[Premium-Rx] WJ Multi-Channel Receiver

[wb5uom at hughes.net]

Dave,
Thank you for taking the time to make that post, I enjoyed the reading very
much!

David/WB5UOM
----- Original Message ----- 
From: "David I. Emery" <die at dieconsulting.com>
To: <premium-rx at mailman.qth.net>
Sent: Saturday, June 21, 2008 2:00 AM
Subject: Re: [Premium-Rx] WJ Multi-Channel Receiver


> On Sun, May 25, 2008 at 06:03:38PM +0200, Francesco Clonfero wrote:
>
> >Hello to the group,
> > I have a nice pristine conditions WJ-8890A/MCR  (MULTI-CHANNEL
RECEIVER ) and
> > I need any kind of information related to the specification and the
possible
> > use of this equipment.
>
> Would that instead be an 8690A ?
>
> There was a family of WJ 8690A and 8691A that was purchased by US
> intelligence and FBI folks in the mid 90s for old fashioned AMPS/NAMPS
> analog cell phone intercept when used with special Windows laptop
> software that as far as I know (the software that is) has never seen
> private hands.
>
> The radios themselves are powerful computer controlled (no front
> panel) synthesized general purpose DSP based VHF/UHF receivers comparable
in
> performance and some features to a WJ miniceptor which can demod AM,
> NBFM of various deviations, FSK, USB, LSB, and some PSK modulations on
> up to 6 channels at once which can be located in two 30 Mhz chunks
> anywhere from 20-1000 MHz and with a frequency extender from 1500-2300
> MHz.
>
> They are capable of outputting the audio in analog form from two
> channels, but also of dumping all 6 as telephone style digital PCM on a
> special T1 interface and to a SCSI disk for recording.
>
> Few if almost any exist in private hands in complete and working
> condition - quite a few were released "demilled" about 7-8 years ago
> missing vital boards and parts and from time to time one of those or
> others shows up on Ebay or at Dayton or other fleas.
>
> There are rumors a couple of collectors have one or more
> complete and working, but like all rumors it is not clear if this is
> apocryphal or not.  Certainly parts of them are in circulation and
> show up at fests.
>
> I believe, but cannot prove it, that the FBI TRIGGERFISH system
> mentioned in the late 90s NY Times bestseller "Takedown" about the
> capture of Kevin Mitnick (by John Markoff) was one of these systems;
> certainly the description of the device the FBI used to hunt down his
> cell signal sounds remarkably similar if indeed it wasn't an 8691A and
> laptop.
>
> There are two models, a rack mounted version consisting of a
> separate tuner box and a IF/signal processing box (the 8690A) and a
> portable suitcase or briefcase version with the same boards and tuner
> packaged more tightly for mobile use in one chassis (the 8691A).
>
> Internally they contain two synthesized tuners that tune in 1
> MHz steps and downconvert 20-1000 MHz to 70 Mhz (with the usual 10 MHz
> reference and low phase noise).  NF on these is around 10 db or so,
> typical of other WJ gear of that era.  BW on these is around 30 MHz...
> In addition there was an external downconverter (intended for INMARSAT I
> believe) that downconverts 1500-2300 to feed the main downconverter
> using the same 10 MHz reference allowing the unit to tune 1500-2300 as
> well with similar phase noise and other specs.
>
> The IF box (or cards) contain tuners that tune +-15 MHz around
> 70 MHz (in 100 Hz steps if I remember correctly) and convert whatever
> they see to I and Q for a DSP chip which does the actual demodulation.
> Apparently the usual configuration contained 6 of these DSP and
> downconverter boards - switchable to the output of either downconverter
> tuner under software control.
>
> The firmware for the DSP implements multiple BW's and detection
> modes... the radio will go from quite narrow to wider than 30 KHz...
>
> Other boards in the box are housekeeping of various sorts and
> bus interfaces for outputting the audio/data....
>
> Kind of an amusing relic, no longer of any use at all for cell
> intercept (even if the software for the laptop was available, which it is
> not) with analog cell having been  turned off (and analog INMARSAT long
> gone too) but a very neat example of 90s SOTA spook gear and certainly
> very usable as a computer controlled general purpose AM/FM/SSB/CW
> VHF/UHF receiver capable of receiving multiple channels such as all the
> channels of a trunking system at once.... or all the 2M  repeaters in an
> area or other similar things.
>
> And I might add, as far as I know the units were not replaced
> with more capable ones in at least FBI hands, but with the wiretaps
> built into the switches (CALEA).   Rumor has it that little off the air
> intercept is being done by law enforcement any more (the NSA is another
> matter of course).
>
> Back to lurk mode...
>
> -- 
>   Dave Emery N1PRE/AE, die at dieconsulting.com  DIE Consulting, Weston, Mass
02493
> "An empty zombie mind with a forlorn barely readable weatherbeaten
> 'For Rent' sign still vainly flapping outside on the weed encrusted pole -
in
> celebration of what could have been, but wasn't and is not to be now
either."
>
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