New-York tribune., 1922-11-26

qu'te as Snarp as the YarIo-c Coupler
variometer. type or the honeyconlb
coil type. The latter are both about
on par, with the former having a
slight edge" In all-around efficiency.
with regard to the honeyconib circuit:
The sizes OF the coils used in the
primary and secondary will depend q
great deal upon the length Of the
aerial and other conditions of the set,
but for the $50 to 400-meter stations
II will be something like 36 for the
primary, so for the secondary and rs
for The ticker. You will understand,
of course, that these sized coils are
by no means exact, and that you will
have to find out which q /, the best
through experiment after you have xot
your aerial erected.
Dry Cell Tube Ampli1er
ns 9eestion-Are there any employing
bulos made that operate on dry cell, and
II 80 do they work we'll as the amplfy-
ing tube that operates OH a etorage bat
terry 7--F B.
Answer-The aeriotron w. D. IL tube
will act very satisfactorily as an ampli-
fier, and is practically equal to the u.
V. 201, provided G battery is used
to maintain negative bias on the grid
Of each of the amplifying tubes. In
this manner 100 volts can be placed In
the plate circuit Of these dry cell tubes,
provided negative bias of three volts
is placed on the grid.
Honeycomb Coil as Tickler
auestion-~rs a rsgenerative honeycomb
to handle in tuning with IT'S two condensers
and two movable eoilsf How does IL COM
pare in facility Of control as we'll as Ia re-
a ri fAr way
meter hook-up? What size honeycoms,
coils would you recommend for the hook
be represented as shown In sketch Once
the switches are set ho uses only the con-
denser and tiokler II 10 the simplest
It for tuning ability and sharpness p
Answer. The secondary Of the
vario-coupler can be used as ticker
COIL. thus making such a circuit a
single circuit regenerative set. 3. A
double sliding tuning coil. Of course.
can be placed in series with The pri-
mary Of the vario-coupler, and allow
you to tune 20 the $50 and 400 meter
stations, but it would greatly interfere
with the efficiency Of your receiver at
those wave lengths.
Cutting Out Interference
0ueaticn--Up until recently we have
good reception and good selectivity Srora
stations as near se Newark and ae far
away az WHB, Kansas City, No, Recently
tuning any one station without inter
ference from others, resulting In our en-
deavoring to distinguish one out of two
or three by means Of our ears alone,
which, as you know, is rather difficult and
not very entertaining. For instance. Last
evening We could not separate VIZ.
WAX, WHAs and KDKA srom one
We are using an MR6 set with duo
lateral, honeycornb cosle: primary DL 20.
secondary DL so and ticker DI. a6, two
detector. Aerial is two-w!re. eaoh i3o
feet long, space 2 feet 10 inches apart
lead in ls 40 feat long and ground wire
b battery on the ampiifier tubes.
/. Would double wire aerial, 100 feet
long. give greater or less~ intensity, greater
or leSs seiectivity?
2. In case single wire aerial is better,
is there any harm in leaving the other
wire suspended in the air attached to the
spreaders and simply dtsconnecting It from
8. Would any other combination OF
coils give greater selecttv.ty?
4. Can you suggest any system Of aerial
with cur DeForest set so give greater
selectiy!ty?
We are situated here IN the northeast
corner OF FennSSlVanIa, dDout lWSlty-iiVe
miles from Birg ghamton, N. Y. We are
not especially Interested in receiving from
long distances but prefer to be able to
pick out stations clearly and without
or 500 inliea.--F. M. W.
Answer-You are apparently situ-
ated in district that is exception
ally good for radio reception, and con-
what normally should be
an advantage is really disadvantage
to you.
There is practically only one. sug-
gestion that j can make and it is the
following: Pick out the one station
that you desire to listen TO most and
then erect single wire aerial sew
twenty feet above the ground, and
point. this aerial in the direction of
that particular station, taking the
lead-in from the end nearest to him.
The iead-in should be as short as pos
siblc. This will give you maximum
directional results from that particu-
lar station. You could then use your
other aerial for listening TO distant
stations st any time you desire. When
you are not using it would suggest
that it be grounded.
In reply to your specific questions:
|. A single wire aerial gives better
tensity so far as receiving is con-
cerned.
Q. If you leave the second wire up,
try grounding it.
8. would suggest that you try
other combinations of honeyconsb
coils, in which case you will find it
necessary to reduce the amount Of ca
pacity in the condensers used in cou-
junction with the primary and sec
ondary coils.
4. These are about the best sugges-
tions that | can make and would not
advise using any additional apparatus.