On 09/09/2018 22:32, Bob Wilson wrote:
... There was a lot of hum out of the system with a 300 watt
audio amp feeding the speakers!


Somewhat reminiscent of the opening sequence in
one of the Back To The Future films!

Or, going back some years to the April Edition
of Wireless World and the article by the
Dutchly-named George Izzard O'Veering.