To reduce the Time to Return to Receive Mode When RF is Not Present,
parallel resistor R29 with 22k, 1/4W. This can easily be done internally by
changing jumper J1 (DELAY) from position 1-2 (NORMAL), to position 2-
3 (FAST). This will decrease the relay hang time from 500 msec to
approximately 7 msec.
If a local broadcast station overloads the NOISE ANTENNA amplifiers, it can
be sharply attenuated with a tunable trap, C27 and L2. To activate the trap,
connect the jumper JP2 to position 1-2. By adjusting the variable capacitor,
station frequencies in the 1000 to 1600 kHz range can be trapped. To trap a
station with a frequency between 800 kHz and 1000 kHz, install a 22 pF
capacitor between E1 and E2 on the printed circuit board. If the offending
station has a frequency below 800 kHz, install a 47 pF capacitor between E1
and E2. To deactivate the tunable trap, place the jumper JP2 in position 2-3.
To attenuate signals from local broadcast stations that are picked up by the
external noise antenna, place Jumper JP3 for the BCB Filter in position 1-2.
This places a high pass filter with at least 50 dB attenuation in the stop band
in series with the noise antenna. If one particular station is so strong that it still
comes in despite the high pass filter, use the BCB TRAP to notch it out. See
paragraph above. To deactivate the BCB Filter, place jumper JP3 in position
2-3.
This section gives detailed information on the connections to the ANC-
4. The unit is quite simple to connect and use, but for best results, follow the
guidelines in this manual. See Figure 2 for Rear Panel Connections.
The ANC-4 operates from +11VDC to +16VDC and requires about 300 mA.
5
BROADCAST
STATION NOTCH
REDUCING HANG
TIME FOR BREAK-IN
CW OR AMTOR/
PACTOR USE
HIGH FREQ
OPERATION
(Over 20 MHz)
BROADCAST BAND
FILTER
