Hello Walter, Tracey, Alan,
It happens to be that I own a battery powered SPM-3 and I have often used a
(mini) whip without any connection to ground. As a whip is a monopole some
counterpoise is necessary. I gathered that this happened by capacitive
coupling between the case of the SPM-3 and earth (the real thing). As the
(mini) whips capacitance is small, the value of the capacitor to earth need
not be very large.
This was confirmed when I lifted the SPM-3 from the plastic garden table and
put it on the ground: the signal level increased. If I remember correct it
was in the order of 1 dB or so.
Regarding Tracey's suggestion, when the weather is a bit more like it, I
will hoist the contraption up a fiberglass pole. The only problem is that
the capacitance of the SPM-3 to ground will be substantial larger than from
the (mini) whip.
Best regards,
Roelof Bakker, pa0rdt
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