Watkins-Johnson_WJ-8711A_broch_1996.pdf
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 JFrequency coverage from 5 kHz to 30 MHz in 1-Hz steps JHigh dynamic range: +30 dBm 3rd-order intercept typical JDigital filtering provides 66 IF bandwidths up to 16 kHz with exceptional shape factors JAM, SAM, FM, CW, USB, LSB automatically switches to external reference upon application of signal Synthesizer Lock Time . 90 dB, typical) LO Phase Noise .- 110 dBc at 1- kHz offset, typical Reciprocal Mixing .With a desired signal of 25 mV in the 3.2- kHz IFBW, the desired signal- to- noise ratio (SNR) is 20 dB, when an undesired signal 70- dB higher in amplitude and 35- kHz removed in frequency is present. Cross Modulation .With a desired signal of 10 mV, an undesired signal 86- dB higher, 30% AM modulated produces 50 kHz in the 1- kHz IFBW. Internal Spurious .<- 114 dBm referred to the RF input Blocking.An unwanted signal 1 mV separated 20 kHz from a desired signal of 1 mV will not cause the IF output to fall by more than 3 dB. Line Audio Outputs Number of Outputs .2 center- tapped, balanced outputs ISB mode, USB selectable by internal switch or front panel entry RS- 232 .Full duplex, 3- wire serial interface; rear- panel 25- pin female D- shell connector Baud Rates (Both Interfaces).75, 150, 300, 600, 1200, 2400, 4800 selectable by internal switches or front panel entry 8 WJ- 8711A (Maximum) (Typical) 3- dB BWShape FactorGroup Delay Variation (kHz)(3/60 dB)(100% of 3- dB BW) 0.3 1.35:1 50 S 1.0 1.40:1 30 S 3.2 1.25:1 30 S 6.0 1.25:1 40 S 16.0 1.25:1 60 S USB/LSB/ISB (3.2) 1.25:1 30 S IF Filter Specifications MIL- STD- 810D Test Method A. Low Temperature . Test Method 502.2 B.High Temperature . Test Method 501.2 C.Humidity. Test Method 507.2 D.Altitude . Test Method 500.2 E.Vibration . Test Method 514.3 F.Shock . Test Method 516.3 Operating Temperature . 0 to +50oC Storage Temperature . - 40 to +70oC Humidity . 10 cyclic days (240 hours); Procedure III for continuous exposure to 95% RH Altitude . 50,000 ft (15,240 meters) non- operating 24,000 ft (7,315 meters) operating Vibration(1) A.Basic Transporation (secure cargo) Category 1 . Random vibration 1.04Gs non- operating (2 hours) B.Ground mobile (wheeled or tracked vehicle) Category 8 . Random vibration 6.0Gs operating (15 minutes) C.Marine (shipboard vessel not specified) Category 9. Random vibration 1.0Gs operating (2 hours) D.Environmental stress (NAVMAT- P- 9492) . Random vibration 6.0Gs operating (15 minutes for design qualifications) 3.06Gs nonoperating 10 minutes for production screening (ESS) Shock(1). Bench handling (field service) 8 drops total onto a horizon- tal hard wooden surface, operating MTBF . In excess of 10,000 hours; estimated in accordance with MIL- HDBK 217E for Ground Fixed; +40oC environment EMC . EN50081- 1 (radiated & conducted emissions to EN55022, Class B) EN50082- 1 (including IEC 801- 2:1984, IEC 801- 3:1984 & IEC 801- 4:1988) EN55020 (Immunity for Receivers) Safety. IEC 1010- 1:1990+A1/EN61010:1993 Power Requirements. 97 to 253 Vac (47 to 440 Hz) Power Consumption. 35 W, typical with options Environmental Specifications 9 WJ- 8711A WJ- 8711A- 3 Configuration Specifications The WJ- 8711A- 3 configuration is the same as the standard WJ- 8711A with the following exceptions: Options. REF & PRE standard Detection Modes. includes FSK IF Rejection . - 90 dBm Operating Temperature Range . - 5 to +50oC In addition, an operator may use the RS- 232 remote interface to output the string message AXXXXXXXX + BXXXXXXXX + CR (where XXXXXXXX is the receiver frequency) upon activation of the A or B front- panel button. These push- button functions become especially useful when the WJ- 8711A- 3 acts as an RF front end for certain DF applications. Technical Update WATKINS-JOHNSON December 1996 Digital HF Receiver WJ-8711A Specification subject to change without notice.Printed in the U.S.A. WATKINS-JOHNSON COMPANY 700 Quince Orchard Road, Gaithersburg, Maryland 20878-1794 Phone: (800) WJHELPS or +(301) 948-7550 FAX: +(301) 921-9479 Email: Website: 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.
