Note to John Fletcher: If you check these pages, please send me an email. Rich Jan 9, 05

NEW! 050303 - (Refer to photo #6) 
      I was recently introduced to Brian Smith, the mechanical engineer at Wesgrove in the glory days of 1963. He provided this unused video head assembly to the museum. The head consists of a copper alloy block into which is embedded a very thin mu metal strip. This head is fabricated from two halves that mated together to form the whole. Placed between them, as separator, is a sheet of hand beaten aluminum foil only 4/1,000,000 of an inch thick! This forms the precise gap width necessary for the head to function. The electromagnetic coil assembly, the black object with two electrical contacts protruding, is separate from the gap forming magnetics in this design. I tiny ferrite ring is used. A gap is cut through it, making it resemble the letter C. Onto this c-core, 16 turns of AWG 39 wire are wrapped opposite the gap. The ends of this coil are attached to the contact posts and the entire item is potted in plastic. When energized, the coil of wire induces magnetic force in the ferrite ring. Where the gap is cut, this field abruptly exits, crosses space and physically couples with the mu metal strips, inducing an identical field, albeit much much smaller, across the recording gap.
      All I can say, is this is a brilliant bit of engineering. Inspired for sure. To make this video recorder more fascinating is that the video signal, though heavily processed, was essentially fed directly to this video head and later recovered using the exact same head. This was precisely the problem that was solved at Ampex with the introduction of the FM recording method. Unfortunately, this head had an upper limit that was probably less than 2 Mhz. To record FM would require around three times that.
      Another thing to note about the Wesgrove machine. It was very difficult to make the tape float smoothly over the head at 150 IPS. At these speeds, the tape behaves like a violin bow over a string. It vibrates violently which modulates the video playback, severely impairing the image. It was found that heating the head would reduce this effect. I doubt it could be good for the tape, but there were no studies on tape longevity with this system.