VGA to UHF
March 7, 2010 7:59 PM   Subscribe

VGA to UHF? VGA to Coax to UHF? VGA to RF box? Want to pick up a vintage miniature TV off ebay and pipe video from PC to it.

Don't bother asking why, but I prefer to watch moving images on washed-out, small curved screens on the tabletop than on large, crisp, brightly-lit flat panels.

I was looking at a nice portable television on ebay of a certain vintage. A nice 11'' and a nice curve to it, but it appears to only have UHF input for the antenna.

PC video card only has VGA-out. Would I be needing some kind of RF modulator box to pipe the VGA to, and then something going from there to UHF? I've never really heard of adapters that connect to UHF, but I assume something exists for piping video over that connection.

Probably I should hold out for something that at least has coax on it, but still I thought I would ask. Will this suffer a huge quality loss or will it be viewable (albeit with a Polaroid sort of aesthetic)? Probably I shouldn't be asking this because I think that by my standards it will look fine. For instance, the comments in this thread are not what I'm looking for!

Love,
softy
posted by softsantear to Computers & Internet (15 answers total) 2 users marked this as a favorite
 
I've done this trying to connect SNESs to old TVs back in the day, and the only extra step is VGA to RCA connections.

I think you're going to have to triple step this, and buy two converters and an oldie but beloved piece of hardware.

I am assuming that your TV has a channel 3 and that you mean to say that the antenna connection is twin lead instead of coaxial. I can't think of a reason why one would sell a TV that didn't have channels 2-13.

I am also assuming that this will be a dual monitor setup. I can't imagine trying to navigate windows to play youtube videos on such a setup!

1. A VGA to RCA converter,
2. A RCA to Coax / VHF modulator,
3. followed by an Atari 2600 cable to twin lead hookup. There's other tools out there that do this connection (it's just straight wires inside, no converting) but this is the one I can assume will have enough hobbyist support to make commercialization viable.
posted by sleslie at 10:25 PM on March 7, 2010


If you want to use your TV's UHF input, you need an RF modulator that will modulate the video signal in a UHF channel. If you're in North America, this is going to be a challenge, as most RF modulators sold here can only modulate the signal on VHF channels 3 and 4. Something like this should do (but I can't vouch for it). You'll also need to convert the RGBHV (VGA) output of your video card to an input your modulator can take, in this case composite (usually a yellow RCA connector). Something like this.
posted by Monday, stony Monday at 10:28 PM on March 7, 2010


The portable TV probably has a retractable antenna for VHF, hence no VHF IN connector, to save a few bucks and a little space/weight.
posted by Monday, stony Monday at 10:31 PM on March 7, 2010


So:

1. Video card's output VGA connector to the RGBHV-to-composite converter's VGA input.
2. RGBHV-to-composite's composite output (yellow RCA connector) to the RF modulator's composite input (yellow RCA connector)
3. RF modulator's UHF output to the TV's UHF input.

The last hookup might require a dongle like the one sleslie linked to.
posted by Monday, stony Monday at 10:42 PM on March 7, 2010


This is exciting! Great replies, esp. the Atari dongle.
I wonder how much degradation I can expect over those three hops.
Here's a pic of the back of the TV from the seller: http://img34.imageshack.us/img34/3097/31125772.png

Looks like a free UHF slot over there unless I'm misinterpreting this.

Your point about UHF modulation is well taken, btw. If there are any more caveats I'd like to know.
posted by softsantear at 11:09 PM on March 7, 2010


Forgot to mention that yes, dual monitors will be in play here, but it's more for locally stored content being launched from the Linux cli. Shouldn't be too difficult aside from the requisite weedwhacking of the xorg file.
posted by softsantear at 11:13 PM on March 7, 2010


Hmm, looking at it, it seems that the terminals on the left would be your VHF input. If it is indeed the case, you could use a conventional VHF modulator.

It seems that the TV's antenna is connected to the VHF input. In this case, you could simply disconnect the antenna and use the VHF terminals to connect the (VHF) modulator to your TV.
posted by Monday, stony Monday at 11:21 PM on March 7, 2010


OH. Yeah, for some reason I read the V as U, I suppose.
I guess this simplifies things. Really a question of just daisy-chaining then, I suppose.
Are there reasons why this wouldn't work?

I'll give it a try. The trick will be avoiding getting killed on cost of parts. If you suggest something other than generic parts (aside from the Atari dongle - looks high quality), let me know.

I'll memail you if I have troubleshooting...
posted by softsantear at 11:27 PM on March 7, 2010


Do you have an old NES lying around? Ours came with an RF modulator and a little dongle to go from coax to twin lead, and the quality didn't seem too awful to me at the time.
posted by Monday, stony Monday at 11:38 PM on March 7, 2010


Come to think of it, I have a Japanese famicom somewhere.
posted by softsantear at 12:05 AM on March 8, 2010


If you want to save a bit of money, keep the quality as high as possible, and don't mind modding the tv a bit, you could:
1) use a VGA->composite converter, and
2) pick up the composite video connection from the tuner & bring it out to a socket on the back of the tv.

That'll save the composite->RF conversion step, which is where you'll lose the most quality. Audio should be easy too; the tuner will usually have a separate audio line to the rest of the cct.

This, of course, assumes some technical experience on the part of you or a friend ;-)
posted by Pinback at 12:20 AM on March 8, 2010


The trick will be avoiding getting killed on cost of parts.

If it's a desktop PC, instead of using a scan converter to convert VGA to composite, you could switch to a graphics card with composite out.

Budget graphics cards sell in more volume than scan converters, so you might find they cost less. Also, it means one less stage of conversion, which may mean better results (depending, of course, on how good a scan converter you have).
posted by Mike1024 at 12:41 AM on March 8, 2010


Unfortunately, I think the japanese Famicon did not include an RF modulator dongle.
posted by Monday, stony Monday at 7:59 AM on March 8, 2010


You don't need that Atari switchbox to hook an RF modulator up to that TV. A 75 to 300 Ohm matching transformer is what you need. It's $5.50 at Radio Shack, but I've seen them for as low as $1 in electronics surplus stores.
posted by zsazsa at 10:15 AM on March 8, 2010 [1 favorite]


@Pinback: I wish, I wish... but that sounds out of my ken.
@Mike: old laptop used to have a nice composite out, this one (newer) stupidly only has VGA out. it's a nasty proprietary integrated chipset and i don't see myself popping in a new one.
posted by softsantear at 3:26 PM on March 8, 2010


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