Wiring problem - need help!

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alienjesus
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Wiring problem - need help!

Post by alienjesus »

I'm looking for a way to convert an RF coax aerial input into either a composite or S video output, but I dunno if it's even possible. I've not been in any luck looking for simple adapters or whatnot, so I was just wondering what options I might have for doing it. I don't mind the set up being a little unweildy if its still reasonably cheap - I'm not looking for incredible video quality, as it's for being able to connect old consoles to my capture card, and I'd rather not have to go and buy composite or S-Video cables for them all.

Any ideas? I'm a bit hopeless when it comes to this stuff, so anything you can suggest would help!
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Majors
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Re: Wiring problem - need help!

Post by Majors »

Use a VCR.
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alienjesus
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Re: Wiring problem - need help!

Post by alienjesus »

Majors wrote:Use a VCR.

Unfortunately I don't have one. Would a switch box work in a similar way? I might be able to nab one of those.
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Re: Wiring problem - need help!

Post by lordofduct »

analogue or non digital signals (your regular PAL over the air tv that's been broadcasting in your region for years... or the video coming out of your old SNES or MegaDrive) can technically be spliced out of the coax. Digital would require a digital tuner, your HDTV usually does this and it only expects it on the coax line.

But for the regular analogue signals are actually in the same exact composite format that goes across RCAs or S-Vid. Difference is, the audio is composited with the video, and multiple video signals are carried on the same wire in different frequencies (hence the tuner, to tune to a specific frequency).

If you want the tele to make it through, you NEED a tuner in between. May it be hand built or not... because S-Vid and RCAs can't be tuned, they carry only ONE video signal at a time.

But if say you only want one channel (like say channel 3... the common channel your console output on over coax). You can demodulate the RF signal on the coax. In doing so you tune into the specific channel you want, separate the video from the audio, and output them on their respective lines.

They sell devices that do this for you... they're called an "RF demodulator"... as opposed to the "RF modulator" (which is what converts RCAs into coax).

The device is not simple, because unlike going from say S-Vid to RCA (which just combines the luma and chroma of S-Vid), you have to tune to the desired channel and separate the signals apart.


here's a quick example of one:

http://compare.ebay.com/like/3703359697 ... 602_304662

it's also expensive... gross

looking around though it seems the demodulators are very pricey... don't get all excited if you find a cheap one. Make sure its a DE-modulator, not a modulator, the modulator goes the wrong direction.




What do you need this for? If it's for video game consoles it will be easier to locate the RCA, S-Vid, or SCART cables available for the console (depending which are available). If the console ONLY offers a coax out (like say the atari 2600), there are mods you can perform to tap out a composite signal... google around for things like "atari video mod" and you'll see what I mean. All the consoles unless you go back to like the 70's have some way of tapping out composite... just with some basic soldering.
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alienjesus
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Re: Wiring problem - need help!

Post by alienjesus »

lordofduct wrote:analogue or non digital signals (your regular PAL over the air tv that's been broadcasting in your region for years... or the video coming out of your old SNES or MegaDrive) can technically be spliced out of the coax. Digital would require a digital tuner, your HDTV usually does this and it only expects it on the coax line.

But for the regular analogue signals are actually in the same exact composite format that goes across RCAs or S-Vid. Difference is, the audio is composited with the video, and multiple video signals are carried on the same wire in different frequencies (hence the tuner, to tune to a specific frequency).

If you want the tele to make it through, you NEED a tuner in between. May it be hand built or not... because S-Vid and RCAs can't be tuned, they carry only ONE video signal at a time.

But if say you only want one channel (like say channel 3... the common channel your console output on over coax). You can demodulate the RF signal on the coax. In doing so you tune into the specific channel you want, separate the video from the audio, and output them on their respective lines.

They sell devices that do this for you... they're called an "RF demodulator"... as opposed to the "RF modulator" (which is what converts RCAs into coax).

The device is not simple, because unlike going from say S-Vid to RCA (which just combines the luma and chroma of S-Vid), you have to tune to the desired channel and separate the signals apart.


here's a quick example of one:

http://compare.ebay.com/like/3703359697 ... 602_304662

it's also expensive... gross

looking around though it seems the demodulators are very pricey... don't get all excited if you find a cheap one. Make sure its a DE-modulator, not a modulator, the modulator goes the wrong direction.




What do you need this for? If it's for video game consoles it will be easier to locate the RCA, S-Vid, or SCART cables available for the console (depending which are available). If the console ONLY offers a coax out (like say the atari 2600), there are mods you can perform to tap out a composite signal... google around for things like "atari video mod" and you'll see what I mean.
Haha, that probably is a bit out of my price range. A VCR would be cheaper. :lol:

I'm trying to capture the games with my capture card, which supports Composite or S Video input. However, about half of my consoles have RF cables for video, and I can't simply connect that up. In addition, my N64, Dreamcast and Turbografx, which have composite cables, all lag on my TV, which is a cheap, early HDTV, making them unplayable (newer consoles work fine). They work fine however with RF cables.

So basically, I need those consoles to be able to run into a splitter, with an RF connection leaving the splitter and going into the television so I can play the game properly, and another RF connection leaving the splitter, being converted somehow to composite or S video, and then connecting to the capture card so I can record it. I have all of those things sorted except for the conversion bit :?
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CRTGAMER
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Re: Wiring problem - need help!

Post by CRTGAMER »

A used VCR is the cheapest solution. Even if it has bad heads, it will still work for the signal conversion to your capture device. The end video will still be a RF source feed, the worse signal for a capture.

Some of the other consoles you listed support S-Video.
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