[Premium-Rx] History of the WJ-8711

Sun Nov 18 12:16:51 EST 2018

Paolo, I think they were referring to a DSP implementation of a 100Hz band
pass filter.

Best, Francesco K5URG

-----Original Message-----
From: premium-rx-bounces at mailman.qth.net
[mailto:premium-rx-bounces at mailman.qth.net] On Behalf Of Paolo Viappiani
Sent: Sunday, November 18, 2018 7:27 AM
To: Terry O'
Cc: Premium -RX
Subject: Re: [Premium-Rx] History of the WJ-8711

Hi Terry O':
I appreciated very much your report about the development of the WJ-8711 HF
receiver.
But there are two statements by Rick Lober with which I do not agree, both
of them appear in its phrase: "Using DSP, the team was able to achieve a
narrow band IF filter of 100 Hz - a first and great for pulling CW out of
the noise. Tuning step size was as low as 1 HZ - another first - all due to
the use of Digital Signal Processing in the IF section (sometimes called
software defined radio now)".
For duty of truth, a narrow-band 100 kHz IF filter had been already used (as
an option) in the WJ-8718-9/MFP receiver, I own one using such a narrow
bandwidth and that was built in 1985. Furthermore, the 1-Hz tuning step size
had been already successfully used both in the WJ-8718A and in the
WJ-8718A/MFP (as an option) from 1982-1983 up; again, I own both the
mentioned receivers, please look at their pictures in my ER paper (part 1 in
Electric Radio #335/April 2017, pages 36-47, part 2 in Electric Radio
#337/June 2017, pages 18-28).
73,
Paolo

Inviato da iPhone

Il giorno 18/nov/2018, alle ore 00:38, Terry O' <watkins-johnson at terryo.org>
ha scritto:

> Rick Lober was the manager of the Gaithersburg facility during the
development of the WJ-8711.  For those of you who don't use (or have a low
opinion of) Facebook, below is what he just posted in the BlackRadios group:
> 
> Best,
> Terry O'
> 
> About 1990, one of WJ's larger customers asked if a receiver could be
designed with the high level of performance found in the popular WJ-8718 HF
Receiver (selling for about $15,000-18,000 at the time) but near the cost of
the Japanese ICOM units they were buying but were not happy with. They set a
goal of $3000 and told us they would buy 1000s if WJ could pull this off.
> 
> Bill Bruff, who was division manager at the time, agreed to fund the
product with R&D. The customer placed an $18,000 order for 6 production
units at $3,000 each (no NRE...) with a delivery time of 9 months (a very
short development period for a project like this). Novel "like the book"
Fullen was the sales lead who booked this whopping first order.
> 
> Steve Hedges was selected as Project Engineer and put together a great
team. I led the overall program which included working with purchasing and
manufacturing to help in hitting the cost target while Steve's team knocked
out the design.
> 
> Requirements definition was key and once set, the team worked hard to
avoid feature creep. The only way to hit the cost goal was to use a DSP
based IF section - a first for WJ. Rockwell-Collins (of R-390 fame) did
release a DSP HF Receiver about 1-2 years ahead of us but the unit drew lots
of power, was expensive and had heat issues. Two years later, technology had
advanced and the time was right...
> 
> The design team settled on a single board radio that included the RF
section and A/D converter (a 1 bit Sigma-Delta type) followed by a single
Motorola 56000 DSP chip that would perform all the functions usually done by
analog IF circuitry in the conventional receivers of the time. The HF
preselector was an option (as it was in the 8718) and the rest of the unit
included a switching power supply and front panel board.
> 
> Extensive time was put into the front panel layout and control software to
insure it was intuitive and included all memory and scanning features along
with the infamous WJ large tuning knob that the customer insisted on. Bob
Watson analyzed all of that in his usual detailed manner.
> 
> Using DSP, the team was able to achieve a narrow band IF filter of 100 Hz
- a first and great for pulling CW out of the noise. Tuning step size was as
low as 1 HZ - another first - all due to the use of Digital Signal
Processing in the IF section (sometimes called software defined radio now).
> 
> About 50% of the way thru the program, I asked Steve what the DSP
utilization was - he stated it was nearing 90% - I about panicked and asked
why not add another DSP to share the load. Steve and team assured me they
could tighten up the code, that the cost goal was paramount, and adding
another $100 chip was not going to happen - they were a determined bunch!
> 
> We had the same level of commitment to that goal in purchasing and in
manufacturing - at times the staff was trying to save pennies and between
the DSP loading issue and everyone doing backflips to save a cent I wondered
if we would miss the forest for the trees and end up with nothing. In the
end, engineering pulled it off as did the purchasing and manufacturing team.
> 
> The night before the customer was to arrive for sell-off of the six units,
the team went late into the night. I decided to put my engineer/former HAM
hat back on and play with one of the units using some real signals. At about
11 PM, I found that the USB/LSB sidebands were reversed (or maybe they were
mirrored...). Steve grabbed Al Blount who was the lead DSP engineer on the
project and the code was corrected. The team went home about 6 AM, showered,
put on ties and showed up at 9 to meet the customer. 3 hours later the 6
units were sold off with a few minor issues. Steve and team had pulled it
off in 9 months and I was honored to be involved in a "once in a career"
effort.
> 
> In the end, 1000s were sold and other configurations were designed
including a half rack unit with front panel and a blank panel computer
controlled unit.
> 
> In addition to our primary customer, 100s of the half rack version were
also used by the BBC in London for the "BBC World Service" - a shortwave
monitoring system that transcribed international broadcasts. They wanted the
best that was out there for this important service.
> 
> We also entered the Shortwave Listeners/HAM radio market with the unit and
called it the HF-1000 - - but that's a story for another day...
> 
> 
> 
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