30 Aug
2023
30 Aug
'23
10:45 p.m.
On Wed, 30 Aug 2023, William Sudbrink via cctalk wrote:
There were RF modulators. See the November 1976
review of the Poly-88 here
(on page 16):
http://cini.classiccmp.org/pdf/DrDobbs/DrDobbs-1976-11-12-v1n10.pdf
Note the reference to the "Pixie Verter". It is a little cheap circuit
board that takes the composite signal and modulates it onto channel 3. You
will find references to the Pixie-Verter in a number of publications and
user manuals for early video boards. The Matrox and the Cromemco Dazzler
and the Ohio Scientific documentation all reference it. David Ahl in his
"Saga Of A System" magazine article references it. With that, a TV, video
board, RF modulator and a parallel keyboard were much cheaper than any
serial terminal back then. The RF modulator was separate from the video
board (usually hung on the back of the TV) for noise reasons.
In the circles that I was in, the Sup-R-ModII seemed to be the most
common. Oddly, it was on UHF channel 34, although there were plenty of
channel 3/4 ones. Tuning the TV to channel 34 wasn't all that hard,
because it was right below a third tier channel and a 24/7 [speed-freak?]
preacher dude, that provided easy landmarks in the spectrum.
Since the RF modulator needed a power supply, and it was easy to bring
power out from the computer, whereas the 'rents wouldn't let you modify
the family Philco, amongst my associates, it tended to be located at the
computer.
Both the AppleII, and the IBM CGA (even including most of its clones) had
a 4 pin Berg (one pin usually missing as a key) to power and run the RF
modulator.
Terminals were cool if you had one, but cost more.
--
Grumpy Ol' Fred cisin(a)xenosoft.com