The Washington herald., 1922-06-23
sine Herald :
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Questions and Answers.
Rece,v,nr Set Adju.tment..

the aerial be improved SO as to
give better results? Why won't
phone condenser across the phones
and a variable condenser across the.
secondary coil make the signals
louder? have tried all hook-ups,
and the inclosed seems to give
best results. Last night l used the
electric wire for an aerial as per
inclosed hook-up, and at s:lO
p. m. l heard someone sending.
couldn't read much of 1t because
of static. The signals were very
plain and loud: they must have
been sending on a very high wave
length. ! also got Arlington. and
Doubleday-Hill on it. too. Have
you any way of telling who
heard at $40 p. m. What is the
natural wave length of the inclosed
aerial. +. F. ID.
A. You have a great deal more
aerial wire than necessary for re-
ceiving. l suggest that you use
only one of the present wires, pref
erably without the combination Of
cage and straight wire aerial. Take
the lead-in from the exact center.
Other combinations are: Both S|~s,
lead-in from center; one wire, lead
in from end; cage aerial only, lead
in from center. With the space ami
wire available 1t will be worth
while to experiment with various
antenna connections and arrange
ments. Try these out on nights
when NOF, or other local station.
Is transmitting. Then the variable
condenser across the secondary coil
helps adjustment to resonance of
the closed to the aerial circuit.
whereas the phone condenser mere
~ holds the charges for successive
trains of oscillations through the
phones. Many things may cause
weak signals: The set may not be
tuned to resonance with the trans
mitter tboth aerial and secondary
circuits; detector not in proper
adjustment: or the coil contacts
making poor connections. Improper
adjustment is probably the answer
to your second question. The con-
denser arrangement you have is
not the one used in standard hook
ups for connection to a lighting
circuit. II you heard a station at
$40 p. m. on a high wave length
II may have been WVP. Fort Wood.
n. Y, who transmit on 1.450 meters.
The only way to obtain a correct
figure OF the fundamental wave
length of your antenna is by meas
urement with a wave meter. 1t
cannot be accurately calculat ted
from the dimensions of the aerial.
Receiver-Hook-up; Receiver Limi-
tatIons.
Q. have a two-slide tuning coil,
a crystal detector, a fixed conden-
ser. and a 2.2e0 ohm pair of phones
can hear WMU, NOF. wPM. WISH
very loud but can't hear The
Church of the Covenant (WOM).
Will a variable condenser enable me
to hear It? Which is best for a
crystal set 43 or a % plate con-
denser? w. r. Jr.
A. Send in your present diagram
2200 ohm phones should be satisfac-
tory. A variable condenser in the
aerial circuit is suggested. Either
condenser ordinarily will do. 1t de-
ponds on the capacity of your an
tenna.
variometer-Windin
Q. Please publish in your Radio
section the number Of turns and
sizes of wire to be used on each part
of variometer. (Rotor) and (Sta-
tors), Rotor measures Z inches in
diameter, inches wide, Stators
measure IL inches through, con-
vex measures AZ inches on one side
and ga inches on other side.
To be used with a vario coupler
with a radius of from $50 to zoo
| meters. F. r.
A. On both rotor and stator of the
variometer wind 30 or 40 turns OF
No. "a wire.
Regenerative Set.
Q. want to make a single tube
regenerative set. have socket
tube, and rheostat, also phones. bat
terry. both storage and r. What size
variable condenser should l get?
OBJ What should be the size OF
coupler tube?
Co What size wire in primary
and how many turns?
I'D On secondary?
(e) Is my hook-up correct
A. H. V.
A. For the condenser in aeria
circuit capacity .O01 is needed.
OBJ The primary coupler tube
inches; secondary. inches. Pur'
chase standard sizes.
(c) No. % wire on primary, %
turns per inch.
Cd No. "a wire on secondary. 3;
turns per inch. d. c. c..
Transmitter-Ranr
Q. What is the power and range
of NAA? Of WWX?
OBJ Is an aerial feet above Z
house 80 feet high as efficient a.
an aerial over the earth 80 feet in
height?
tc) Please send me information
how to construct a 650-meter vario.
coupler, size of coils. wire and
number of turns.
A. Questions of range cannot bt
answered definitely. Stations do not
transmit over the same distance or
successive schedules, due to a mum.
Der OF reasons. NAA is 100 kilowatt
station and is considered 1.50O-mile
range. WWX is 500 watts tele.
phone and 1000 watts c. w; IOC
miles is the approximate summer
daylight range.
(b) If the roof on which the aerial
is erected is grounded. an aerial 80
teet over an open space above
ground Is more efficient so far as
height alone is concerned.
tc) The rotor and stator may be
purchased and will give more eff.