f. Adjust potentiometer R8 for minimum tone.
5-4. Q-Multiplier/-Notch Filter
Alternately, readjust both L1 and R8 for the best null.
g. Retune the vfo dial and the rejection tuning. The
The Q-Multiplier/notch filter effectiveness can be
tone may be found and pulled.
increased when RF GAIN control R8 is less than
h Replace the antenna connection on the rear of the
maximum. When the Q-multiplier/notch filter is not
necessary, it should be tuned out of the passband (dial
pointer in the horizontal position). The Q-
The Q-multiplier/notch filter (Waters
multiplier/notch filter does not cause reduction in the
340-A) will operate in the Collins KWM-
receiver sensitivity; therefore, an in and out switch is
2/2A with either the a.c. power supplies
not provided. Variable capacitor C6 in this unit may be
(PP-4151/95 or PP-3990/ FRC-93), the
rotated continuously. There will always be two
mobile direct current (d.c.) supplies (PP-
positions 180 degrees apart at which a signal can be
4765/GRC-159(V) (24 volts)), or the
Collins MP-1 (12 volts). The external
5-5. Use of External Vfo
permanently tuned oscillator (pto) C-
When the external vfo is to be used (only with the PP-
7517/FRC-93 may not be used
4151/FRC-93 or PP-3990/FRC-93), remove the
simultaneously unless the a.c. power
shorting plug from the new socket (J17). Insert the vfo
supplies are used because of heater
Section III. OPERATOR'S MAINTENANCE INSTRUCTIONS
Perform weekly as well as before operation PMCS if:
a You are the assigned operator and have not
The instructions contained in paragraphs 3 19 through
operated the item since the last weekly.
3-22, and 3-24 are applicable for the operator's
b. You are operating the item for the first time.
maintenance duties. Paragraph 5-7 contains the
operator's daily preventive maintenance checks and
The checks in the interval column are to be
services chart. Cleaning is covered in paragraph 3-24.
performed in the order listed.
5-7. Operator/Crew Preventive
Maintenance Checks and Services
Equipment is not ready/ available if:
Item to be inspected
Notch filter tuning
Check to insure that an
If filter is incapable of reducing interference that causes failure of
interfering signal can be
notched out. Use external
signal generator to insert
signal at points in full range
of notch filter tuning.
Section IV. Deleted.