[Collins] AOR DDS-2A Revisited

[Adam Farson]

Jerry,

That makes me feel good! I guess that our RF design group at Racal in South
Africa was far more avant-garde than we gave ourselves credit for at the
time.

I joined Racal in January 1964, as a new graduate, and remained there until
I relocated to Europe in March 1967. Our principal project was an FM/SSB
tactical military radio system covering 30 to 70 MHz.

The system consisted of a 2W solid-state synthesised manpack set, an antenna
coupler a 100W tube-type HPA and various antennas. As TTL IC's were just
becoming available at that time, we chose a discrete-component approach and
modular "cordwood" packaging. The PLL synthesiser was channelised in 25 kHz
steps. It was compact - after all, the whole radio had to fit in a chassis
the size of an A41 or PRC-10 set. Its performance was quite respectable for
that era - frequency within 1 ppm within 30 sec. of power-on, frequency
stability within less than 1 ppm over -10 to +60 deg. C, composite noise
< -90 dBc, as I recall.

By 1966, with TI and Philips TTL families freely available, we were
developing a TTL-based synthesiser for an HF land-mobile transceiver. One of
my assignments  at that time was the solid-state PA for this radio (100W, 2
to 16 MHz).

Many of our pioneering designs found their way into products sold world-wide
by our parent company, Racal Electronics Ltd. (now a division of Thales).

Best 73, Merry Christmas,
Adam, VA7OJ/AB4OJ
North Vancouver, BC, Canada
http://www.qsl.net/ab4oj/