New-York tribune., 1922-03-19
H. R. c., East Orange. N. J..


phone, two telephone lacks ono y
-oi 'uoe socket and rhcostat and one
""P'i'ying transformer. can onerate
'he detector tube with great succcas
out am not able to use tho onc-sten
amplifcr.
An the diagram YOU include ;r
your letter you have the connections Of
inc ampliher circuit Joined UP incor
sectly. One side of the secondary of
your amplifying transformer should be
joined to the grid of the U. V. 2o1. and
the other side should be connected IN
the f'iament of that tube. Then the
negative side of your extra B battery
should be Joined to the positive side Of
the battery you use on the detector
tube and not to the secondary of the
amplifying transformer. Make these
changes and your amplifying bulb will
work all right
S. r. B, Princess Bay, S. l.:
Q-Can you tell me how to make
loading coil for my receiving set, which
works on the variometer principle and
which is supposed to be good up to 500
meters, so that l can hear WYCB,
which broadcasts on 1,45O meters?
A.-You can make such coil by
taking o tube inches long and 3h
inches in diameter and winding upon il
160 turns of No. "a D. S. c. wire Then
place the coil in series with your
aerial and your receiving apparatus.
This should bring in WYCB
Use l50-Foot Aerial
C. M. c.. Fultonville, N. Y:
Q.-Would a set made up Of
vacuum tube detector, a vario-coupler
and two variometers bring in the CON
ccrts from Newark and Pittsburgh
when operated in connection with an
aerial 200 feet long and rs feet high
The distance is about 200 miles.
A.-Yes, but the aerial should not
be longer than $50 feet altogether, in
Guiding lead-in. One variometer should
be in the grid circuit and the other in
the plate circuit.
Q.-Would such set operate q loud
speaker so that every one in the room
could hear whatever was being re-
ceived? If not, what additions would
be necessary for satisfactory reception
with loud speaker?
A.-No; it would be necessary 10 use
two stages Of audio frequency amplif-
cation in order to operate loud
speaker. At your distance from the
b1oadcasting station, however, I doubt
very much whether you could operate
a loud speaker without the further ad-
dtion of q power amplifier used in con-
junction with power-controllcd loud
speaker.
S. C. W, Dixondale, Va:
Q.-Which of the following combina-
tions is the best for tuning music 250
miles from the transmitting station
with vacuum tube detector: Cd Spider
web coils in any combination; (2)
! transformer or loose coupler with tick
Ter coil; (3) vario-couplcr with ticker
coil; (4) vario-coupler with two vari-
ometers. or (5) any Of the above with
vernier attachments on condensers?
A.-As music is chiefly broadcasted
on short waves the best of these would
he either a varo- coupler with ticker
coil or the vario-coupler with two
yariometer
Crystal Set Explained
I. K. Tcnany, n. j..
Q.-What is meant by primary and
secondary coils which was printed on
the diagram Of the crystal detector
published in The Tribune Radio?
A-Taken together. the two coils
form what is known as an oscillation
transformer. The primary coil is used
in the aerial circuit or primary oscilla
tion circuit. and the secondary coil is
used in the secondary oscillation cir
cult These two circuits must be in
resonance with each other, or in other
words, they must be attuned to each
other and to the incoming wave.
J. P, Springfield, Mass:
Q-My aerial wires are spaced two
feet apart Is that the correct width,
and will I get as good results as if
they were further apart? The aerial is
~ feet long.
lA.-For the purposes Of receiving an
aerial consisting OF single wire is
just as good as a two-wire aerial. and
does not bring in as much interference
from spark or telegraph stations.
would advise the use Of only one wire
in the aerial.
T. P, Brooklyn:
o.-I am having trouble with my
rheostat. One minute it is Jared and
cant hear anything. II put it past
certain point there is such a loud
roar in the telephones below that | do
not hear it at all What is the matter?
A.-Whcn you hear the jarring and
the roar YOU arc putting too muca
current through the flamcnt of the
vacuum tube. If you do not hear any
thing just below the point where it
"jars" you have not got your tuner
properly adjusted.
Aerial Is at Fault
n hovo q 1ooSo cOllDler 81 pair OF