Hi,
I have a cunning plan...
I've been messing about with computers far too much recently; which is why I've been a bit quiet on here for a while. One of the things I've been playing around with is 'MythTV'; a free open-source PVR system which runs on top of Linux, turning a PC into a TiVo-like PVR and more.
More info on MythTV can be found here:
http://www.mythtv.org/
I'm pretty impressed with it so far; it's not taken much effort to set up on top of the Gentoo Linux distribution (well, easy for a well-seasoned Linux geek like me at any rate) and, among other things, I've got off-air television (which can be paused), a programme guide, can play DVDs and can record programmes on the hard-drive for later viewing. That's on an old 600MHz PIII box I had lying around and a few odd bits of spare hardware I had anyway. I still need to pick up a digital terrestrial card that'll work with the system, but I spot these cards going for around £35 on eBay.
But, what's all this modern stuff got to do with vintage television..?
Well, while I was messing around getting it set up a thought struck me - it should be possible to get a 405-line signal out of it. For DVD, off-air television (analogue, digital terrestrial etc, depending on the card you shove in) and previously recorded programmes it interpolates and outputs the signal full-screen to whatever resolution you have X running in.
So, in theory, with a graphics card that'll manage the right pixel clock and a bit of effort working out an X modeline we could have a fairly straightforward way of watching off-air telly, DVDs etc on 405-line televisions.
I'm going to look into this some more; get my calculator out and spend a happy hour or two working out the magic numbers for X; then hopefully I should get a video signal out of the thing with the right timings.
One minor problem; rather remiss of me I know; I've not got anything which will display a 405-line signal. Would anyone be able to lend me a 405-line monitor at some point, once I've got something on my 'scope which looks right?
If I can get this going, I think I could produce a modified version of
KnoppMyth - http://www.mysettopbox.tv/knoppmyth.html - the aim being an easy installation on a computer with the right bits in it and you get a source of 405-line content.
More later, I have a few things I need to get out of the way this next week but I should be back in Manton Laboratories in the fullness of time and post some 'scope waveforms if I get anything sane happening
Kat