Watkins Johnson WJ-8711A Technical Data Manual
The WJ-8711A is a fully synthesized, general-purpose HF
receiver for surveillance and monitoring of RF communica-
tions from 5 kHz to 30 MHz with 1-Hz tuning resolution.
By combining analog and digital signal processing (DSP),
the WJ-8711A achieves high performance at low cost.
Functions such as noise blanking, IF filtering, AGC,
demodulation, Beat Frequency Oscillator (BFO) and
passband tuning are accomplished through the use of DSP
techniques. Filters with superior amplitude and group delay
characteristics are achieved with digital stability and
repeatability. Standard selectable IF bandwidths (66 in all)
are shown in Table 1. Available detection modes are AM,
SAM, FM, CW, USB, LSB and ISB. A tunable BFO is
adjustable in 10-Hz steps over a +8000 Hz range, and
passband tuning is available to further enhance the recep-
tion of CW signals. Gain control is accomplished manually
or automatically, with fast, medium, and slow AGC modes
available. The squelch threshold is adjustable from 0 to
-135 dBm, or it can be disabled. Enabling the noise blank-
ing feature effectively eliminates the adverse effects of
impulsive noise.
In addition to fixed-frequency tuning, the WJ-8711A
provides fast, flexible scanning. Three scan modes are
available: channel scan, F1-F2 scan and F1-F2 scan with
lockouts. For all scan modes, the dwell time can be set from
0.5 to 20 seconds or infinite. In channel scan mode, 100
programmable memory channels are available. Sectors of
memory can be specified for individual channel scans,
Digital HF Receiver
WJ-8711A
Features
❏ Frequency coverage from 5 kHz to 30 MHz in
1-Hz steps
❏ High dynamic range: +30 dBm 3rd-order
intercept typical
❏ Digital filtering provides 66 IF bandwidths up
to 16 kHz with exceptional shape factors
❏ AM, SAM, FM, CW, USB, LSB & ISB Detec-
tion Modes Standard
❏ Fast, flexible scanning with 100 memory
channels
❏ Large readable LED displays & user-friendly
controls
❏ 3 variable AGC decay settings
❏ Noise blanking & passband tuning
❏ Tunable IF Notch Filter
❏ Internal switchable preamplifier & attenuator
❏ Standard remote interface (optional
Multidrop RS-232, RS-485, RS-422, CSMA,
or IEEE-488)
❏ Built-in self test
❏ Optional Suboctave Preselector
❏ Optional Digital Data Output
HEIGHT
5.25 in (13.36 cm)
DEPTH
20.0 in (50.80 cm)
WIDTH
19.0 in (48.26 cm)
WEIGHT
15 lbs (6.78 kg)
Specification subject to change without notice.
Printed in the U.S.A
.
Technical Data
WATKINS-JOHNSON
May 1996
WATKINS-JOHNSON COMPANY
700 Quince Orchard Road, Gaithersburg, Maryland 20878-1794
Phone: (800) WJHELPS or +(301) 948-7550
FAX: +(301) 921-9479 Email: wj.helps@wj.com Website: www.wj.com
All International sales of WJ equipment are subject to USA
export license approval.
This material provides up-to-date general information on
product performance and use. It is not contractual in nature,
nor does it provide warranty of any kind.