[Premium-Rx] WJ-8711A Additions

[Steve Pappin]

One of our list members donated new WJ-8711A files to the FTP site. The 
manual and appendices should now be 100% complete.

History: I started working on these radios 10 years ago. At the time I did 
not have the sophisticated equipment that I have now. I am starting to 
service them again and I have a few new observations.

Notes:

1) The front end of the 8711A, especially with the pre-amplifier on is 
extremely sensitive, -137 dBm.
2) Connections inside this radio are touchy, AMP IDC and compression 
connectors
3) The front panel is a noise source and does not meet MIL-STD-610 (radiated 
& conducted emissions to EN55022, Class B)
4) The radio is actually a repackaged 8712 with a front panel interface
5) The later firmware versions make the radio much easier to use and control
6) WJ-RCS or other software make the radio much easier to use but add 
computer noise
7) A well grounded steel or aluminum enclosure are necessary to control 
front panel, computer, and internal noise
8) All cables running to the 8711A should be as short as possible and well 
shielded
9) A centralized earth ground is essential to making this receiver perform 
properly

Summary: This radio is actually a micro-controller mated to RF and analog 
sections with a front panel interface. The switching power supply is well 
shielded. The front panel is not well shielded. The tuning encoder shaft is 
a major source of radiated noise. Careful attention to proper grounding and 
cabling are required to fully utilize the capabilities of this radio.

Best Regards,
Steve