The Ely miner. [volume] (Ely, Minn.) 1895-1986, 1925-04-10
illustrated includes
ndenser.
This
BILE Success

Among the great army of radio fans
In the world today there are hundreds
still using cryStal-type receivers.
There is reason for this. A good
crystal is perfect in reproduction of
voice and music.
The crystal set requires no batteries
and therefore has no upkeep expense.
For one who seeks reception over
short distances of about fifty miles a
set of this kind is more than satisfac-
tory. There are many fans owning
multitude receivers who still keep
their crystal sets for local reception.
The clear natural tones are pleasant
change from the loud speaker. No
harm will result if you take a little
snOoZe, for there are no batteries to
run down and no tubes to turn out.
SeIectivity Limited.
The principal objection to the crys-
tai set is the lack of selectivity. 1t
lacks the power of the tube receiver
to cut one station in and another out
II necessary tuning devices are used
that are essential to make a crystal
set selective, the resistance created
seriously impairs the volume and
shortens the range. The energy used
In a radio set Is enthusiastically small
If all that is accumulated on the aver
age antenna in a years time were col
lected into one charge 1t would not be
sufficient to light a fiashlight bulb. 1t
is so small there are no instruments
delicate enough to accurately measure
1t. 1t is therefore necessary to con-
serve all the energy possible.
There are several methods that may
be used to make a crystal set selec-
tive. These are loose coupling of the
tuning inductances, the use of several
variable condensers, or adding wave
trap arrangement. Aside from being
added expense these methods are not
wholly efficient. One result is obtained
through the sacrifice of another.
Characteristics Of Set.
The set shown is simple arrange
ment Of variometer and variable
condenser. This circuit, although not
basically different from many others,
has enjoyed remarkable success. 1t has
good selectivity, good volume, and an
exceptional receiving range. In some
cases it has been possible to operate
a loud speaker on nearby stations and
distances of five 20 seven hundred
miles have been heard on the phones.
The results are all that could be ex-
pected from a crystal receiver.
The reason for this is 4 has both
inductiye and capacity tuning and
practically no losses. All taps and
sliders characteristic of most crystal
sets have been abolished and work
manship and materials of vacuum
tube quality have been used through
out. 1t is tie usual practice to build
a crystal set as cheaply as possible.
This accounts for at least four-fifths
Of the trouble experienced with crys-
tai sets and is responsible for the linn
itations put on sets Of this type. One
wouldn't expect tube set to work
efficiently with a crude tapped coli
and Junk" parts, so it is hardly log
ical to expect it of crystal set. Be
fore the days Of tube receivers the
amateurs built crystal sets, using good
apparatus, and got results that would
make many owners of tube sets today
envious.
Antenna, Ground Parts.
The antenna should be of the single
wire type about 125 feet long. It
should be run in perfectly straight