In message on Thu, 3 Mar 2011 17:14:53 +0000
tony sayer wrote:

Besides all things radio, I was intrested in modulated light, and we had a
perminant light
beam telephone set up between my room and the shop across the road, the one that
used to be owned by Mr Saul.


We used to do that with a carbon mic based phone set and stakes set into
the ground some distance apart. Set up a sufficient field for it to work
seem to remember a lot of volts were used from those olde dry HT
batteries;!..

My brother and I tried that once! Buried an old chassis at the far end of the garden for
one electrode and used the rising main for the other (the wring in our house was so ol;d
that all we had was 5A 2-pin sockets!)

We were going to drive it with my 10W amplifier - 2 x 6V6 + 2 x 6SN7 IIRC.

That was how we found out that there was a fault in the mains transformer - the
insulation had broken down between the primary and the core and we just managed to get
the mains plug the right (or should that be wrong) way round!

--

Terry