RadioBanter - View Single Post

June 29th 05, 06:03 PM

Gudmundur wrote:

In article . com,
says...

Hi all,

It's me again, attempting yet another mad science project, and I have
practically googled the subject to death before thinking of asking this
group for help:

I am wanting to put video (preferably color but will settle for
grayscale) onto a UHF TV channel for inhouse use only. I am
considering doing it as follows:

1) Convert output of a VGA card to composite video using resistive
combiner
(found a few on net).

And what magic resistive combiner makes VGA into NTSC??? There is
no such thing. There are active models which do this, but if your
VGA output is 640X480 or more, then NTSC will make the video suck.
NTSC does not have the bandwidth. Yes you can take a properly modulated
channel 3 signal, run it into a balanced mixer (well almost any mixer)
and add your favorite local oscillator signal and get 2 signals in
the uhf band. LO + ch3 and LO - ch3.

Good luck. Here's looking at ya or at least the unviewable signal.

There are a number of video cards with a NTSC video output in the
S-video format. I still have a couple I used in old PCs to drive a
Commodore 1701 monitor to trick people. My Commodore 128 was connected
to an IBM PC Junior monitor in CGA mode. The look on people's faces was
worth the effort.

--
Former professional electron wrangler.

Michael A. Terrell
Central Florida