Antique Radios forum closed

[Kirkwood]

Let's see if this one works.......

http://antiqueradios.forum5.info/

[frenchmarky]

<<Veering off the topic, apparently quite a lot if you look at RCA's SelectaVision (CED) video disc system which was basically analog video on a glorified LP if I'm not mistaken. However, you'd still need electronics to read the disc.>>

Yup, they had stereo sound too! If you pry one of them open, it looks similar to an LP record. The grooves are so fine you notice that rainbow effect, such as when you look at a CD while moving it around. Really amazing that they put something close to the quality of a VHS tape movie on a relatively simple vinyl disc! Perhaps in 300 years when all the dvds and laserdiscs have gone pitty, CEDs will be the only way people can watch copies of "Silver Streak" and "Smokey and the Bandit" ; )

[Swing Band Heaven]

The selecat vision system sounds interesting - is there anywhere that provides more information on the system and what it involved? I'd like to find out more.

Moments after posting the above I found this link - posted it here for anyone whos interested.

RCA selecta Vision

S-B-H

[gregbogantz]

That CED site is a good place to find out just about anything you'll want to know about the system. I worked at RCA Records in Indy during the entire development and production time of the CED system, and I consulted on some of the engineering. I knew several of the engineers and managers who worked in the CED plants as they were originally employed in the Consumer Electronics and Record divisions, all of which were in Indy. The system actually worked pretty well by the time the final models were produced - stereo sound, rapid access, still frame, interactive options. But it really wasn't competitive with VHS tape as there was no home recording option with CED, so it, as well as all the other videodisc systems of the day were doomed. Audio CDs were just emerging in the USA in 1983, and the promise of digital video on a small disc was just around the corner. So the analog CED technology, impressive as it was, was eclipsed by digital. Just another example of a formidable technology that drove into a dead end street and died. However, it did yield the ability to directly master into copper which was later given to (a sad story there) Teldec and developed by Neumann into the audio DMM (direct metal mastering) that is still used today for some analog disc mastering.

[frenchmarky]

Nearly 10,000 grooves per inch on a 12" vinyl LP, wow that fact is incredible by itself.
Wonder how much music could have been stored on one of these discs, if instead of video+sound it was encoded and played back solely in a hi-fi stereo sound format? I suspect the calculated answer would be mind-blowing, for an LP anyway.
Anybody have an educated guess?

[gregbogantz]

The main video signal was carried via an FM-modulated RF carrier frequency. And there were several sub-carriers AM-modulated onto the main signal for the audio, control, and other signals. Lots of info was crammed onto that disc. The record spun at a constant speed of 450rpm, and it was 12 inches diameter. There are a number of ways that one could put pure audio onto such a disc, each with its own bandwidth cost and advantages. But the simplest way to look at it would be to simply compare how much pure analog audio with no carrier signal could be contained on this 10,000 LPI record if operated at 33-⅓ rpm. A typical LP has an average groove pitch of about 200 LPI (it varies with loudness), so the CED record would have 10,000/200 or 50 times the recording time if running at 33-⅓ rpm. That would be mono audio, since the CED disc is purely vertical modulation. If you chose to put a supersonic carrier on it, you could get stereo audio out of it, also with the 50 times playing time (using a conventional 45/45 analog stereo system would severely reduce the groove density). Considering that the typical 12 inch LP side runs about 20 minutes, this would amount to 1000 minutes or 16.7 hours. Per side of the disc.

[Energ15]

Hmm I wonder how much data could reliably be stored somehow on a 78? : )

Veering off the topic, apparently quite a lot if you look at RCA's SelectaVision (CED) video disc system which was basically analog video on a glorified LP if I'm not mistaken. However, you'd still need electronics to read the disc.

Yes. I was reading about something similar to that. In the late 20s (before the television tube was invented), John Baird invented what was called the mechanical television or Televiser. It used a disc with a series of holes around it and it spun with a blinking neon bulb behind it and created a picture. Since it worked off of electric pulses (used to flash the bulb), he found that he could record the televiser electric pulses on shellac records and then be played back to display the original picture.

[Swing Band Heaven]

Here is a video of a Baird televisor in operation

[youtube]http://www.youtube.com/watch?v=jptCfnCZTuM[/youtube]

And here is a video of a reconstruction of 30 line tv made in 1967 which recreated a play broadcast using the 30 line Baird system in 1930.

[youtube]http://www.youtube.com/watch?v=1inEyPhtKY4[/youtube]

[MordEth]

It sounds like they have all of their content from the forum that was taken down and they shouldn’t have too much difficulty in migrating that to a new host. I’m personally really glad that I get unlimited storage and bandwidth with the hosting package on which this board resides—my account does the equivalent of 2 DVDs of bandwidth each month.

As long as you have proper backups, though, the permanence of online content can be quite good as long as someone is dedicated to maintaining hosting and a domain name...and any content you care about on your computer should be backed up as well.

Hopefully they’ll be back up soon.

It is always possible to merge the content from their temporary phpBB board to the new one, but it would have been MUCH easier if they’d just imported the databases from what was taken down on the temporary site...

And thank goodness that we have David and John to shield us from the slings and arrows of outrageous cyberspace...!

Remind me to make a graphic: “Content integrity with the the George P. seal of approval™”

Can some one post a link to the new interim site please.

Here you go: Antique Radio forum (temporary)