Not to hijack the information about important work by Hamming, but those interested in Grace will have an easier time locating information about her searching on Grace Hopper, Navy Rear Admiral, Lower Half. Her 1986 David Letterman interview: http://www.youtube.com/watch?v=57bfxsiVTd4

I recommend starting with one of the many breadboard kits that are around. A lot of times they're geared toward kids, but usually that doesn't matter too much. Once you have a chance to read their notes about how things work and get to try it out for yourself, you can start digging into more technical adult-oriented manuals and websites and if you pick well, you'll even have something to use to try your own experiments based on what you find elsewhere. The key is the ability to (mostly safely) experiment and learn what does what and how in a truly hands-on fashion. I like the added flexibility of the spring connectors (Maxitronix Electronic Lab) vs something more structured like the Snap Circuits, but it just depends on your needs, interests and whether there is a child who might be inheriting the kit when you're done.

True, I'd have expected he'd have triggered the ELT manually by now too if he could and that does not seem to bode well.

The optimist that I am, however, recognizes that there are still some viable scenarios by which that is NOT an option (snapped ELT antenna? left the plane not seeing a need and then couldn't get back?) and he could still be alive, were he to be sufficiently resourceful.

Since my understanding is that he's the sort who IS that resourceful, I figure it's worth some time to keep participating in the Mechanical Turk search. Especially since I'm unfamiliar with the exact type of ELT on board and the current capabilities of these devices these days. Used to be 121.5Mhz was all there was and you kinda gotta be in range...