Belt Valley times., 1925-10-15

ltrallzsd Radio RsealVsr That Employs
Minimum Distortion Are Claimed.
mon rotor connecting to A minus ana
the two stators connecting respectively
TO the grid Of the second r. F. tube
(second from leftl. and the coil side
OF the grid condenser. C4. which Is
.O0025 MID. II will be noted that this
forces an apparent negative grid re
I'turn IN the detector stage. since there
can be but one grid return at the ends
OF the two secondaries. In fact, how
ever. the grid return Is slightly posi-.
tive in the detector stage. due TO the
manner OF connecting. the two-megohm
grid leak, R8 (grid post OF detector
tube socket to A minus). gat.s
II O00S5 MID variable eondenaers
are TO be used the coils would be made
as prescribed. except that the second
aries would have 81 turns of wire. In
stead OF 45. In this case the tap would
be at the twentieth turn.
The tap Is made nearer what Is
known as the grid end.
Proper Connection os Coils.
The aerial r. r. T. ls connected
with the aerial Joined to the begin.
ming |. e.. top OF the primary winding.
when the form is so placed that the
primary Is above the secondary. The
end Of the primary goes to ground.
Now connect the beginning OF the sec
Ondary. not to the fixed plates OF CT
and to grid. but to the negative A and
the rotor plates OF CT. Numerically.
as per diagram. connect TO serial.
2 TO ground. 3 10 minus A and 4 70
grid. This Is the inverse method OF
connection. the orthodox observance
OF poIarlties with the rect OF the
r. F. wiring, however. this system IL
not followed. The frst Interstage con-
pier (neutroformerl shown to the right
Of the first tube, IL connected with
the primary beginning f1) Joined TO
plate. the end OF the primary (2) going
to B plus amplifier voltage. Here the
beginning Of the secondary (S). which
adjoins the end Of the primary. con-
meets the grid (lnstead Of. as In the
previous case. to low potentially. and
the end OF the secondary TO negative
A. Thus the top. which Is Is turns
from the beginning Of the secondary.
ls nearer the terminal thereof 13) /
which connects to grid. The method |
just described is one wherein the pri-
mary connections are reversed. that /
Is. the polarities oppose at the adjoln-
Ing points e and 81. In neutr0dyne
this is correct.
The second interstage coupler Is con-
nected In the same manner as the pre-
.eding one (that is. unlike the aerial
roupler), except that (S) goes TO one
side OF the grid condenser, instead Of
to grid. The other side
If the grid condenser ls Joined to the
grid post Of the detector tube socket
-Four bypass condensers are used.
wo OF .0O1 mfd. each. across the sec.
OF the audlo transformers.
md two Of 002 mfd. from the end fB
illus amplIfier lead) Of the two inter-
tage coupling primaries 70 negative
l. to bypass the r. +. current around
he batteries.
A separate rheostat R2, actuates
he detector tube and is OF 20 ohns
assistance for the six-volt storage-bat-
tubes Ri controls the
wo amplifier tubes and is IS ohma.
battery switch. s. may be used TO
urn the set on and on as unit.
The coils should be mounted at q
7.8 degree angie. The neutraiixing
ondensera should be adjusted until
here Is no squealing.
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