The Washington herald., 1922-10-01

pended In 'front.' OF me.
Hopper's mobile voice sank to
sorrowful note as he spoke of the
difficulty of delivering this famous
baseball recitation without the en-
phatic Gesticulations which have
noted that the panel is carefully
shielded with aluminium.
"A shelf is held to the trout panel
by means of brackets. \ shelf sup
ports the three tube sockets, the
filter circuit. and the coil L5. while
beneath the shelf are suspended the
audio-frequency amplifying trans
former Tr and the coil LA whicn
acts as radio-frequency choke.
Leads with clips attached are used
to make contact with the grid bat
teries. The binding posts for the
iilament and plate batteries are
mounted at the back of the shelf.
referring to the front of the
receiver, the loop plugs in the jack
are on the left and the loud speaker
on the right. The lower dial on
the left should control the con-
denser across the loop and there
iOre changes the wave-length of
the circuit. The dial Immediately
above this controls vhe feed back
Of the first tube as it varies the
position of the secondary of the
variO-coupler. The potentiometer -
controlled by the small knob at the
top center of the panel.
All that Are Needed.
These three controls are prac-
IiCally all that are required to tune
this receiver, after the proper pO-
sitiOns have been found for the
other two dials controlling the oscil-
Iation and the frequency of oscilla-
tiOn of the second tube. The grid.
plate and filament batteries are con-
nected to the back Of the receiver.
leads being brought through the
cabinet with clips attached.
Most of the apparatus employed
in this receiver is quite familiar.
a.. cS and vario-coupler are now OBJ
.,;hle from radio dealers.
Operating the Receiver.
When the flaments are lit hign
pI,ched whistle should be heard from
,n, loud speaker. This whistle indi
Gates that the second tube is oscil-
,atIng. If the whistle is not present
the grid battery B3. the pOtentiO
meter and the condenser ca should
lie varied to produce oscillation"
says EadIo News.
When the whistle is obtained.
the feed back coil L. and the con-
dencer Cl are varied to produce
oscillat on in the first tube. This
point of oscillation will be easily
recognized by the usual tests for
oscillation.
wv tn the first and second tubes
oscillatinG, if the circuit has been
correctly wired. a certain unmis-
taxable effect will be not ced. If
any of the variable elements Of
the circuit are changed. a series Of
heterodynes of harmonics should
be heard. This indicates that the
g rcuit is properly connected. al
though these harmonics will not
be heard after the circuit is ad-
Justed.
Rest of Tuning Easy.
After this state has been reached.
the rest Of the tuning is easy.
The wavc-lenSth OF the stat on TO
he received is tuned by the con-
dSnSer across the loop and by
tapping the number Of turns on the
loop itself. Voice or music should
hr audible. Tnc two dials at the
rI-ht Of tho recc Ner should then
be varied to obtain the maximum
ampiificstiou Usually these con-
JCrScrS need to h" at about their
wa Nimum capacity. \ Cond tiOn
viii bC easily found where the
histICs "G the harm"nics are no
longer audible and the speech or
MUSIC j. received clearly. Final
tuning with tho grid battery and
p"tcntiomCtcr will find the crit cal
point
No matter how explicit the :n-
StructiOns may be, undoubtedly the
ne It method Of operating the super
rcecnerating receiver is learned by
practice After a little experience II
IS not difficult to find the different
effects and learn to recognize the
sounds which accompany them.
The receiver is well worth con-
sructinE. 1t does not cost much
more than an ordinary reGenerative
receiver and there is no comparison
in the results.
An aerial should not be employ I'd
with one of these receivers. For Cne
reason. it is hardly necessary. as a
loop is all that is required to re
Ccivc. For another reason, il these
receivers become common they will
interfere considerably with each
other if they are used in connection
with acrials. II a super-regener-
ative receiver becomes out of adjust
ment it radiates strongly. Thi effect
is not so noticeable on a loop which
will not radiate any great distance.