Date:Thu, 11 Jan 2007 12:03:46 -0500
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From:"Richard L. Hess" <[log in to unmask]>
Subject:Re: Wired: One Giant Screwup for Mankind
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Hi, Jim,
I am pretty sure that there is no RF. It would be called "FM" but I'm
97% sure that these are "Direct" or AM instrumentation recordings,
not FM as the bandwidth generally wouldn't be available in FM. It's
500 kHz bandwidth on the tape -- and I mis-spoke. Two adjacent pixels
going from black to white is a half cycle, not a full cycle, so 500
kHz is the system bandwidth, assuming square pixels of a 320 line 10
fps (assuming progressive) video signal.
Hopefully, there is a timecode (IRIG probably) on the tape that could
be used as a control track for flutter compensation/time base correction.
Remember, this is video, but not recorded on a video tape recorder.
Other channels presumably record medical telemetry. Larry Miller on
the Ampex list worked on instrumentation recorders and indicated that
they were sold in the multiple 100s of thousands of dollars in the
1960s...they were essentially one-offs and very high tech.
Cheers,
Richard
Cheers,
Richard
At 11:46 AM 2007-01-11, Jim Lindner wrote:
>I think that putting together a one off machine with a phase locked
>loop would be pretty straight forward - but rather then even worry
>about that - I would just pull the data off and do a "virtual" tbc of
>it in software. IF there is some sort of control track pulse it would
>be very simple, correction of timing error in software would be
>pretty straight forward to interpolate. In the article (and others)
>there is this persistent discussion of them "fading away"... this it
>unlikely - IF they can find the tapes - it is likely that they were
>reasonably high coercivity so the RF carrier may be a bit weaker -
>but probably still more then good enough to read - particularly
>considering some of the head technology that exists these days.
>Probably not a small project - - but this is a very "do-able"
>one....... of course finding tapes is a pre-requisite. What surprises
>me - is the general surprise that they were "lost" in the first
>place. This is a recurring theme for decades now - and I fear it will
>be repeated for many more....
>
>
>
>Jim Lindner
>
>Email: [log in to unmask]
>
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>On Jan 10, 2007, at 11:17 AM, Richard L. Hess wrote:
>
>>Wired Magazine has written about the lost Apollo 11 tapes -- again.
>>Still not found.
>>
>>This is a good summary, though the last several paragraphs repeat
>>at the end.
>>
>>http://www.wired.com/wired/archive/15.01/nasa.html
>>
>>This would most likely be an Ampex instrumentation recorder.
>>
>>It would take some work, and the timebase would be less stable, but
>>these tapes could probably be played on a cobbled-together system
>>using an audio recorder. The timebase stability of the Ampex
>>instrumentation recorders was better since the heads were right at
>>the capstan (which was grooved).
>>
>>Cheers,
>>
>>Richard
>>
>>Richard L. Hess email: [log in to unmask]
>>Aurora, Ontario, Canada (905) 713 6733 1-877-TAPE-FIX
>>Detailed contact information: http://www.richardhess.com/tape/ contact.htm
>>Quality tape transfers -- even from hard-to-play tapes.
>
Richard L. Hess email: [log in to unmask]
Aurora, Ontario, Canada (905) 713 6733 1-877-TAPE-FIX
Detailed contact information: http://www.richardhess.com/tape/contact.htm
Quality tape transfers -- even from hard-to-play tapes.
