How to build a 'Crystal set' AM radio

Antenna

Attached picture is an article someone discovered recently cut-out from what apparently was a children's section in the (now defunct) Sunday Tribune
from sometime in the 1980s!

How to build a 'crystal' radio - requires no power at all - this could pickup strong MW stations
with a good enough wire aerial with earth and drive a high-impedance type earpiece.

With the Medium Wave radio band since gone into disuse in this country you would be hard-pressed to hear anything if you built this nowadays!

Mention is made of 'Peats' electronics of Parnell street in Dublin as an Irish supplier of components required
which sadly went into liquidation yesterday (2 April 2012) - which had been trading since 1934.

watty

Night time it will work. You'll need to connect an external earth and €5 Tesco metal core washing line external aerial though.

Increase the coil and it will work on RTE1 LW 252KHz (and possibly R4 LW 198KHz) during daytime.

But 1.2V LT 4 x PP3 HT NOS valves are only €2 each.

http://www.techtir.ie/construction/the-herge

But even in 1921 & 1922 the main listening on radio was Valve sets. Crystal Radio by the 1920s was obsolete and only extreme budget end of market near a transmitter and hobbyist.


Radio is fun

Curly Judge

Prisoners of war constructed them during the second world war to listen to the BBC etc, and hear how the war was progressing.
Hiding them from the prison authorities was a major problem.

spurious

I tried to build one of these from a very cheap kit with a Junior Cert. History class of mine.

We got vague 'radio' noises, nothing else, but we had a lot of fun and they got the point that they could have been relatively easily built and used during the war.

ZENER

I was given this book when I was 11 years old and had the poor TV repair guy on Bridgestreet Swords persecuted looking for bits to build it Smuggled it to the Gaeltacht in Cork in 1978 so I could listen to good old Larry Gogan on RTE.

The book started with a basic crystal set with a germanium diode as the detector. I remember scurrying under our kitchen sink to connect to the copper pipes looking for an Earth, my mother was convinced I was trying to electrocute her !!

Sigh . . those were the days

Ken

watty

I must write a modern version of that. I bid for it a few times on eBay, but it goes more than I'm prepared to pay.

I have the Ladybird "The Story of Radio" which is actually quite good.

I have a scan of F.J. Camm's "A Beginner's guide to Radio" (1956 out of copyright). Variations of various valve circuits that can actually be built easily using €2 "NOS" Russian Rod Pentodes on stripboard or prototype board or even screw terminal blocks (as they are wire ended). 1 x D cell and 6 x PP3 will do for power.

His Transistor book in the 1960s is poor in comparison.

The cheapest source of ferrite rod, tuning capacitor, optional IF filter, speaker etc now ironically is to buy a €6 Chinese AM/FM radio and take it to bits. The ferrite rod and tuning cap alone will cost you more! Whether building a "crystal set", valve set or transistor model!



The Clock on that one works fine disconnected from the radio! I have what I think are the connections to use the Clock as a frequency counter too.