New-York tribune., 1922-12-24
Regenerative
Set May Be
Very Simple
Circuit Described Which Is
Easy TO Construct and
Simple of Operation
With the Dry Cell Tube
Gives Remarkable Results
Some Operating Tips Given
Which Should BE Closely
Followed Out for Success


ceiver be made? That n a question
which I have been asked 20 often that
[ II Ia nv urpose 90 answer II in detail
this week. Az a matter Of fact, re-
renerative receiver can be made just
a. simple as non-rcgenerative set,
and when II &c taken into eonsidora-
ton that is range Is many times
greater, the advantages at once be-
come apparent.
In the hrst place. the simplest reEen-
erative receiver, which Is at tho same
time simple 20 control and operate,
can consist OF a vario-eoupler, vacuum
tube. telephones and batteries, plus
condensers. Il can be 80 wired up
that there will be but two major ad-
justments and one minor adjustment
while In certain localities the set can
be left AZ permanent adjustment
when the broRdcasting stations IN
range are all operating on The same
wave length.
The diagram which accompanies this
article win show az a glance how com
pact and simple this receiver can be
made. The aerial tuning circuit con-
sists Of q variable condenser and the
primary Of the vario-eouplef. In cases
where a full-sized aerial is impossible
II is better TO shunt the condenser
across the primary, rather than have y
in series In these cases practically All
Of the wave length tuning can be ae-
complished by means Of the condenser.
Tuning by Condenser
In other cases where the condenser
IL used IN series with the aerial, the
number Of turns on the variO-coupler
that arc actually in use can be con-
veniently left for both the $50 and 400
meter stations, and the tuning again
done By the condenser solely. A few
degrees turn on the condenser dial viii
be sufficient 90 diherentiate AS be-
tween the $50 and 400 meter station.
Where the condenser Is used In series
with the vario-coupler, there is very
. important point TO remember. IL IL
this: Do not, under any circumstances,
connect the lead 20 the grid Of the
vacuum tube in such manner that the
/ condenser 10 left in that circuit. The
| lead 20 the grid should be taken from
point between the condenser and top
/ Of the vario-eoupler, as shown In the
/ diagram.
There Is another Important point 20
/ be carefully followed in this circuit,
where Il will be observed a grid leak
\ Is shown shunted across the grid con
/ denser. Il Is the fact that the lead from
/ the ground side Of the aerial circuit
/ 70 the filament (Which completes the
grid cireuit) should be connected to
/ the positive side Of the A battery.
! The reason for this is that II attracts
| the excessive negative charge which
/ aecumulates on the grid and permits
this charge TO leak OF through tho high
resistance leak, so that the tube can
return to a normal operating eondi-
tiou.
Telephone Condenser Necessary
A bypass condenser is shown
shunted across the telephones and b
| battery. This can be the familiar fixed
telephone condenser, and its capacity
/ will range between .00i and OOPS, ac-
I cOrdlng 70 the tube used.
When this circuit has been COM
! pleted il will be seen that the con-
/ trolls will be the following: The yari-
able condenser for tuning 10 wave
| length; the rotor OF the vario-coupler
/ FOR volume, and the rheostat for clarity.
I The rotor 10 Joined in the plate cir
/ cult Of the vacuum tube In series with
the plate. the telephones and the B
battery. In this connection IL is very
| important 20 observe the connections
\ OF the rotor When the circuit is com
pleted IL may be that no reguEerative
action will be experienced, and con
/ sequently no increase IN the strength
| Of signals. The remedy for this con-
| dition ia 10 reverse the connections
on the rotor, placing the lead from the
/ telephones on the side where the plate
/ lead was before. This should give i'm
! mediate results.
Careful handling Of the rheostat will
/ clear up any distortion. The best way
/ 70 tune the set is as follows. Turn
/ the rheostst on practically full, or until
by touching the grid post with the
cate the set is in the oscillatory state.
Next vary the aerial tuning condenser
until a carrier wave Is heard.
How Wave Is Heard
This can be determined by the famil-
lar whistle which varies in pitch from
shrill 20 a deep low tone, 10 the point
where q dies out and then begins
again from the low pitch 10 the high
pitch. The correct adjustment Is be-
tween the two low pitched notes Now
turn the flament down until the clear
est signals are heard and then stop at
the point where they begin 10 decrease
In volume. A small final adjustment
with the rotor will bring In the high
est possible volume. The tuning should
be started with the rotor at q position
midway between maximum and mini
mum coupling.