The tricky part is matching/resonating the antenna. The signal is easy to
generate and amplify thereafter expertise is required
For
a given antenna with its given antenna capacity and radiation resistance you
will need a certain antenna current to radiate a certain power. To achieve this
antenna current you will need to apply a high voltage, depending on the
frequency and antenna capacity. You can generate this voltage in different ways.
My antenna capacity is in the order of 500 pF, which is relatively much,
relative to average amateur antennas. At 2970 Hz, i have to apply 11 kV to get
100 mA and 1.2 uW ERP.
Now, generating 11 kV (and more!) on 2970 Hz is
far from easy. Your transformer or coil or what ever arrangement has to
withstand that voltage. Ferrites tend to saturate at such low frequencies and
mains transformers are to lossy at this frequency, also their secondary winding
does not hold the combination of high voltage and 100 mA (and more! :-)
).
73, Stefan
Am 21.12.2016 13:42, schrieb Martin Evans:
Forgive me for asking what may be quite obvious to
many - but does this mean that if I spun a magnet at 8000rpm then I would
generate a 8kHz radio signal, identical in every way to an 8kHz signal
generated in a more conventional manner?
If so, it sounds a lot easier
than winding all that wire.....until the magnet flew apart
anyway!
Martin GW3UCJ Swansea.
ever heard of a "A MEchanical Based
Antenna" ?
Me neither until today ;-)
73, Rik ON7YD - OR7T
