The Washington herald., 1922-04-25
Questions and Answers
Detail. Of Hosk-Up.

Q. am making a small cabine'
amplifying set. Can two variabi,
condelnsers, a small fixed condenser
be used in circuit with a variom
eter and a variocoupler employing
two bulbs, one for the detector and
the other for the amplifier? A rhe'
ostat and grid leak condenser ar,
included. How far will this Sc
receive? What will its wave Length
be? Will you publish a hook-up'
b. Can two spark coils, one a l.
inch coil, the other a h-inch coil
be used together for sending? Whai
would be its range, and how many
dry cells would be required to op-
crate II?
c. who are sxG. sBoF. sxz. ant
KDIJ?
d. What voltage storage batter,
Is needed in Part a? b. L. w.
A. Fig. A or B Of hook-up pub
RTished in The Herald OF April
Range and wave length will depend
on your operation and adjustment
Fifty miles is an approximate hg'
ure.
b. Yes; but 1t IS not the best
Use a vibrator IL possible. Ap'
proximately twenty-five miles. L
is always best to send in q hook
up of the set you are using or pro-
pose to use. Data given is Away,
for correct hook-ups and norma
working conditions.
The calls you ask for are moi
listed in the call books in general
circulation at the present time
Possibly they are new stations re.
Gently assigned call letters. The
first three calls would be those OF
amateurs in this district. RDIJ i,
the s. s. Cuprum, operating on gen.
eral public service 600 meters a,
all hours.
q. Six volts.
Alternate AeriaIs.
Q. Why are there a number o.
aerials between abe masts and a
different angles On battleships?
G. X.
A A battleship operates at diff
ferent wavelengths and with vary
ing transmitting power 1t Is ais,
equipped with radiophone. Aerial
OF different dimensions are used t,
AFFORD the maximum efficiency 70
the service desired. For radiophon,
transmission on low power, tw,
aerial wires the length between
masts OF the ship are SUFFICIENT
whereas for long wave and higl
power transmission greater radia
tion IL desired. hence longer anC
several-wire Re:ials are used. Ais
antennas which are in part hori
zontal and in part inclined are fol
some purposes more eficient thar
those stretched in one direction
only. The chief reason for seve=a
aerials aboard a battleship is tn,
possibility of having some wires
even a whole aerial shot away dur
ing battle. Alternate aerials couIt
then keep the ship in communica
tion with other units.
Circuits I'm Resonance.
Q. l have read about keeping tn,
parts OF my receiving circuit Il
resonance with each other. wha
does this mean? @. XXI
A. The term resonance is use,
when speaking OF two osciIlato-,
circuits, where there 10 a mutua
transfer Of energy. Thus you woult
brlhg the secondary of your receiv
ing set into resonance with the in
coming radio waves by varying ca
pacity and inductance.
Energy from the primary circuI
Is being transferred to the sec
ondary circuit. To receive tn,
strongest signals and effect tn,
finest adjustment these two circuit,
must oscillate In such manner
that the transfer OF energy from
the primary to the secondary I,
maximum. II the circuits are no
in resonance the tubes of the sec
ondary circuit may be damaged du,
to the difference in freuuencies o,
the two circuits. Much this sam,
effect is present in the phonograp nj
when a high note causes the re
producer to vibrate beyond IL,
limit. The singers voice and tn,
vibration of the reproducer dIa
phragm are not in resonance a,
that frequency.
Filter system Stops Noise.
Q. II a radiophone is so sensitiy,
to noise and disturbances when 4,
a home as a man told me who jus
installed our set, how can 1t be use,
FOR ship service. especially on small
boats or on boats with powerful
and noisy machinery?
A. The set itself aboard such ;
ship is placed in the radio room
protected as much as possible from
disturbance. The engine and othe
noises are partly eliminated by RI,
filter system. This is a balancin,
system between inductance coil
and. condensers so that the bacl
energy from the inductance coil
passes through the condensers. TIL,
whole arrangement is very care
fully constructed and eliminate
nearly all noise.
Grid Leak and ,nden.~r.
Q. What are the uses of the xrI,
condenser and the grid leaLs