Jim Kelley, AC6XG wrote:
"I think Farqaday stilll provides the best explanation."
Yes. Faraday showed d-c had nothing to do with wireless. It was the a-c
motivating wireless electrical coupling.
An Englishman, Faraday, constructed a transformer in 1831. He used two
isolateed coils of wire wound on the same spool. He connected a
galvanometer across one coil. He noticed a brief deflection of the
galvanometer each time he connected or disconnected a battery to the
second coil.
Joseph Henry, a professor at Albany Academy in New York was
independently making the same observations at the same time as Faraday.
When Henry got news of Faraday`s discoveries, he made no effort to claim
credit for his own work but often referred to Faraday`s discovery.
It was the change in the magnetic field which induced electricity
without a direct connection, not the value of the steady magnetic field
itself.
Same with antennas. A battery connected to an antenna sends no signal. A
varying field is required to produce a signal in an antenna.
Best regards, Richard Harrison, KB5WZI
|