What digital communications technology relied on underground biscuit tins?

May 6, 2012 6:04 PM

Searching for an incredibly obscure (and hence impractical?) communications technology I saw outlined in a BBC Micro User or Acorn User magazine in the 8-bit era. Difficulty: biscuit tin.

I could swear I read a piece in a Beeb-focused home computer magazine that involved burying biscuit tins in the ground and communicating between them, maybe over distances of half a mile. I suspect it might have been a Mike Cook article.

I'd love to find a pointer to the original article (if only to prove it wasn't the April issue), but I'd be just as happy if someone unpicked my addled memory and told me what was actually going on there. Radio? Magnetism? Why a biscuit tin?

posted by Leon to computers & internet (8 answers total)

Some sort of single wire earth return circuit?
posted by phrontist at 6:12 PM on May 6, 2012

(I can't imagine why though. More likely the biscuit tin was an incidental means of grounding a radio system.)
posted by phrontist at 6:13 PM on May 6, 2012

If you needed to bury something I would guess it would be an acoustic based system. Maybe very low frequency audio which could travel quite far with the right conditions...what is the resonant frequency of a buried biscuit tin? If you added the right transducer you might be able make something interesting...
posted by NoDef at 6:23 PM on May 6, 2012

Was it the wireless system designed by Nathan Stubblefield?
posted by @homer at 7:14 PM on May 6, 2012

Ground wave radio?
posted by jkaczor at 7:22 PM on May 6, 2012

(Probably identical/similar to Stubblefields)

The main reason ground-effect radio is impractical for digital communication is that it is incredibly low-bandwidth, due to the very-low-frequency ranges involved. (The average 300-baud modem would have been dramatically higher bandwidth...)

However - the same - or, similar technologies are in-use today (*cough* submarine communications...)

I have always wondered if it would be possible to increase the bandwidth of groundwave communications using spread-spectrum technologies...

(Yeah, awhile back I did lots of research on ground-based antennae, radio, etc. Why? I dunno, but the rabbit-hole just kept going deeper and deeper)
posted by jkaczor at 7:57 PM on May 6, 2012

I used to hide under my parents' bed to read old copies of (BBC) Micro User and Acorn User. Halcyon days :) I can still picture the advert for Barbarian II perfectly...

Biscuit tin communication doesn't remind me of anything, but I did only read the gaming adverts and game reviews in depth. There are a few partial archives of these magazines online that could yield results:

http://mags.acornpreservation.org/Micro_User/
http://8bs.com/aumags.htm

Among others - a thorough Google might help.

Good luck from one 8-bit aficionado to another!
posted by NoiselessPenguin at 5:04 AM on May 7, 2012

The ground wave radio looks about right, and the low-bandwidth aspect is ringing major bells. Thanks, guys.
posted by Leon at 2:32 PM on May 7, 2012