Bob Duckworth wrote:
> Have a receiver here and power supply is marked 25Hz. USA made for USA
> market.
> Who knows when and where in USA 25Hz was so common that 'consumer
> electronics'
> was manufactured to operate on it.
I don't know about USA, but up until the mid 40's there was a "25 cycle island"
in Southern Ontario, inlcuding Toronto, that was on 25Hz. Also I recall shortly
after I got my first license in the late 40's, working a KZ5 in the Canal Zone
who
was on 25Hz, and got his transformers from Hammond in Guelph, Ontario.
A little historical note on mains frequencies: Back in the days of vaccuum
tubes,
there was a series of high voltage filament tubes, including tubes such as the
117Z4..The 117 volt filament voltage was chosen as the average between 110 and
125
which were the common lowest and highest line voltages in use in the 30's. (Or
perhaps 125 was the typical low-load voltage on 110 volt systems).
Bert VE3QAA
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