Evening star., 1923-05-27
BY PAUL GRIGGS.

IT we replace a crystal detector In
receiver with tube detector we
Invariably obtain stronger or louder
signals from passing radio waves.
We are also enabled to hear the pro-
Grams broadcast by distant stations
located too far away to be heard with
a crystal.
If we associate one or more am
plifier tubes with the detector tube
we obtain signals of still greater
strength. We then can hear pro-
grams broadcast by stations situated
perhaps 1000 miles away; possibly
1000 or more miles away.
We say that the tube detector is
more Sensitive" to passing broadcast
waves with which our antenna and
receiver circuits are adjusted to res
onance" than is the crystal detector.
and that the amplitier tube or tubes
increase the sensitivity of the de-
tector tube.
The logical inference is that the
detector tube abSorbs or causes to be
absorbed. relatively more of the elec-
tro-magnetic energy from. passing
radio waves than the crystal is cap
able of absorbing and that the addi-
tional amplifier tubes. when used.
cause still more energy to be alb
sorbed from the passing waves.
From what other possible energy
source could the stronger or louder
speech and music come?
We quite naturally assume that the
signal strength must all be extracted
from the passing radio waves: that
the full volume of the incoming
speech and music is all picked out of
the air."
Power of Antenna System.
AS a matter of fact. however.
neither the crystal detector nor the
tube detector nor the tube amplifier
have anything whatever to do with
the amount of energy extracted or
absorbed from passing ether or radio
waves. 1t is our antenna or collector
system, and that alone. which ex-
tracts or absorbs electro magnetic
energy from passing waves, and the
same amount of energy IS absorbed
from passing waves entirely regard
less of whether crystal or one or
more tubes are employed in the re-
ceiver
A properly designed low-resistance
receiving antenna system will absorb
more electromagnetic speech and
music energy from passing waves
than will an Improperly designed
hlgh-resiStance antenna system.
The antenna circuit transfers it's
energy to the receiver circuits and
an efficient antenna will transfer
more energy to the receiver than will
an inefficient antenna But this con-
dttion applies regardless of whether
we employ crystal detector in our
receiver, or single tube detector or
tube detector associated with one
or more amplifier tubes.
1t is clear. then, that when we en-
pioy tubes in our receivers there must
be available some local auxiliary
power which produces the equivalents
OF human speech, music and other
sounds. and that this local power is
lacking when we employ crystal
This is actually the case. The local
auxiliary power is in the tubes within
our receivers.
The detector tube in our receivers
with it's circuits and batteries, con-
stitutes local miniature electric
power plant.
Likewise. the amplifier tube consti-
tutes not only a miniature electric
power plant within itself but when
functioning as an amplifier it COM
prises a miniature transmitting sta
tion within our receivers.
1t is not to be wondered at, then
that We obtain loud signals and can
hear distant stations when we employ
tubes, especially amplifier tubes
Crystal Detector Minus Energy.
In itself absolutely no energy or
power whatsoever 1t is entirely de-
pendent for its functioning on the
energy of the incoming signal oscil-
tattons and its manner of functionine
actually wastes at least half of the
incoming signal energy by suppress
ing every other energy alienation of
the incoming wave
The tube detector. on the other
hand, not only causes virtually all of
the incoming signal energy to be
utilized for producing sound in the
telephones, but it also adds it's own
electrical energy to that of the in
coming signals, thereby strengthen
ing the signals, as described in my
article of May 49,
Obviously, therefore. we should al
ways obtain signals of at least double
the strength for the same distance,
and we should be able to hear stations
at least twice the distance when we