"Chris Hogg" wrote in message
news
On Sat, 21 Jan 2017 20:11:57 -0000, Terry Casey
wrote:

In article ,
says...

In article ,
Terry Casey wrote:
Make your own!

I did it when I was about 9 by just folowing some simple
instructions - try the local junior library (if they have
any 'proper' books anymore).

A wireless one? Not bad for a 9 year old.


Ah - overloooked that the wireless requirement is a must.

I think I might have had a bit of trouble getting octal
valves into the bell push ...

Indeed, but there were some very small valves available to the public
in the early 1950's before transistors came along later in the decade.
I remember acorn valves, but there was also a little triode about 3 cm
long and the thickness of a pencil, IIRC. May have been gas-filled.
Both types were used in radio controlled model aircraft.
http://www.r-type.org/articles/art-151.htm

Also Nuvistors -
http://www.r-type.org/articles/art-150.htm