The Challis messenger. (Challis, Idaho) 1912-current, 1924-11-05
BY FRANCIS H. ARMSTRONG

BY FRANCIS II. ARMSTRONG
One of the problems troubling many
radio fans at the present time is the
adjustment of their sets to cover the
higher wave lengths, especially of 492
and 526 meters. One method that may
be applied to most receivers in pres
ent day use, and particularly those Of
the two variometer and. variocoupler
type, is by the addition of instruments
called condensers. Where such load
ing of capacity is resorted to great
care must be exercised in securing re-
generation over the wave length bands
desired.
Most receiving sets embodying radio
frequency will remain just as they
are. These instruments are governed
by the range of transformers included
In the construction of the set, and
the general practice of most manufac-
turers has been to design their radio
frequency transformers to cover
wave length range of from 300 to $50
meters. There is no question regard
ing most Of the transformers made
today, as the majority run as high as
the new wave length of 526 meters.
In some cases where loop aerial Is
employed in conjunction with radio
frequency set more turns of wire on
the loop may have to be added in or
der to secure sufficient added induc-
lance in this part of the circuit to
reach the wave desired. The reason
for this Is that the loop acts in this
case as a tuning inductance. Should
the loop aerial be deficient In its in
ductance value, then there Is no resi-
dent point to work on for the higher
wave lengths. Better service may be
had If the original loop is supplied
with a sufficient number of turns on
its frame, which are then varied by
means of a suitable tapping or
switching arrangement.
Loading Three-circuit Tuner.
Under this type of Regeneration
comes the well-known two variometer
and varicoupler circuit This type of
apparatus has become the prize re-
ceiver of many a radio fan, since it |
contains the elements which give |
set selectivity, but since some new |
stations were injected into the ether |
1t seems that most of the variometer |
sets fall short of bringing in con-
certs on the longer waves. With this
set an arrangement can be made to Sc
cure shorter waves with their maxi
mum signal strength just as efficient
ly as when using the longer wave
length bands.
This arrangement consists of en-
ploying double pole, double throw
switch, or by the use Of an antica-
pacity switch. The first arrangement
would be the better Of the two for
the beginner or novice, since 1t ap-
pears to be much simpler. In the ac-
diagram (Figure y one
may get an idea how the double pole.
double throw switching arrangement
Is employed. The wave lengths de-
pend entirely upon the position of the
switching device.
In Figures 1 and the condensers
are represented by c.. These con-
densers may be made at home OF they
can be purchased at any radio shop
at the option of the builder If pur-
chased the fixed type condenser Is
to be preferred. In shopping around
The fan will run into various types of
liked condensers, many of them con-
,isting of paper and tinfoll. This type
If condenser should not be considered,
Is its capacity is not uniform.
In recent tests some of these pa {
,er condensers gave no fixed reading
capacities varied any
where from OOO2 to O01 MID. merely
oy pressing the condenser together
With the fingers. Due to their loose v
construction. moisture creeps in and 8
aries the capacity to the same de- b
rec Of inaccuracy. What the fan 7
hould buy Is a condenser constructed o