[Premium-Rx] wj 205 / RS-160 receiver

[Terry O']

The 205 and the Pan-Man RS-160 system was the first electrically 
scanning receiver.  It was a huge step forward for WJ and sold very 
well.  I have several reports of these systems being still in active duty.

Some years ago I saw an RS-160 system with a 205-2 receiver, which added 
alternating pan-sector to the impressive features of the 205, running 
seven tuners in a CSU-160 covering 2-1000 MHz and displaying 14 traces 
on a large HP 1300A X-Y monitor.  Seven traces showed the compete 2-1000 
MHz scan and in between each were seven sectors, in this case various 
ham bands, the civilian and military aero bands and, at the time, the 
analog cell phone band. The resolution was good enough to see chunks of 
the noise floor rise for spread spectrum communications in the military 
aero band.  For 1970s technology it was very impressive.

The RS-160 was used for acquisition and often the RS-180 was paired with 
it for hand-off monitoring.  WJ made a unit that placed a pip on the 
RS-160 spectrum display for showing the frequencies of up to five 
hand-off receivers.  This made hand-off operation quick and easy in 
those pre-digital days.  The most notable use of this combination was 
for recording the pilot of the Soviet Sukhoi Su-15 that shot down the 
Korean Airlines KAL 007, the recording Pres. Reagan released to the 
press over the vehement objections of the NSA.

Nice system.  I hope you get it up and running.
Terry O'
http://Watkins-Johnson.terryo.org
http://BlackRadios.terryo.org


On 6/26/2014 4:54 PM, Peter Ratuschni wrote:
> It looks like the wj 205 and its documentation is far too scarce.
>
> Finally I concluded that transistor Q2 was installed wrong; first I guess that it must be mounted isolated from the chassis. Next, the wires connecting collector and emitter were interchanged. The collector has to be the regulated negative output and the emitter the negative input which is connected to the rectifier diodes on A12 and to C2-.
>
> Together with the wrong wired mains transformer someone did a very effective repair to death.
>
> Maybe the 205 from 1970 was one of the very first receivers with the automatic pan feature using only semiconductors - the heavy motor-units for tuning conventional tuners were still sold in the seventies. I do have one such wj MD unit, and that makes me recognize how smart the varactor based units are. (Though, I still love the inductotuners).
>
> I hope I can revive the unit. Some of the transistors are hard to find and so it will probably take longer.
>
> b.r.
> Peter