Wausau pilot. [volume] (Wausau, Wis.) 1896-1940, 1922-12-14
RADIO COLUMN
ATHENA


to be erected is the first problem that
confronts the purchaser of builder OF
a radio receiving set. The idea is
quite prevalent that the larger the
antenna the better the results will
be. Or. on the other hand, some
have the idea that anything from a
bed spring to tea kettle will do.
Too large an antenna is handi-
can for receiving. 1t is true that
200-ft. antenna will pick up more en-
ergy than one half as long, but this
is where the difficulty comes in.
With a large antenna it will be found
that interference is difficult to tune
out. Broadcasting stations today are
divided into two classes, one using
$50 meter wave and the other 400
meter wave. With large antenna
it will often be found difficult to tune
out the 400 meter wave when it is
desired to receive on the other, or
vice versa.
The ideal antenna and the one CIV
ing the best results on the reception
of broadcast programs is single
wire 100 feet long and at least thirty
feet high. The height of an antenna
is measured at it's middle point; the
height of a slanting antenna may be
determined by measuring from the
middle of it to the ground. The bed
spring. wash boiler or tin roof anten-
ma may be dismissed without serious
consideration 1t is only useful in
case of emergency or as an expert
ment, and then only when a great
deal of amplification is available. The
amateur will find that the 100-ft. sin
I'll xu;,o ontcnna iS hest of all.
It has been estimated that there are
1.5OO, 900 radio receiving sets in homes
throughout the United States. Pitts
burg is said to have radio set in one
home out of every six and Detroit ap-
proximately $4,000 receiving sets.
These were furnished with programs
from 553 broadcasting stations re-
ported by the government in opera
ton on the first of November. OF
these 553 stations, nineteen are class
B stations operating on 400 meters.
DAYLIGHT VS.. NIGHT
Operators experimenting with their
set will find condition that may puz-
zle them as it has many and that is
that signals are much stronger at
night than they are during the day,
and that stations which are received
with ease in the evening cannot be
heard at all in the daytime. Cues
lions are often asked about the cause
of this but no satisfactory explana-
ton has ever been given in spite of
many experiments carried out to
study this phenomenon. Eric r. Mil
Ter, meteorological of the weather bu-
reau at the University of Wisconsin,
some time ago gave his conclusions in
an article sent out by radio from the
university station. He said:
electromagnetic waves are propa-
gated in non-conductors or dielec-
tries, as they are called, but are re-
fiected or absorbed by conductors of
electricity While air and other gases
are non-conductors, they become con-
Quoting in the presence of flame
and when the rays of radium, X-rays
and ultraviolet light shine into them
the gas is said to be ionized.
1.-THE earths atmosphere is nowhere
a perfect non-conductor, but the layer
80 or 40 miles thick, Immediately adj
jacent to the earths surface is be-
lieved to be the stratum in which ra-
dio waves are transmitted. Above
suns rays causes a rapid increase of
conductivity with altitude SO that
there is bounding surface called the
Heaviside layer, concentric with the
earth's surface.
During the day the dielectric layer
adjacent to the earth is also penetrat-
ed ard ionized to some extent by
short-w2ve radiation from the sun,
increasing it's conductivity, and de-
creasing its efficiency for the trans
mission of electromagnetic waves.
After sunset the ionizing effect of the
sunlight diminishes and the range of
transmission of wireless signals
lengthens.
when the sunrise and sunset line
is between two stations, transmission
of signals is almost impossible. II
seems that the boundary between the
illuminated and shaded parts of the
atmosphere in the twilight zone acts
either as a reflector or as an absorber
of radio waves
This explanation sounds logical but
is not generally accepted. Much the
orizing has been done but no definite
conclusion has been reached. Pro-
lessor George w Pierce of Harvard
made to determine the cause of weak
er signals at night, and decided that
the increased conductivity of the air
in the daytime could not be the cause.
1t was found that signals from a
shore station to ship could be heard
100 miles at night and only 600 miles
in the daytime. The increased con-
ductivity of the air by day over that
by night was calculated, and the diff
ference was found to be too small to
produce the effect observed. 1t was
found that in order to decrease the
night range to one-third as shown,
the air would have be be 100000 times
as conductive as it is. This difference
in transmission range is not noticed
at short distances and is much less
ened by the use of very long wave
lengths.
WAUPACA STATION
The new department of markets
broadcasting station at Waupaca,