The Ely miner. [volume] (Ely, Minn.) 1895-1986, 1926-05-14
BY HARRY j. MARX

Simplicity, efficiency and high quail
| ity, all combined, are the arguments
for the receiver described In this ar
ticle The circuit was first worked out
from simplicity end efficiency angle.
Trick features have been eliminated,
but every possible little development
for improvement In operation has been
| incorporated.
The circuit is shown in the illustra-
ton. Two stages of highly efficient
tuned radio frequency amplification, a
detector and two real stages of audio-
frequency amplifcstion certify to long
distance range and the best OF tone
quality in reception.
Three low-loss pickle bottle coils,
combined with high quality straight
line frequency condensers are the
major factors in selectivity. The os-
cillatiou control permits operation just
below the oscillation point of the tube
and insures maximum performance
with the best tone quality and mini
mum drain on the "B'' batteries.
One of the particular features of this
circuit Is the efficiency Of the eudio
stages, not only in the selection of
good transformers, but also in the
der to filter out all stray radio-fre-
quency currents and extraneous noises.
There remains much that is still to be
learned about the intelligent use of by
pass condensers.
&c" battery in the grid returns Of
factor in good audio application. The
loud speaker can be plugged in on
either the first or second stage jack
of the audio-frequency amplifier. The
last jack Is filament control for the
last tube, so there is no unnecessary
current consumption when only the
first stage is used.
Size Of Set.
The use of a 24-inch panel makes the
set compact one without unnecessary
crowding and interstage coupling,
which would be detrimental to salts
factory operation. There is no over
crowding in the panel layout and each
of the controls is so placed for con-
venience in tuning. The use of real
vernier dials makes tuning pleasure.
The controls are by no means COM
plicated or difficult to operate. A
rheostat is used for the detector tube,
another for the two radio-frequency
amplifier tubes, and a third for the
audio stages. The sockets are uni
versal and therefore permit the use
of either storage battery or dry cell
types of tubes A resilient spring ac-
ton In the socket design assures a
perfect contact and the elimination Of
microphonic noises by it's non-rigidity.
| Nine binding posts on a raised strip
are easily accessible and make bat
! terry connections simple matter.
Everything is easily assembled and
wiring is simple, rapid operation,
with none of those tricky inaccessible
/ connections which are the bane Of set
| constructors.
Apparatus Required.
The first question every fan asks
before deciding on the building of a
set Is "What parts will / need" The
following is the list of apparatus Sc
lected by the writer for use in his set :
1 panel, 3-16 by by "a inches.
1 Dashboard, % by by % inches.
8 Eastern classic coils, type EB.
8 National Equicycle SLF con-
densers, .O0O35 mid.
8 National variable velvet vernier
dials.
2 Multistage RID meloformers.
s Eby Tx cushion sockets.
8 Eby Ensign" binding posts.
1 binding post strip, 3-16 by y by
17A.
| 2 Carter limp" rheostat, IR-6. 6
ehms.
2 Carter "Imp" rheostat, IR-25, %
ohms.
1 Carter 'Tmp'' pilot switch.
Carter "Hold-Tite" jack. No. 104.
Carter "Hold-Tite" jack, No. 103.
/ Centralab radiohm, No. DOOM, 200,
GEO ohms.
| 1 Turn-it grid leak.
1 Turn-it panel control.
| 4 Dubilier condensers, type 6o6, %
MID.
Dubilier condenser, type GAO, .002
MID.
Dubilier grid condenser, type GAO
G, .0OO25 mid.
Is lengths Celatsite wire, No. Ia
(black, red, green, yellow. brown).