Microtube Wrist Watch

[N5KRC]

I just ran across this post (http://www.techeblog.com/index.php/tech-gadget/wrist-watch-radio-from-1947) about a transceiver wrist watch from 1947. #Up until today, I have never heard of a 'microtube', and figured the wrist watch transceiver was only something Dick Tracy had.

The quote on the page mentions "various military applications". #My question is, were there actually any military applications that anyone has ever heard of? #The only possibility I could think of would be for a low profile transmitter for a spy. #However all of the "spy rigs" I've ever seen from that era were infact small, but still had a standard size socket to accept a tube.

Just curious...

Scott, N5KRC

[W3MIV]

The combination of necessarily low power (given that you would have to power both the RF circuitry and the filaments of the miniscule tubes in classic A-B fashion using tiny batteries) and a necessarily very inefficient antenna (which I think would be a given were it to be worn as shown) would seem to preclude any real-world use on HF, whether by a spy or anyone else.

Interesting that it was being explored just at the dawn of the solid-state breakthrough, which would make such a radio more likely, though the antenna issue would remain a problem.

[N5KRC]

I would agree that the particular transceiver pictured was pretty much worthless and a novelty item. #What I'm curious about are the "microtubes". #I was thinking more about mini-cw rigs, maybe using a pair or more of microtubes, attached to an external antenna such as a resonant wire hung from a tree, or stealth close-line antenna. #The blurb makes mention of various applications. #If that were true, what were, or would, the other applications have been?

Scott, N5KRC

[W3MIV]

Use FETs. Today's equivalent of the "microtube."