David Nebenzahl wrote:

But since the OP allowed the use of active devices (e.g., transistors),
just not ICs, why not build a "real" radio? But simple: how about the
world's most primitive superhet AM radio? or maybe just a "crystal set"
but with an audio amp to increase sensitivity? And how about tubes
instead of transistors?

I'd like to see some circuits for such projects. Say something that runs
off a 9-volt battery, maybe with 1, 2 or 3 transistors.



As a seventies kid here in the UK, we had the wonderful Ladybird book -
'Making A Transistor Radio'.

http://www.theweeweb.co.uk/public/upclose.php?id=1663

The TRF project was a short plank of wood, some screws and brass cup
washers, electronic bits and not a soldering iron in sight!

Some related web sites on that.

http://homepage.ntlworld.com/henry01...bird_radio.htm
http://www.mds975.co.uk/Content/trfradios02.html
http://thedomesticsoundscape.com/wor...ird-radio-book

--
Adrian C