New-York tribune., 1922-11-26
First Aid for the Radio Fan
Suitable Loop for Use With Reflex Set;
Connecting "A Battery for WD-ll Tubes;
Should Super-Regenerato Be Shielded?
Loon Aerial on Reflex

Loop Aerial on Reflex
2uestion~-The reflex circuit interests mo
greatly. for am contemplating the con-
struc!ion of eeven-tuhe. cascade circuit
for loop reception combating of three
ssasss sas h,F' rSs ssteesor ssto tube and three
variable condenser only, but with a
potentiofneter In the circuit. The reaex
sroe ohisc hswsTer ssems ms, to aeeompsh the
tubes. and 1t would therefore be more
How VII Win '"s this eiscuit 0be' Be tuned for
loop reception.
3 Do you. advise inserting po,on-
tiometer, and II 80, where should it be
s. VIII this hoob-up with three tubes
give snfsieient volume on loop?
4. What size loop do you recommend IL
a loop Is satisfactory
6. when constructed for loop work can
II be readily transferred FOR antennae
rece ption FL. NJ. II.
Answer-1. The reflex system used
with loop will be tuned by means of
variable condenser shuated across
the loop.
2. A potentiometer can be used, and,
IL it Is, 1t should be placed across the
storage battery with lead from one
side Of the loop connected to its CEN
ter point, and the other side of the
loop connected TO the grid OF the first
tube.
8. II is, of course, always difficult to
state just exactly what any particular
receiver will do in any locality, and
especially in the case of this type of
receiver, which is still more or less in
condition of development. However,
1t should give sufficient volume On q
loop for loud speaker.
4. A three-Soot loop with six turns
20 hoJ
should be satisfactory.
5. II can easily be transferred for
antenn@ reception by simply adding a
vario-coupler. The variable condenser
that was used 10 tune the loop will be
across the secondary Of the vario-
coupler.
Parallel Battery Cells
Question: am trying an aeriotroh tube
on my two-variometer vario-coupler aet.
Should a. GRID leak be used with. this
the leak be7 IL a special transforraer
used With the new one and ne-haif volt
apls es .e tsoss @hs t,es would IN be
vois W tuse7 With my set as described
above. With no amplifcation and with
get all the local stations loud enough to
be heard two feet from the phones. Con
that II would be feasible to use q loop
aerial by adding two steps of audio FIRE,
anency anpiifcation to operate loud
Of ,hs o5n oan 10 the the
and ground posts? What would be the
effect OF grounding one side OF the loop?
Where are stations NOF and WDAP?--'
Answer--You can use the same grid
leak for the aeriotron as you did for
the u. V. 200. Generally speaking, the
W. o. ii tube is about equal in aver
age results TO the y. V. 200. With
regard to using the W. d. IL type tubes
as amplifiers: All that you will have
to do IL to place these tubes into the
regular sockets o? your set by means
Of adapters. The same transformers
will be used and the same conditions
observed throughout, with the excep-
tion that the one and one-half volt dry
stead of a six-volt storage battery.
Where you are using three Of these
W. D. Ii tubes in circuit, one
dry cell will not be sufficient to main
tain a steady condition in the fila
ment circuit, and consequently l would
suggest that three one and one-hatf
volt dry cells be used. In this case,
however, very careful attention must
be paid to the manner in which the
three dry cells are connected together.
Otherwise you will burn out the fila
ment Of the tubes. All of the three
positive binding posts should be con-
nectsd together and all of the three
negative binding posts should also be
connected together. Then lead from
the positive and another one from the
negative will be Joined to your set in
the regular way. You cannot get loud
speaking results with loop aerial on
an ordinary reeenerative receiver un-
less you are extremely close to the
broadcasting station. Grounding one
side Of the loop will help little, but
with a regenerative receiver would
advise an aerial by all means. NOE
is the naval station located at Anacos-
tia, Washington, D. c., and WDAP is
the Midwest Radio Central, Inc, sta
tion at Chicago.