If Notch Filter; Agc (Automatic Gain Control) - Yaesu FT-767GX Operating Manual

To use the APF, first tune in the desired CW
signal with the APF off, and then switch it on
and adjust the APF control for peak volume on
the desired signal. Turn the APF off before
tuning to a new frequency. See also 84.14
"Tips for CW Operation!.
4.6.7 Ir Passband Snift
The location of the IF passband relative to
the carrier frequency of the receiver in SSB,
CW, AM and FSK modes can be adjusted by the
SHIFT control (inner knob on the control just
below and to the right of the tuning knob).
Think of this control as a sliding window ad-
justment, which allows the receiving passband
(window) to be slid back and forth, providing
different views of the receiving frequency.
Normally, the SHIFT control Is kept in the 12
ofclock position until a desired signal has
been tuned in. Then, if the signal is being
interfered with by another signal just above
or below the desired one, the SHIFT control
can be adjusted to the left or right, respec-
tively, to move the passband window farther
from the interference. Notice also that the
audio tone characteristics of the receiver
change: this is useful in AM reception, sup-
plementing the TONE control.
Note: Before adjusting the SHIFT control,
make sure the NOTCH filter is switched
off. Also, return the SHIFT control to
the 12 o'clock position when tuning to
another frequency.
4.6.8 IF Notch Filter
The IF notch filter provides a means to sup-
press carrier heterodyne interference in SSB,
CW, AM and FSK reception. The notch is acti-
vated by the switch of the same name to the
left of the tuning knob, and adjusted by the
inner knob of the middle control at the bottom
right. Wnile activated, the indicator next to
the NOTCH switch glows green.
The notch filter should be activated only
after the desired signal has been tuned in,
and after the SHIFT control has been adjusted
for minimum adjacent-channel interference.
Press the NOTCH switch and adjust the control
gradually back and forth to find the point
where the unwanted heterodyne suddenly drops.
1f the heterodyne level is stronger than the
desired signal, the S-meter indication will
dip when the notch is properly set. Turn the
notch switch off before tuning to a new fre-
quency or adjusting the SHIFT control. See
also 84.13.3.
4.6.9 AGC (Automatic Gain Control)
1f you have been tuning around the bands you
may have already noticed that the main micro-
processor automatically selects fast AGC when
the tuning knob is rotated quickly. This
allows you to detect weak signals while tuning
across the band, even when strong signals are
present.
While listening to a station, you can select
the AGC decay rate that provides the most com-
fortable reception, using the four-position
AGC selector (small knob, second from the
right, next to DIM). Usually, for AM and SSB,
this will be the 'S! (Slow) position, but when
signals are fluttering, or when looking for a
weak signal you may find 'M' (Medium) or 'F'
(Fast) better, at least until you make con-
tact. For CW, the Medium or Fast positions
will be helpful at higher speeds or under
noisy conditions with weak signals. When the
band is very quiet and signals are very weak,
the OFF position may provide best copy (don't
try this df dt is noisy).
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