how do I connect a BBC micro to a VGA monitor?

From: Dr. Ido <dr.ido_at_bigpond.net.au>
Date: Sun Feb 1 07:15:13 2004

At 12:01 PM 2/1/04 +0000, you wrote:
>Tony Duell wrote:
>
>>>I would like to connect the RGB TTL output of a BBC micro to
>>>a VGA monitor, does anybody have any pointers - suggestions?
>>>
>>>
>>
>>It's very difficult...
>>
>>The trivial problem is that he RGB socket on a Beeb is TTL level digital,
>>the VGA input is analogue. Trivial, because there's only 1 bit per colour
>>on the Beeb anyway, so a resistor network will convert the voltage levels.
>>
>>The difficult problem is that the scan rates are totally different (VGA
>>is 31kHz horizontal, the Beeb is 15.625kHz). If you have a multisync
>>monitor that will go down to 15kHz (some of the old ones will), then
>>there's no problem, otherwise you've got a lot of work either modifying
>>the monitor or making a standards converter.
>>
>>Probably the easiest solution if you're not a video expert is to use a PC
>>with a TV input card. You could at least feed the Beeb's composite output
>>into such a card (do any such cards exist with RGB inputs?)

The alternative is to use a scandoubler such as a Micomsoft XRGB 1, 2, or
2+. These upscan composite video, S-video (NTSC only) and analog RGB to
VGA. They aren't cheap, (I paid US$200 for my XRGB2) but the quality is
far better than any of the cheap video to VGA boxes I've tried. I use mine
with various game consoles and home computers.

As a side note, any suggestions on how to convert CGA to analog RGB so I
can run my Tandy 1000 through it?
Received on Sun Feb 01 2004 - 07:15:13 GMT