If Filters (Nominal 3 Db Bandwidth In Hz) - Watkins Johnson WJ-8711A Technical Data Manual

WJ-8711A
allowing the subdivision of available memory into
multiple search scenarios. The operator can specify
certain channels to be skipped without having to
delete them from memory. Memory channels can also
be single-stepped manually. In both F1-F2 scan
modes, the step size is user-selectable from 1 Hz to 25
kHz. Up to 100 independent frequency lockouts can
be stored.
An operator can control the WJ-8711A locally via the
front panel or remotely via the serial interface.
Measuring 5.25 x 19 inches, (13.34 x 48.26 cm), the
microprocessor-controlled front panel provides a user-
friendly operator interface with dedicated, logically
arranged controls and large, easy-to-read LED
displays. Figure 1 illustrates the organization of the
front panel and highlights some of the features
available to the local operator.
A majority of the WJ-8711A operator-selectable
parameters are controllable and accessible via an
RS-232 remote interface. RS-485, RS-422, and
IEEE-488 interfaces are optional.
All receiver inputs and outputs are available on the
rear panel of the unit with the exception of the front-
panel-mounted headphone jack. The antenna and
external reference inputs, as well as the signal monitor
and predetected IF outputs, are available on BNC
connectors. Speaker and dual-balanced line audio
outputs are available on a terminal strip along with

IF Filters (Nominal 3 dB Bandwidth in Hz)

56
63
69
75
81
88
94
100
The 900 through 3200 Hz bandwidths are available in SSB detection mode.
113 225 450
125 250 500
138 275 550
150 300 600
163 325 650
175 350 700
188 375 750
200 400 800
dc-coupled audio, RSSI and squelch outputs, and a
mute control input. The RS-232 interface is available
on a 25-pin D-shell connector.
An operator can use the WJ-8711A as a tabletop
receiver or mounted in a standard 19-inch (48.26 cm)
equipment rack occupying 5.25 inches (13.34 cm) of
vertical rack space. The internal power supply accepts
97 to 253 Vac (47 to 63 Hz) line power and automati-
cally adjusts to the input line voltage. Total power
consumption of the unit is less than 35 watts.
A tunable IF notch allows an operator to tune a
Digital Notch Filter through the selected IF Band-
width (IFBW), in order to eliminate undesired signals
within the IF Passband. Typical notch 3-dB band-
width is 10 to 20 percent of the selected IFBW and
provides 50-dB of rejection (typical). The notch filter
is a nonlinear phase IIR Filter and should not be used
when flat group-delay response is required. Not
available in CW detection mode.
Options
The standard Digital HF Receiver is available in a
varity of mechanical configurations. Continuous
product improvements have also produced significant
enhancements and a wide array of options. See
separate WJ-871Y Options Matrix data sheet for
details.
900 1800 3600
1000 2000 4000
1100 2200 4400
1200 2400 4800
1300 2600 5200
1400 2800 5600
1500 3000 6000
1600 3200 6400
2
7200 14400
8000 16000
8800
9600
10400
11200
12000
12800