Earliest surviving B&W videotape recording

[Aussie Bloke]

G'day all. A few years back I watched in my video course class at TAFE college a documentary on video recording which was part of the Tim Hunkin "Secret Life Of Machines" series and they showed an extremely rare piece of video footage from the mid 50s which they say is the earliest surviving Ampex B&W videotape recording which I assume dates around 1956 or 1957. This footage appears to be of the Hoover Dam shot by a cameraman standing on the OB van while the van is in motion.

I've plucked it off that show and uploaded the 13 second clip to YouTube http://au.youtube.com/watch?v=uOcEq9LzjxM .

Anyways I really want to somehow get a hold of the full footage of this recording and I need some leads so I was wondering if anyone here can identify this footage and possibly the date of recording?

Cheers
Troy