2
AUXILIARY FILTER:
Function Switch:
To select the PEAK function push button to the IN position. To
select the NOTCH function push button to the OUT position.
Frequency Control: Adjusts the center frequency of the auxiliary peak and notch
circuits between approximately 300 Hz to 3000 Hz.
Selectivity Control: Adjusts the bandwidth of the auxiliary circuits from 40 Hz to almost
flat. To select the PEAK function push IN this control. To select
the NOTCH function push out this control.
PRIMARY FILTER OPERATION
PEAK:
Turn Function Selector to PEAK. Set the SELECTIVITY control to about the 10
o'clock position. Adjust FREQUENCY control for maximum response to the
desired signal. Selectivity can be increased by turning the SELECTIVITY control
clockwise. FREQUENCY and SELECTIVITY control should be adjusted
alternately to obtain maximum selectivity and best signal intelligibility. The PEAK
mode can be used on CW to narrow in on a signal and greatly reduce unwanted
signals. Peak mode is also useful on wider bandwidths such as RTTY and SSB.
Adjust SELECTIVITY until the desired signal just fills the passband and interfering
signals are reduced.
NOTCH:
The depth of the NOTCH filter is approximately 70 dB. Notch frequency is
adjustable from approximately 300 Hz to 3000 Hz. The primary notch filter can be
set to the NOTCH mode by setting the Function Selector to NOTCH. Set
SELECTIVITY control to the 9 o'clock position. Adjust FREQUENCY control to
remove the CW signal or heterodyne. Increase SELECTIVITY (clockwise) to
narrow the bandwidth of the notch. Readjust FREQUENCY control if necessary.
The unwanted heterodyne should become weaker and the desired signal become
clearer as notch selectivity is increased. At high selectivity on NOTCH, the
FREQUENCY control tuning is very critical and the notch frequency is hard to
locate. If the SELECTIVITY control is rotated past the 3 o'clock position
clockwise, the NOTCH depth will decrease. NOTCH mode is very helpful in
removing heterodynes, stations tuning up on your QSO, or CW signals on or near
your frequency. The NOTCH can be used very effectively on AM when two
stations are heterodyning one other. The heterodyning can be reduced by
notching out the interfering tone.
LOW PASS:
LOW PASS cutoff is adjustable from approximately 300 Hz to 3000 Hz with the
FREQUENCY control. The SELECTIVITY control adjusts the steepness of the
cutoff. LOW PASS mode is useful in reducing annoying high frequency static,
hiss and splatter. When selectivity is increased beyond the 2 o'clock position, a