405 from digital - for dummies - UK Vintage Radio Repair and Restoration Discussion Forum

Panrock · 21st Jun 2023, 1:30 pm

Time for an admission. This is basic stuff I really ought to know.

Up to now, all my 405-line viewing has been done using an Aurora with an analogue baseband 625-line video source, such as a PVR or DVD player.

But what little 'digital' box is recommended that will connect to my PC and provide an output of 625-line analogue baseband? Then, for example, I could connect my Aurora and watch You-Tube films on vintage sets in real time.

I imagine that switchable 16:9 to 4:3 conversion and HDMI connections would be involved. I can't see a spare port on my PC.

Maybe there are previous threads that already cover this essential technique - or it could be made a 'sticky'? Thanks for any help you can give.

Steve

peter_scott · 21st Jun 2023, 3:19 pm

Hi Steve,

My information is a bit out of date and relies on video cards that are widely available second hand and soft ware that is limited to those.

See: http://www.nostalgiatech.co.uk/240%20lines.htm

Once you have that set-up you can output a wide variety of standards although to change to negative modulation you would need to alter the modulator.

Using VLC player gives you lots of freedom to select letterbox or cropped presentations of widescreen formats.

Peter

Panrock · 21st Jun 2023, 3:46 pm

Thanks Peter. Kat Manton, yourself and others have done pioneering work in this field but don't over-estimate my experience in opening up PCs and hacking them about!

I am hoping that nowadays simpler solutions in the form of HDMI-to-576i converter 'black boxes' would be sufficient. Has anyone any recommendations?

Steve

paulsherwin · 21st Jun 2023, 4:18 pm

Is this the sort of thing you mean? https://www.ebay.co.uk/itm/HDMI-To-S...V/334590947646

Panrock · 21st Jun 2023, 4:21 pm

Hi Paul, I didn't know about 'Youview' boxes. Presumably these are dedicated devices pre-programmed to connect to Youtube and compatible with the current coding algorithm? (Forgive me if this sounds like nonsense.)

I don't really want to have to make room for more equipment. I have a PC. It connects to Youtube just fine. I just need something that will convert its display output to an analogue signal that I can plug into my Aurora and which hopefully will also provide adjustment of the aspect ratio.

Sorry if I'm being fussy, or thick, or both.

(Posts crossed... I'll take a look).

paulsherwin · 21st Jun 2023, 4:22 pm

Sorry, I deleted that post as unhelpful. See the eBay link in #4.

Also see this: https://www.ebay.co.uk/itm/HDMI-to-3...r/203223040077

Panrock · 21st Jun 2023, 4:32 pm

Yes, something along those lines, as long as it is compatible with the Youtube 'signal' and has a 576i (eg. 625-line) mono output available from the scart.

paulsherwin · 21st Jun 2023, 4:37 pm

The device in #6 has RCA connectors rather than SCART so you wouldn't need an adaptor. The audio output will be stereo if the sound is stereo, but you can parallel the two channels with a couple of resistors.

Panrock · 21st Jun 2023, 4:45 pm

Lookin' good.

￭ Support NTSC and PAL two standard TV formats output

I presume this also means it has 480i (525-line) and 576i (625-line) outputs?

paulsherwin · 21st Jun 2023, 4:52 pm

Yes, there appears to be a PAL/NTSC switch on the side. The same gizmo is probably sold worldwide.

Panrock · 21st Jun 2023, 5:07 pm

HDMI Input Resolution:

￭ 640x480@60Hz, 800x600@60Hz

￭ 1024x768@60Hz, 1280x720@60Hz

￭ 1280x1024@60Hz, 1360x768@60Hz

￭ 1600x1200@60Hz, 1920x1080@60Hz

Would the '60Hz' present a problem or would this be converted to 50Hz on the 576i (but not 480i) output? I presume no aspect ratio adjustment on offer here.

thermionic · 21st Jun 2023, 5:15 pm

Hi Steve.

I just use an Amazon FireStick Lite plugged into a small HDMI to composite video box which feeds my Aurora & Hedgehog.

Not PC based, admittedly but works for me really well. The FireStick comes with a small remote control so you don’t need an App to control it.

Hope that helps.

Cheers. SimonT.

Panrock · 21st Jun 2023, 5:25 pm

Hi SimonT,

It's the "small HDMI to composite video box" you mention that I'd be interested in learning more about.

Steve

murphyv310 · 21st Jun 2023, 5:25 pm

Hi Steve.
There are many solutions. I'd certainly not recommend youview boxes but a Roku box and HDMI to baseband converter is also an elegant way round it. One issue is always conversion from 16:9 to 4:3 or 5:4, the Hedghog will do it though.
I no longer have standards converters but two separate PCs running 405 Lines, I do realise you don't want to go down that route but if you see the results you'll not go back to standards conversion as the PC is generating a new 405 line signal. I'd be happy to convert a desktop PC for you.

paulsherwin · 21st Jun 2023, 5:41 pm

Steve, the resolutions you are quoting are what the PC will use talking to the HDMI device and unrelated to the device's analogue output.

The device will just output whatever is on the PC display. You would adjust the aspect ratio, zoom level etc. in software on the PC.

Panrock · 21st Jun 2023, 5:48 pm

As always nice to hear from you Trevor. Now that is some offer! (thanks).

I do have a second PC - one (amazingly for me) that I managed to repair the motherboard on, with new electrolytics - but it is about 15 years old and doubtless too slow to cope with today's YouTube.

All the best, Steve

Paul, I'll reply in a mo.

Panrock · 21st Jun 2023, 5:57 pm

Quote:

Originally Posted by paulsherwin

Steve, the resolutions you are quoting are what the PC will use talking to the HDMI device and unrelated to the device's analogue output.

So it would behove me to check the frame refresh rate on my PC monitor was 60Hz first? Or is the HDMI connected to a 60Hz feed regardless?

Usual warnings about me being clueless apply...

Steve

paulsherwin · 21st Jun 2023, 6:05 pm

The HDMI interfaces will negotiate the available resolutions and you can then choose one. As you will see, there are 4:3 resolutions like 1024*768 and 16:9 resolutions like 1280*720. You may need to experiment a bit to get the results you want.

The output will be just PAL composite video without an aspect ratio as such.

Panrock · 21st Jun 2023, 6:23 pm

Quote:

Originally Posted by paulsherwin

The output will be just PAL composite video without an aspect ratio as such.

And there's no such thing as 60Hz field rate PAL composite, so it must come out right at 50Hz... OK.

Smithdoor · 21st Jun 2023, 6:38 pm

Quote:

Originally Posted by Panrock

Quote:

Originally Posted by paulsherwin

The output will be just PAL composite video without an aspect ratio as such.

And there's no such thing as 60Hz field rate PAL composite, so it must come out right at 50Hz... OK.

Try American , Canada and Mexico we use 60Hz

Dave

21st Jun 2023, 1:30 pm	#1
Panrock Nonode Join Date: Feb 2005 Location: Worcestershire, UK. Posts: 2,504	405 from digital - for dummies Time for an admission. This is basic stuff I really ought to know. Up to now, all my 405-line viewing has been done using an Aurora with an analogue baseband 625-line video source, such as a PVR or DVD player. But what little 'digital' box is recommended that will connect to my PC and provide an output of 625-line analogue baseband? Then, for example, I could connect my Aurora and watch You-Tube films on vintage sets in real time. I imagine that switchable 16:9 to 4:3 conversion and HDMI connections would be involved. I can't see a spare port on my PC. Maybe there are previous threads that already cover this essential technique - or it could be made a 'sticky'? Thanks for any help you can give. Steve

21st Jun 2023, 3:19 pm	#2
peter_scott Dekatron Join Date: May 2003 Location: Edinburgh, UK. Posts: 3,259	Re: 405 from digital - for dummies Hi Steve, My information is a bit out of date and relies on video cards that are widely available second hand and soft ware that is limited to those. See: http://www.nostalgiatech.co.uk/240%20lines.htm Once you have that set-up you can output a wide variety of standards although to change to negative modulation you would need to alter the modulator. Using VLC player gives you lots of freedom to select letterbox or cropped presentations of widescreen formats. Peter __________________ http://www.nostalgiatech.co.uk https://www.youtube.com/c/PeterScott/videos

21st Jun 2023, 3:46 pm	#3
Panrock Nonode Join Date: Feb 2005 Location: Worcestershire, UK. Posts: 2,504	Re: 405 from digital - for dummies Thanks Peter. Kat Manton, yourself and others have done pioneering work in this field but don't over-estimate my experience in opening up PCs and hacking them about! I am hoping that nowadays simpler solutions in the form of HDMI-to-576i converter 'black boxes' would be sufficient. Has anyone any recommendations? Steve

21st Jun 2023, 4:21 pm	#5
Panrock Nonode Join Date: Feb 2005 Location: Worcestershire, UK. Posts: 2,504	Re: 405 from digital - for dummies Hi Paul, I didn't know about 'Youview' boxes. Presumably these are dedicated devices pre-programmed to connect to Youtube and compatible with the current coding algorithm? (Forgive me if this sounds like nonsense.) I don't really want to have to make room for more equipment. I have a PC. It connects to Youtube just fine. I just need something that will convert its display output to an analogue signal that I can plug into my Aurora and which hopefully will also provide adjustment of the aspect ratio. Sorry if I'm being fussy, or thick, or both. (Posts crossed... I'll take a look).

21st Jun 2023, 4:32 pm	#7
Panrock Nonode Join Date: Feb 2005 Location: Worcestershire, UK. Posts: 2,504	Re: 405 from digital - for dummies Yes, something along those lines, as long as it is compatible with the Youtube 'signal' and has a 576i (eg. 625-line) mono output available from the scart.

21st Jun 2023, 4:18 pm	#4
paulsherwin Moderator Join Date: Jun 2003 Location: Oxford, UK Posts: 27,144	Re: 405 from digital - for dummies Is this the sort of thing you mean? https://www.ebay.co.uk/itm/HDMI-To-S...V/334590947646

21st Jun 2023, 4:22 pm	#6
paulsherwin Moderator Join Date: Jun 2003 Location: Oxford, UK Posts: 27,144	Re: 405 from digital - for dummies Sorry, I deleted that post as unhelpful. See the eBay link in #4. Also see this: https://www.ebay.co.uk/itm/HDMI-to-3...r/203223040077

21st Jun 2023, 4:37 pm	#8
paulsherwin Moderator Join Date: Jun 2003 Location: Oxford, UK Posts: 27,144	Re: 405 from digital - for dummies The device in #6 has RCA connectors rather than SCART so you wouldn't need an adaptor. The audio output will be stereo if the sound is stereo, but you can parallel the two channels with a couple of resistors.

21st Jun 2023, 4:45 pm	#9
Panrock Nonode Join Date: Feb 2005 Location: Worcestershire, UK. Posts: 2,504	Re: 405 from digital - for dummies Lookin' good. ￭ Support NTSC and PAL two standard TV formats output I presume this also means it has 480i (525-line) and 576i (625-line) outputs?

21st Jun 2023, 4:52 pm	#10
paulsherwin Moderator Join Date: Jun 2003 Location: Oxford, UK Posts: 27,144	Re: 405 from digital - for dummies Yes, there appears to be a PAL/NTSC switch on the side. The same gizmo is probably sold worldwide.

21st Jun 2023, 5:07 pm	#11
Panrock Nonode Join Date: Feb 2005 Location: Worcestershire, UK. Posts: 2,504	Re: 405 from digital - for dummies HDMI Input Resolution: ￭ 640x480@60Hz, 800x600@60Hz ￭ 1024x768@60Hz, 1280x720@60Hz ￭ 1280x1024@60Hz, 1360x768@60Hz ￭ 1600x1200@60Hz, 1920x1080@60Hz Would the '60Hz' present a problem or would this be converted to 50Hz on the 576i (but not 480i) output? I presume no aspect ratio adjustment on offer here.

21st Jun 2023, 5:15 pm	#12
thermionic Heptode Join Date: Apr 2003 Location: Cornwall, UK. Posts: 963	Re: 405 from digital - for dummies Hi Steve. I just use an Amazon FireStick Lite plugged into a small HDMI to composite video box which feeds my Aurora & Hedgehog. Not PC based, admittedly but works for me really well. The FireStick comes with a small remote control so you don’t need an App to control it. Hope that helps. Cheers. SimonT. __________________ The honesty of imperfection..........

21st Jun 2023, 5:25 pm	#13
Panrock Nonode Join Date: Feb 2005 Location: Worcestershire, UK. Posts: 2,504	Re: 405 from digital - for dummies Hi SimonT, It's the "small HDMI to composite video box" you mention that I'd be interested in learning more about. Steve

21st Jun 2023, 5:25 pm	#14
murphyv310 Dekatron Join Date: Sep 2006 Location: Kilmarnock, Ayrshire, UK. Posts: 5,388	Re: 405 from digital - for dummies Hi Steve. There are many solutions. I'd certainly not recommend youview boxes but a Roku box and HDMI to baseband converter is also an elegant way round it. One issue is always conversion from 16:9 to 4:3 or 5:4, the Hedghog will do it though. I no longer have standards converters but two separate PCs running 405 Lines, I do realise you don't want to go down that route but if you see the results you'll not go back to standards conversion as the PC is generating a new 405 line signal. I'd be happy to convert a desktop PC for you. __________________ Cheers, Trevor. MM0KJJ. RSGB, GQRP, WACRAL, K&LARC. Member

21st Jun 2023, 5:41 pm	#15
paulsherwin Moderator Join Date: Jun 2003 Location: Oxford, UK Posts: 27,144	Re: 405 from digital - for dummies Steve, the resolutions you are quoting are what the PC will use talking to the HDMI device and unrelated to the device's analogue output. The device will just output whatever is on the PC display. You would adjust the aspect ratio, zoom level etc. in software on the PC.

21st Jun 2023, 5:48 pm	#16
Panrock Nonode Join Date: Feb 2005 Location: Worcestershire, UK. Posts: 2,504	Re: 405 from digital - for dummies As always nice to hear from you Trevor. Now that is some offer! (thanks). I do have a second PC - one (amazingly for me) that I managed to repair the motherboard on, with new electrolytics - but it is about 15 years old and doubtless too slow to cope with today's YouTube. All the best, Steve Paul, I'll reply in a mo.

21st Jun 2023, 6:05 pm	#18
paulsherwin Moderator Join Date: Jun 2003 Location: Oxford, UK Posts: 27,144	Re: 405 from digital - for dummies The HDMI interfaces will negotiate the available resolutions and you can then choose one. As you will see, there are 4:3 resolutions like 1024768 and 16:9 resolutions like 1280720. You may need to experiment a bit to get the results you want. The output will be just PAL composite video without an aspect ratio as such.