TEXT IS FROM AUGUST 2008 QST PAGES 33, 35 AND 82  ‰ QST DE W1AW  ƒ

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THE HC4053 IS USED TO SWITCH A BYPASS CAPACITOR BETWEEN INPUT PINS ON U5
AND U6, WHICH NEED TO BE AT RF GROUND DEPENDING ON THE DIRECTION THE MIXER
IS BEING USED FOR AT THE TIME.  TWO 2N7000 FETS ARE USED FOR ADDITIONAL
BYPASSING OF THE MIXER INPUTS.  BECAUSE Q4 ADDS CAPACITANCE ACROSS THE
TUNED INPUT IF TRANSFORMER, AN ADDITIONAL CAPACITOR TO RESONATE THE 10R7
MHZ IF TRANSFORMER TO 7 MHZ IS NOT REQUIRED.  ONE IS SHOWN ON THE CIRCUIT
DIAGRAM AS 0 PF, IN CASE ONE WANTS TO MODIFY THE RIG TO WORK ON 75 METERS.
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AUDIO STAGES DURING RECEIVE, THE AUDIO SIGNAL PRODUCED BY U5 IS AMPLIFIED
USING OPERATIONAL AMPLIFIER U4B, BY A FACTOR OF 100 40 DB AND FEEDS THE
VOLUME CONTROL, OR OPTIONAL AUDIO CW FILTERS.  U3, AN LM386 AUDIO
AMPLIFIER, PROVIDES ADDITIONAL GAIN AND DRIVES THE SPEAKER.  IN CW MODE,
‰  FROM PAGE 82  ‰
GF/368 JA2JW/378 KH6CD/390 W4NU/347 DJ4SO/349 G4ELZ/342 JA1DM/382 JH1GZE/
353 EA6NB/343 JA4XZR/343 K5AQ/364 N7BK/343 VE7SZ/343 W8GMH/347 JA6BJV/342
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