Radio Broadcast - 1925, February - 113 Pages ... - VacuumTubeEra

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A Word from an Enemy
of the Single Circuit
IT IS growing more and more plain that the
enemies of the single-circuit receiver are
legion and are increasing in numbers and in
intensity of their opposition. As has often
been remarked about the unfortunate widespread
use of the single circuit set, abolishing it
is so largely a matter of militant public opinion
that results come a bit slowly. RADIO BROAD-
CAST has in the last two years, lost some
"friends" by its constant advocacy of the abolishing
of the radiating receiver, chiefly among
advertisers, be it said. It is interesting to note
that now, very very few single-circuit receivers
are marketed by manufacturers who make
even faint claims to be reputable.
Editor, RADIO BROADCAST
Doubleday, Page & Company,
Garden City, L. I.
DEAR SIR.
I wish to compliment Mr. Willis K. Wing on his
excellent summing up of "The Case Against the
Radiating Receiver," but if it is in order, I would
suggest a final point with which he might have
rounded out his remarks on the single-circuit receiver.
Even if it were not for its severe radiation, the
single-circuit set is not even selective enough
to merit its consideration as a broadcast receiver.
The recent Department of Commerce ruling calling
for a compulsory quiet hour from 7 to 10.30 p. M.
on the part of amateur stations was necessitated by
the fact that at that time the single-circuit was the
commonest type of receiver in use. This was not on
account of the fact that amateur continuous wave
stations actually created interference themselves,
but simply because the single-circuit users were not
able to tune the near-by stations out, which is, in a
sense, unfair to the amateur.
This affliction of broad tuning which also gives
the same trouble when the receiver is in a few miles
of a broadcasting station, is caused by the fact that
when resistance is included in an oscillatory (tuning)
circuit, the tuning of that circuit is made broad. In
the single-circuit tuner, the coil, condenser, and
antenna are all connected together as to form one
circuit, hence the name. Unfortunately, however,
antennas have resistance, and most of those built
for broadcast reception have comparatively high
resistance, so that the antenna being included in the
circuit through which the signals enter the detector
causes the tuning to become broad. When the
tuner is set for a broadcasting station, any other
transmitter being operated in the neighborhood on
almost any other wavelength will be heard, probably
all over the dial.
The remedy for this is to "loose couple" the set;
in other words, to bring the antenna and ground
leads to a separate coil to be coupled to the grid
tuning coil. The honeycomb coil tuner is the outstanding
representative of this method of construction,
and the so-called three-circuit regenerator
as well.
H. S. G., Kitchener, Ontario.
A Radio Samaritan
TT IS most interesting to notice how the
1
gospel is reaching all through the country
and how the feeling against the squealing or
radiating receiver has taken practical form.
People, wherever possible, are getting to do
something about this unfortunate situation
rather than merely holding forth at great
wordy length.
Editor, RADIO BROADCAST
Doubleday, Page & Company,
Garden City, L. I.
DEAR SIR.
Since reading your article "The Case Against the
Radiating Receiver" in the October RADIO BROAD-
CAST, I came across this notice in our local paper.
B. N., Gloucester, Massachusetts.
RADIO CONDITIONS IN G1OUCESTEB LAST NIGHT
Conditions were good last night. Most stations came through
strong. There was very little fading and static. R. P. M.
WARNING
If the person in the vicinity of Center Street who tunes in
morning, noon and night and never gets the station clear'without
squealing, will please call at my shop, 101 Main St., with his or
her radio set. I will make the necessary adjustments and
changes in the set free of charge, so that above party will enjoy
his radio more, and others in this neighborhood may enjoy theirs
also.
R. P. MERCHANT.