Actually John, I am a little surprised that Mal seems to be of the
opinion that something as sophisticated as a "crystal set" might be
required. I seem to recall that the earliest experimenters used far less
sensitive circuits and devices. The lesson of course being that they had
little idea how far their radiated signals were reaching until they had
receivers sophisticated enough to "hear" them. (Note to Mal: for "hear"
read 'demodulate, 'decode', etc./, etc.) 

'Tis all still true, of course!
-- 
73 es gd dx de pat g4gvw
 qth nr felixstowe uk
(east coast, county of suffolk)