Thursday, September 11, 2008

ATSC for ATV? Yes!

Well, maybe. For the acronym challenged, ATSC is the standard for digital television broadcasting in North America. One of the aspects of amateur radio that I have toyed with of late is ATV, or amateur television. Although ATV using broadcast compatible analog transmitters is relatively commonplace, no one that I know of has attempted to transmit digital ATV using the ATSC 8VSB modulation standard. I aim to try to be the first.

I will attempt this by setting up a repeater. The repeater will receive standard analog FM ATV on the 1.2 GHz band and retransmit it using ATSC on the 902 MHz band (hopefully). I sent some mail around and believe I can get tower space on Mt. Chual (near Loma Prieta), which will have excellent coverage of the South Bay.

So to do this, I need to get all the pieces: a receiver, a controller, an MPEG encoder, complete with SMPTE 310M transport stream output, an 8VSB modulator, a custom 900 MHz upconverter, amplifier, mask filter and antennas.

Of all that stuff, probably the most expensive will be the MPEG encoder. I have a potential line on the 8VSB modulator, and the rest of it all is pretty standard stuff. Thankfully, putting pieces together like this should not be a problem, since FCC type acceptance is not required for amateur equipment.

So how will anyone receive it? Well, they would need a downconverter and an ATSC tuner. The downconverter can be easily has from P.C. Electronics. Model TVC-9S would do nicely. You're not supposed to use the government issue ATSC tuner coupons to buy ATSC tuners for amateur radio operations, but if you happen to use them to get yourself an ATSC tuner, there's nothing to say you can't use it for amateur TV reception. :)

It's even possible that in the future multiple encoders could be set up to send on subchannels. But you have to walk before you can run.

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