The evening world., 1922-05-23
THE EVENING WORLDS
|RARH09PH0NEz
SERVICE COLUMN.

able. This feature Is called regenera-
tion and Is valuable because II adds TO
the sensitiveness OF the set enormously
II consists usually OF a coll whose eiec-
trical relation to the tuning coll can be
adjusted. This coll Is called the tickler
coil, or the intensity coil, or the regen-
Grafton coil. When this Is provided on
receiver. Il gives one more adjust
ment to be made. Consider a single cir
cult receiver using vacuum tube and
regeneration. We have three controls.
the wavelength tuning. the regenerative
coil, and tho flament rheostat. The
proper method OF procedure In opera
tion Is as follows. Set the filament TO
as near proper brilliancy as 1t 10 pos
sible to estimate. On many tubes thfs
point is easily found-the tickler coil
being set at zero during this adjustment
by increasing the brilliancy slowly
until a kissing sound !o heard in the
telephones, and then decreased just
enough to stop tho Kissing. The next
step Is to vary the wavelength control
over its range very slowly, listening
carefully for the desired signals, When
they are heard adjust the wavelength
control and the fllament control to best
results and then increase the regenera-
tive or tickler control until signals are
best, possibly slightly readjusting the
wavelength control which may be af-
fected by the change of the ticker. n
the tickler Is increased too far. tele-
phone signals will be spoiled, speech and
music sounding mushy instead Of being
clear. Always take pains not to in
crease tine ticker too far. because when
this IL done. the vacuum tube oscil-
lateH, or becomes Il small generator of
high frequency current and this cur
rent goes out on the aerial and causes
waves just like a sending station's, only
not as powerful. and other receiving
stations within a distance OF one or
two miles can hear Il and will be inter-
fered with by it. Whenever you hear
on your set, some whistling sound 8
which come and go, varying In pitch,
you may know that come receiving sta
tions near you are radiating In this way
because their ticklers are turned up too
| far. This is an excellent opportunity
for practicing the Golden Rule-remem-
Der that whenever your tickler Is in
| creased too far, you are causing to
other stations. the same interference
which they cause you. Every man on
| his own tickler guard.
The single circuit receiver with it's
few controls, is. quite simple to operate.
| and a little experience enables one Ia
| get results easily. This type OF receiver
|
| the two-circuit type; that is, 1t Is more
| likely to let through undesired signals
| with the desired ones, thereby interfer-
ing with the desired signals. On the
other hand. the two-circuit receiver es.
pecially II provided with regeneration
is much more difficult to adjust The
| major controls on u two-circuit receiver
are the serial circuit-calied primary
tuning, the secondary Circuit tuning
the coupling between these two, the
ticller and the tube hlament rheostat
III short there arc 1--WE controls to ad
just. The most important and mos
critical one Of these is the secondary
tuning. To pick UP signals. set tn,
coupling at or near maximum, she de
tector flanlent brilliancy properly, tn,
primary tuning control at or near Il.
lowest value, and tho tickler at or neal
its lowest value. Then very slowly var,
the secondary wave length control from