The Ward County independent., 1922-11-30

is often used as a counterpoise and
connection is made with it by means
of number Of copper plates or an
interconnected network Of wires, sunk
into the ground at various places with
In the area underneath the antenna
These buried conductors should have
q low resistance aT(l should, be put
deep enough so that the earth around
them Is permanently moist. See Fig
ure Is for a counterpoise Of this type.
The Beverage antenna is one of the
most recent additions to the art of
short-wave radio reception. Due to it's
characteristics, it was used at Ar
drossan, Scotland, last December,
when % amateurs succeeded in bridg-
Ing the Atlantic with radio.
The Beverage antenna Is adapted to
the reception of signals on a single
predetermined wave length. 1t con-
sists Of one wire supported on 10 to
12-foot posts, this wire having
length of either one or two even wave
lengths If designed for 2O0-meter
reception, the wire will be either $500
or 1900 feet long.
Unlike the customary form of an
tenna, this wire is grounded at both
ends. At the far end, away from the
receiver, it is grounded through a nom
inductive resistance Of from 25O to 400
ohrns, and at the receiving end through
q variable inductance. In the case of
the receiver used at Ardrossan, five
stages Of radio frequency amplifica-
tion, q regenerative detector and two
stages Of audio frequency amplitica-
ton were used.
AS stated above, the Beverage an
tenna Is designed for reception Of a
single wave length depending on the
length of the antenna wire. If other
wave lengths are to be received, the
length of the wire must be changed
1t has been found that the signal
strength using LOO feet Of wire, IL
feet above the ground, Is approximate
ly the same as would be heard with a
single vertical antenna wire, 130 feet
In height. However, the Beverage an
tenna is highly directional, and on ac-
count of this fact interference from
directions other than those from which
one wishes to receive Is reduced to a
minimum. Also, due to the short dis
tance from the ground, statlc and at
mospherlc disturbances are almost
eliminated.
In general, it may be said that the
Beverage antenna is extremely we'll
adapted for the long distance recep-
ton Of signals from a given station
whose transmitting wave length Is
known.
Often by erecting an elaborate an
tenna system, the amateur does not
get as good results as would be OBJ
tanned from simple, well-located one.
The function Of an antenna is to cut
the electro-magn gnetic and electrO-static
components of the field radiated by
the transmtter, and have induced in
it an electro-motive force which will
cause a current to flow in the antenna
circuit.
The capacity and inductance Of the
receiving antenna plus small amount
OF Jumped inductance in the station to
furnish a drop to operate the receiv-
ing set directly or a magnetic field to
transfer energy to second oscillat-
ing circuit, should be equal to the nat
ural period Of the received r wave
Roughly, the natural period Of single
wire antenna is 1.22 times the length
of the antenna proper. plus the lead
in. This natural of the antenna sys-
tenn should be, as stated above, just
slightly less than the wave length on
which reception is desired. BY actual