Daily Kennebec journal. [microfilm reel] (Augusta, Me.) 1870-1975, 1926-04-02

BY DIR. Alfred N. Goldsmith, Chief
Broadcast Engineer. Radio Corpora
ton Of America.
Let us assume that the transmit
ting stations from which the more
fortunate listeners receive their pro-
grams are really aecoustically syn
chronized so That they give a high
quality musical output and do SO re-
liably. Unless this is the case, the
listener is helpless because he can
hardly Systematically improve the
poor output of low grade stations.
All that the listener can do is sens
IDLY to choose the stations to which
he viii listen on the basis of the
quality of musical reproduction
which he can secure from hem.
When we come to the home of the
listener, however, we find that we
have reached a point where the
listener can and should take control
of the quality of the musical and
speech reproduction which he
secures by judicious choice and
proper manipulation of his receiving
set. 1t cannot be stated too emphati-
cally that by far the greater portion
of reception troubles result either
from poor receiving set or careless
manipulation of the receiver. In
this article only the receiving set will
be critically discussed, but in later
articles the, characteristics and i'm
portance of vacuum tubes and loud
speakers will also be presented in de-
tail.
A perfectly proper question on the
part of. the broadcast listener is:
How can a receiver in itself pro-
I,
causes the receiver to produce such
deficient resuhs?" The ideal receiy er
has a Stew simple and important
characteristics. 1t should permit
waves of all frequencies within a
band 90 kilocycles 10000 cycle
wide) TO pass through it with an
equality of admission of these fire.
quencies over the entire band. I'm
der such conditions. the quality of
the music would be practically in
dependent of tuning adjustments.
Unfortunately it has been neces-
sary to space broadcasting stations
in the United States 10 kilocycles
apart in order to take care of the
great number of determined pros
pective 4broadcasters. AS result,
practical American receiving sets
should admit frequency band not
much over 10 kiiocycles wide. al
though this begins to impose a
limitation on the quality of the re-
ceived music or speech and also nee
essarily causes the tuning adjust
ment to have some influence on the
tone quality which is produced.
Another characteristic of an ideal
receiver is that its final output is the
same for all audible frequencies from
the lowest tone of the organ to the
highest overtone of the violin or
piccolo. II the receiver does not
respond proportionately to all aud
ible frequencies, acoustic synchroniZ-
ing Is lost and the sounds in the
studio and the corresponding re-
production of the sound in the home
are no longer accurately alike.
There are number of places in a
broadcast receiver where trouble
may arise which detracts from the
quality of reproduction. In every case
there is necessarily supplied tun-
ing handle or handles, generally
known as the radio frequency tun-
ing adjustments. If the tuning of the
receiving set is too sharp (that is,
il there are too many sharply tuned
radio frequency stages in the receiv-
ing set and they are all accurately
tuned to the<same frequency, it Will
be found that there is a loss i'll tone
quality and that either low fire.
quency notes or high frequency
notes will be sighted depending up
on the setting of the tuning dials.
A good way of finding out whether
this fault exists to AN appreciate
extent in a receiver is to tune 1t. on
quiet" night when there is little
static, to fairly distant station and
to bring the signals up to the maxi
mum intensity by sharp tuning, and
the manipulation of any additional
controls (for example, the "tickler''
handle) which brings the signal to
its strongest value. If, after this has
been done, slight shifts of the tun-