New-York tribune., 1922-10-01
Eliminating Radiation

! Question--Is a different circuit used fol
the elimination of radiation? From con-
| Vcrsaton had with an electrical engineer
understood that some legislation had beer
enacted prohibiting the use of any, except
the particular circuit which would no,
cause radiation from the antenna. From
what you say I take 1t that the radiation
has been caused from the single circuit
receivers am Of the opinion that the
average amateur handling q two circuit
tuner has great variety Of howls and
squeaks. Do these noises not radiate suf-
ficiently to cause interference, as much as
similar noises from q single circuit tuner
II not why2-A w. W.
Answer do not know of any such
legislation as you mention having been
enacted. 1t may be that something of
the sort has been proposed or is under
consideration, but | am sure that if it
/ had been enacted / would have been ad-
vised of the fact. The reason that a
double circuit set does not give the
same trouble from radiation as the
single circuit is because of the fact
that it is very rare that the secondary
circuit is exactly tuned to the natural
period of the aerial circuit. 1t is this
very reason that makes the double cir
cult receiver better for the purposes
of eliminating interference when re-
ceiving. The howls and squeaks that
are heard in the double circuit regen-
erative set are caused by the set itself
when it is not properly adjusted. 1t
can be caused by heterodyning or by a
number Of minor ills. The reason the
single circuit receiver radiates so we'll
is because the vacumm tube elements
cult, which will vibrate at it's own
natural period on the least provocation,
and that is the reason that the single
circuit makes the best form of trane-
mitter.
Question: have constructed three
tube super -regeneratiye receiver according
July 8, 1892, and after several weeks Of
effort have not received anything except
spark signals. Ny vario-couper Is made ,e,.te Of
for primary, with tap at TOP or beginning
of primary then tap every turn for six
more turns then tap every ten turns
turn or bottom end Of coil. Secondary is a
n Inch bail with 120 turns of No. "a sec
wire.
turns of No is sec wire In fiat plane.
wires spaced s. inch, Ends of loop run
to binding posts on panel. then to center
AIMS also from binding posts to
beginning and ending Of primary Of vario-
coupler Is this correct? 1 used wv 201
for first and second tubes and Nv 2o2 for
third tube. Have an S-volt battery and
use volts on first two tubes, with a sepa-
rate wire running from fourth cell of
battery to rheostat of third tube. Coils
and resistances are as shown in your dia-
gram.-W. " P.
Answer take it for granted that
the connections in your set are perfect
ly 0. K. The fact that you have Joined
the two ends of your primary vario-
coupler winding to the two switches is
perfectly all right, as that connection
acts as dead-end switch arrangement.
do not know just exactly how the
rotor Of your vario-coupler is ar
ranged; by that / mean whether it
turns completely around in a full cir
Gle or whether it only has 1870 degree
movement. If it works COMPLETELY
around ! would advise you to turne it
around very slowly and carefully while
listening in on the telephones. The
position of this rotor is very important
as the second tube will only oscillate
wnen the rotor is in certain pos .tion.
AS soon as you hear the shrill whistle
that sounds something like that of a
peanut sand furtaer adjustment of
the rotor or adjustment by means Of
the condenser C-1 will give you a Sc
ries OF peculiar whssline noise in