Belt Valley times. [volume] (Armington, Mont.) 1894-1977, 1925-12-24

By GEORGE "a. MEYER
IN the News York herald-T ribuns.
How would you like TO build q four
tube set that would give volume al
most equal TO any nve-tube receiver
on the market7 II can be done. The
receiver about to be described may be
constructed without the use Of Tow
loss" parts or trick-wound coils II 10
an excellent receiver and as for vol
ume and clarity OF reception, nothing
more could be desired.
The circuit makes use Of q stage OF
radIo-frequency application which
seems to supply tremendous volume to
the detector tube.
Il Is the writer's opinion that
greater radio-frequency amplifcati0n
per stage can be obtained when the
circuit lie tuned In single circuit fash
ION; that Is, with a condenser con-
necfed In series with the antenna tun-
ing coll rather than across a coil hav-
ing an untuned primary winding In
past experience with receivers en-
ploying a stage Of tuned radlo-fre-
quency ahead of the detector results
have shown that greater application
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 radiO-frequency en-
pioying condensers shunted across sec
ondary coils and nontuned primaries.
II Is for this reason that this f0ur-tube
set viii 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 be homemade. Below is a
list Of the parts required to complete
the set
The Parts Needed.
One panel.
Two COOS variable condensers
One .00025 grid condenser with
One four megohm leak.
One l002 fixed condenser.
One tube inches In diameter, 4
inches long.
One tube 8 inches in diameter. Az
inches long.
One pair of audIo transformers
Seven binding posts.
-Four sockets.
Two single Jacks.
Two 20 ohm rhe0stats.
One 10 ohm rheOsfaf.
Two 4-lnch dials.
A careful selection Of the parts is
essential.
Designers OF some OF the highest
lass receiving sets have specified
iexible stranded copper wire for all
ilament and plate battery connections.
These leads are all punched together
md tle.A 20 keep them out OF the radio
frequency circuit. The wires running
o the sockets. binding posts and
heostats should be kept near the
dashboard OF the set. A receiver
Wired In this fashion win not be sub
ect 70 sQueals or high-pitched notes
'omm0n to . great many homemade
eta in which the ~A~ and ''B" battery
drcuif Ia ailowSd 20 traverse thu tun-
az circuit
Secondary Tuning Cell.
The secondary tuning coil which
eeds the detecfor tube should be
arefully made and wound tightly
vith No. % d. G. O. or d. q. q cop
eF magnet wire. There are three sep
rate windlnan on this coil, one for the
date Of the radio-freQuency tube. the
econdary and the plate coil OF tho &C.
sctor circuit The tube should Be
hFee anchem IN diameter and four and
ns-Aalf inches long Start about half
a inch from one end and wind nine
arms Of wire. being careful 10 pre-
ent the wire from coming unwound.
'msean each end Of this uEnmll winding |
heoueh snaaM holes made "a the tub /
az.
Then IN the reverse direction wind /
be secondary col with As turns Of I
Vire. Leave oneQuarter Of an inch '
etwesn the arme winding and the aeca /
ndaFy. Remember thu secondary coil 4,
] wound directly opposite 20 the nine I
arm coli. Both ends Of the secondary I
Vfnding nhould be fastened through (
oles ia the tubing Skip half inch !
nd wind nine more turns Of wire In /
he same direction as the 4S-turn wind 4
ag You now have completed the I
Oh. Il may be mounted in back Of the {
secondary tuning condenser and I
laced at right angles to the antenna Z
Ill. I
II tbs ansenns coil 10 mounted 40 V
shf frcu the base the coil with the :