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Getting the Best
from Your Clock Radio
028
P. Lay
wire to the underside of the bed or the back of the
wardrobe. For even more signal strength, fit instead a coax-
ial connector to the end of the wire and plug it into an aer-
ial socket. It is perfectly adequate to connect only to the
sheath and not to the central conductor. The connection
can alternatively be made capacitively using a capacitor
with a value of the order of a few pF. Indeed, soldering is
not necessary: the capacitive effect makes mechanical fix-
ing alone sufficient. If the aerial socket is near enough to
the clock radio, then the hook-up wire can be dispensed
with altogether and the connection made directly. This
method is particularly suitable when the radio is shielded
in a steel-reinforced concrete building.
Clock radios often give atrocious reception, even when prop-
erly tuned in. This is not surprising when you consider that
they usually only use a simple ferrite rod antenna. If no tele-
scopic aerial is provided, then there is normally a half metre
or so of wire poking out of the back of the radio, connected
to the tuned circuit: this usually improves matters somewhat.
Unfortunately, however, it is not always enough: but a
simple trick will let us improve the antenna’s gain. Fit a sin-
gle-pole connector to the end of the antenna wire, and to
the other part of the connector attach a length of insulated
hook-up wire. Using a couple of drawing pins attach the
(014055-1)
12/2001
Elektor Electronics
49
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