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 Post subject: Creating Signals for Obsolete Televisions
PostPosted: Aug Fri 04, 2017 10:06 am 
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Joined: May Tue 24, 2016 2:41 pm
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Location: Scotland
Whilst this example refers to UK obsolete systems it is quite versatile and could easily deal with 441 or what have you.
http://www.nostalgiatech.co.uk/Baird%20240%20lines.htm

Peter

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 Post subject: Re: Creating Signals for Obsolete Televisions
PostPosted: Aug Fri 04, 2017 3:36 pm 
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Joined: Jan Thu 01, 1970 1:00 am
Posts: 669
Location: Crystal Bay, NV
Take a look at this web site. Clearly, a quality look at the past.
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Ron


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 Post subject: Re: Creating Signals for Obsolete Televisions
PostPosted: Sep Sun 17, 2017 8:56 pm 
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Joined: Sep Sat 16, 2017 2:06 am
Posts: 13
I haven't looked at the back of our current cable box other than to find the HDMI jack, so I don't know if it has a 75 ohm RF output. My previous cable boxes had a modulator with 75 ohm RF output, typically the output was on channel 3 or 4, sometimes switchable.

Somebody might make an HDMI to analog RF output adapter at a reasonable price, but the ones I found were insanely expensive, they must be some sort of commercial distribution system device.

I found these possibly useful devices on a major shopping web site:

HDMI to analog composite video and audio jacks:
"Portta HDMI to AV/CVBS Composite + Audio Toslink Spdif Coax Mini Converter v1.3 for TV PC PS4 Blue-Ray DVD support 1080p"

Composite video and audio to RF:
"RCA Compact RF Modulator (CRF907A)"

Digital TV tuner with video modulator:
"Viewtv AT-263 ATSC Digital TV Converter Box"


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 Post subject: Re: Creating Signals for Obsolete Televisions
PostPosted: Sep Mon 18, 2017 5:17 am 
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Joined: Apr Mon 16, 2012 5:31 am
Posts: 45
Why 441? What is it to prove?

441 60i in the US was only a short hop to 525 60i and only a relatively minor adjustment to the horizontal oscillator yielded this. In the UK, the jump from 405 50i to 625 50i was greater. The video modulation was positive for 405 and negative for 625 whereas in the US only negative modulation was used.

This is demonstrated by US 441 sets relatively easily modified for later 525. The same was never said for 405 to 625 conversion.


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 Post subject: Re: Creating Signals for Obsolete Televisions
PostPosted: Sep Mon 18, 2017 12:46 pm 
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Joined: Jan Thu 01, 1970 1:00 am
Posts: 630
Location: MI
I believe Peter was using 441 as a proof of concept. This method could be used to generate many different standards.

Darryl

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Aurora obsolete video standards converters: http://www.tech-retro.com


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