San Antonio light. [volume] (San Antonio, Tex.) 1911-1993, 1925-10-25
LIST 8 SOURCES
Of RECEPTION
TROUBLES
Tubes and "B" Batteries
Are Often Cause Of
Poor Performance.

Radio reception has not yet reached
that foOl-proof stage where it is only
necessary to turn a switch to secure
continuous satisfactory production.
How many times have you looked
forward to some broadcast program of
particular interest, only to be greeted
by flood of jumbled harshness belch-
ing from the horn of the loud speaker.
1t interferes with the program, it
CRATES upon the nerves Of the listener,
and tries the patience Of those people
who desire quality reception, unac-
companied by this Objectionable noise.
Let us consider the sources of these
noises.
First, we have the studio noises
which may be defined as those noises
which originate at the broadcasting
station. Noisy microphones cause a
steady hiss which often blurs the voice
OF the artist. Programs picked up
outside of the studio and carried over
land by wire for broadcasting are
usually excessively noisy by induction
from neighboring wires-a steady
rushing sound, especially noticeable
when the receiver is tuned to reson-
ance, is caused by the generator which
supplies the plate potential to the
transmitter tubes. This noise is more
or less pronounced on all stations and
continues until the broadcasting is
finished and the stations sign off the
air.
| Noise contributed by the other me-
dunn may be defined as those sounds
which are caused by electrical disturb
ances between the broadcasting sta
ton and the receiver itself. In this
group are found the disturbing influ.
ences of high tension power lines vio-
let and X-ray machines, leaky trans
formers, electrically operated eleya-
TORS, sparkling motors and generators,
trolley and elevated railway systems
and telephone and telegraph wires.
Electrical impulses from these unde-
slrable sources usually occur ut short
wave lengths and are picked up by
sensitive receivers. Static also comes
IN this class and is more or less prev
aient throughout the summer months.
Many satisfactory programs are sud-
denly broken up by a series of unfa-
mlliar clicks and in many cases arc
interrupted entirely for short periods.
THESE are caused by key clicks from
continuous wave transmitters and by
Improperly operated regeneratiye and
supcr-heterodyne receivers.
In the third class are the noises
which are caused by the receiver it,
self or by the equipment which is used
IN connection with the same. Dis.
charged "B" batteries become noisy
ana are usually the cause of high
pitched squeal when the receiver is
| operating on the second audio stage.
THESE batteries should be discarded
when their voltage drops below "a.
Storage "B' batteries often cause the
same trouble even when the voltmeter
reading is high. SqueaIs in this case
are caused by one or more dead cells
which are usually not detected unless
voltmeter reading is taken of each
individual cell.
Noises are sometimes caused by the
vacuum tubes themselves. While iden-
teal in appearance, it sometimes ham
pens that their internal elements arc
not rigidly supported, and any dis
turbancc in the vicinity of the re-
ceiver may cause these elements To
vibrate. This defect in construction
produces bell-like sound which may
build uD in volume and drown out the
program. This may be overcome BY
until satisfactory combination is
shifting the tubes about in the sockets
| found.