I have been following the discussion on ferrite receiving antennas -
due to work pressures I am a few weeks behind in reading the mail.
The use of this type of antenna for LF amateur radio is not new. I
used it successfully as a portable antenna on the old 73kHz band
several years ago.
I used the existing winding (LItz) an ordinary long-wave broadcast
radio antenna. The rod was about 150mm long. The coil, tuned with a
large fixed C and a variable C, formed the drain load of a 2N3819,
with the output taken from the source. The selectivity was very high
indeed (essential to reduce the huge commercial signal on the 73kHz
band) and sensitivity was adequate to overcome the noise level of my
very sensitive Datong LF converter.
The interesting thing was that Peter, G3LDO, tried to replicate this
and had poorer results, perhaps indicating that not all long wave
radios had ferrite that worked at 73kHz.
Mike, G3XDV
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