30 Jun
2003
30 Jun
'03
1:48 p.m.
Those little RF boxes don't really convert from composite to RF, they
just provide a switch and a connection to a TV antenna input. The
output signal from the computer is already RF. Actually, what I
generally do with machines that have RF out only (i.e. Atari 2600) is
to just go to Radio Shack and get an RCA to F type screw connector
adapter. It's much smaller, and gives much better picture than those
little metal boxes do. It just doesn't provide a switch. What I want to
do is to actually input a true composite video signal into the TV. Of
course, this can be done by using a broken VCR with A/V inputs and a TV
output, but I want to modify the set as a learning experience, as well
as to create something useful for old computers.
Ian Primus
ian_primus(a)yahoo.com
On Monday, June 30, 2003, at 09:17 PM, John Rollins wrote:
I would think the easiest and cheapest way is to use a
plain old RF
modulator box that will put composite video on to channel 3 or 4. I've
taken apart one or two and they seem to have little more than a few
coils and small parts, a far cry from the rack mounted cable TV
modulators I just picked up(ooohh... so many trimmer caps and
coils...). I don't know a whole lot about it, but I'm slowly learning
as my interest in fast scan ATV increases... The converter box I have
goes with my TI-99, I probably have one in the box with my C-64, too.
I think you can still get them at Radio Shack. Otherwise, all you need
to do is dump the composite signal into an AM modulator and then
through a transmitter that the TV can pick up. I would guess these
small boxes having only coils just use a tuned circuit for channel 3
and the voltage from the composite signal to provide the signal. But
then I'm just guessing, I've never poked and prodded those little
boxes very much, I think I'll go do that now(when I find it,
anyhow...).
I have read a lot about the SWTPC TV Typewriter,
and I am interested
in how people modified a black and white TV for a video monitor. I
have an old black and white set that I thought would be fun to modify
for use as a video monitor. Now, granted, I don't really need another
composite monitor, I have plenty of old Apple monitors that will do
the same thing, I just thought it would be fun, since it would be a
challenge to find where to input the signal and how to do it. I found
the PDF of part of the SWTPC TV Typewriter manual on a web site, and
it explains the process, although not in great detail, and references
a circuit diagram of what needed to be added, but the diagram is
nowhere to be found. Does anyone have any instructions or hints that
they may be able to give me? Has anyone done this before? Any advice
would be appreciated.
--
/------------------------------------\
| http://jrollins.tripod.com/ |
| KD7BCY kd7bcy(a)teleport.com |
\------------------------------------/