through the IF transformer,
Tl0.
When the SSB/CW-AM switch is in the SSB/CW position, the BFO, Q6,
is turned on applying 50 KC voltage to the product detector diodes, and
beats with the IF signal to produce an audio signal across the AF GAIN
potentiometer.
When the SSB/CW-AM switch is in the AM position, the BFO is turned
off, the AM detector is turned on and its output is connected to the AF
GAIN potentiometer.
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