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Washington, D.C., 1920. "National Radio School." Last seen here in an exterior view. National Photo Company Collection glass negative. View full size.
We have a similar knife switch and fuse arrangement on a wall in the basement of our 110-year-old house. It's no longer connected to anything, but it does give that nice "Dr. Frankenstein's Laboratory" feeling!
In 1920 that would have been darn good advice. Hard to imagine now, but the radio boom was a bigger deal then, than the internet was in 1995. First ever development of a mass media market. It didn't "bust" until the 50s, at which point the same people could have gotten in on the TV boom.
Left to right, looks like
1/ Induction coil with adjustable spark gap at rear.
1/ Transformer with some kind of adjustable thing in the core gap?
3/ 2 volt lead-acid accumulator.
4/ Rotary spark gap for adding whiny sound to Morse code transmisions.
5/ Two inductors with ajustable coupling via hinge. Probably for adjusting the coupling of this entire transmitter-on-a-bench to an outside 500 yard long antenna.
On the architrave is a knife switch for jump-starting whoever is lying on the slab.
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