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.

Ian

"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.

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!

David.

You have not explained what sort of water cooled carbon microphone is
used capable of handling high power and which won't be dangereous for
the operator to use.

If you ever wanted to make a replica of the transmitter, I recommend you
contact Trevor Wilson.

His ability to generate hot air would be enough to power boil the water
for the superheated steam turbine easily.

And there's more.

Put Trevor in front of the mic with the promise that he will be able to
contact the outside world if he talks loudly enough to overcome the poor
sensitivity of 1912 microphones and he'll be happy as a pig in a bog.
He'll spray and foam so much while achieving acoustical miracles with
the mouth that you won't need water cooling on the mic.

If you want to transmit extra distances, then tie Phil A to the boiler
after-burner, mention something mildly insultive, and watch the big
meter needle showing RF power zooming upwards towards several thousand
watts.

For more about steam,

http://www.dself.dsl.pipex.com/MUSEU.../rotaryeng.htm

Patrick Turner.