On Tue, Dec 9, 2008 at 4:00 PM, Ross Tucker <rjtucke(a)gmail.com> wrote:
(This has got to be the strangest cross-post I've ever done.)
I have just taken a bet from a friend to challenge my geekiness. I was
telling him about my love of Vintage Technology and he proposed that I
combine two hitherto separate hobbies and see what happens. The
topics: the DEC PDP-11 minicomputer (vintage: 1970s) and vacuum-tube
ham radios (vintage: 1960s). I do sincerely apologize for
cross-posting, but I am rather younger than either of these
technologies (vintage: 1984) and this seems like a monumental
My question for y'all: how could I possibly design+build a project
that uses both of these technologies? My thought is to port some radio
receiver Digital Signal Processing (DSP) application into PDP-11
assembler, compile and run it via emulator on my PC, then use it with
the vacuum-tube regenerative receiver that I built a few years ago...
Does anybody know if PDP-11 UNIXes even had the capability for a
Well, you could look at "Votrax" on Wikipedia. Allegedly, the first
words spoken by a Unix system at Bell Labs, using its Votrax
synthesizer, were "file not found".
Things that are now known as "sound cards" were called A:D and D:A
converters back in those days. And there were a fair variety of them
available for both Unibus and Qbus systems.
Or, to get ambitious, I would LOVE to design some
interface circuitry between PDP-11 digital circuitry and vacuum-tube
electronics... The challenges are legion: the tube side of the circuit
operates around 350V DC levels with radio-frequency (RF) signals at 7
MHz (almost the clock rate of some PDP-11s!) and I don't have the DEC
Handbooks, but I'm pretty sure that even those ancient pre-TTL
circuits operate below 350V!
The vacuum-tube circuits may be running from 350 VDC but somewhere
there are low-level inputs from which everything is amplified. Think
carl lowenstein marine physical lab u.c. san diego