"Ian Iveson" wrote in message
...
David Looser wrote:

Leafing through my copy of "The Practical Telephone Handbook" (1912
edition) - as one does - I came across the description of a transmitter
for "Wireless Telephony". It consists of an alternator that generates 5A
at 60V at the carrier frequency (60kHz) coupled to the aerial via a tuned
step-up transformer. The "modulator" is a water-cooled carbon microphone
connected in the earthy lead of the transformer secondary. The best bit,
though, is that the alternator is driven by a steam turbine. I'd always
heard of "steam radio", I hadn't realised it actually existed!

A turbine doesn't count. It's got to be a coal-fired piston engine with a
funnel and a whistle.

At 10,000 rpm?

David.