The Challis messenger. (Challis, Idaho) 1912-current, 1925-12-23
BY GEORGE M. MEYER,
In the New York Herald Tribune.

W Tie new YORK f1Srdlo- ripune.
How would you like to build four
tube set that would give volume al.
most equal to any five-tube receiver
on the market? 1t can be done. The
receiver about to be described may be
constructed without the use OF slow
loss parts or trick-wound coils. 1t is
an excellent receiver and as for vol
ume and clarity Of reception. nothing
more could be desired.
The circuit makes use of stage of
radlo-frequency amplification which
seems 10 supply tremendous volume to
the detector tube.
1t is the writer's opinion that
greater radio-frequency amplIfcation
per stage can be obtained when the
circuit is tuned in single circuit fash
ion that Is, with condenser con-
nected In series with the antenna tun-
Ing coil rsther than across coil hav-
Ing an uncuued primary winding. In
past experience with receivers en-
ploying stage Of tuned radio-fre-
quency ahead OF the detector results
have shown that greater ampllficatfon
OF radio-frequency currents is possible
with the series circuit. In fact this
type OF circuit has been known to
produce as much application as two |
stages OF tuned rado-frequency en-
ploying condensers shunted across sec
ondary coils and nontuned primaries.
II is Tor this reason that this four-tube
set Will produce as much volume and
receive as much DIX as some five-tube
tuned radio-frequency receivers
Special couplers or coils are not nee
essary. as the two coils In this re-
ceiver may De homemade. Below is
list of the parts required to complete
the set:
The Parts Needed.
One panel.
Two .00O5 variable condensers
One .OO025 grid condenser with !
mounting.
one four megohm leak. )
One OO2 fixed condenser
One tube inches In dtamater :
inches long. ~
one tube 3 inches In diameter. Az
inches long
One pair of audio transformers.
Seven binding, posts.
Four sockets.
Two single Jacks.
Two 20 ohm rheostats. ;,
One 10 ohm rheostat. - =,
Two 4-lnch dials. :,
A careful selection of the parts "a :,
essential. q
designers OF some of the highest i,
'lass receiving sets have specified -
flexible stranded copper wire for all =,
lament and plate battery connections n,
'iese leads are all punched together =.
md tied to keep them out OF the radio 49,
frequency circuit. The wires running :"
the sockets, binding posts and :.
neosfats should be kept near the -
aseboard OF the set. A receiver -, ~
'ired In this fashion will not be SUBJ -
oct to squeaIs or hIgh-pitched notes u
ommon to great many homemade -
cts In which the "A" and "B" battery az
Ircuit is allowed to traverse the tun- va
e circuit COZ
Secondary Tuning Coil. s''
The secondary tuning coll which w
'eds the detector tube should he ue'
'refully made and wound tightly pa'
18th No "a ID. G. g. or ID. s. G. COP sos
n mappet wire Thor,. ~ - up str
ate windings on this coll, one for the
ate OF tho rodIo-sraouaro,, 80 n
ao =. '"e ,"uio-irequency tube the
u'y anu une pate con or the de- 70
ine TUBE should be que
.eo ,ncnes III a'aneter and four and as
To- s 'o"s. o'art ABOUT haif SOC
o o"e emu ana WIND nine S''a
-. ~ De"s careiui 10 pre-
go I'm .on'ns uhwound. IN
$3.50, ."u ~ '''is small winding the
'e' 'n"ue III tne tub- anu
rho T., 49, her
. sscoraarv 81, ~, '.,uon wihu ical
re. Leave onaorartar ., Turns u ona ,