Stone age? (was: George Morrow died Wed May 7th 2003

From: Tony Duell <ard_at_p850ug1.demon.co.uk>
Date: Sun May 11 18:42:07 2003

> Given a few basic tools (knife) it would be relatively trivial to make
> something like a crystal radio. You would need to find copper ore (look

Assuming you're back in the Stone Age, a crystal receiver is proably not
the best thing to build. You need to consider the transmitter as well,
and a crystal set is only really useful if you have a modulated
transmitter.

I think I would try to make a coherer (basically a glass (or other
isulating) tube containing metal filings, not too tightly packed). That
would work well for receiving the signals from a spark transmitter (I am
assuming that back in this Stone Age there were no government or
internation restrictions on the use of such transmitters ;-)).A spark
transmitter could be made using an induction coil (lots of copper wire
wound round a bundle of iron wire as the core).

There is a book entitled 'Harper's Electricity Book for Boys' published
in 1907. I think it's been reprinted fairly recently. Although not quite
Stone Age (it assumes you have common hand tools, chemicals, copper wire,
etc), it does cover making many electical devices, including primary and
secondary cells, induction coils, coherers, bells, resistors, etc.

> for rocks that have a bluish-green tint) and some galena. You would

Many other substances will work as the diode. I believe that in WW2,
prisoners of war used coke (the fuel, not the drug) for this purpose.

-tony
Received on Sun May 11 2003 - 18:42:07 BST