Evening star. [volume] (Washington, D.C.) 1854-1972, 1929-05-05
INDOOR AERIAL AIDS
APARTMENT FANS
Sensitive Receiver NeCeS-
sary, However, in Order to
Obtain Loud Signals.
BY JOHN F. RIDER.

! Special Dispatch to The Star.
! NEW YORK, May 4-Dwellers in
the larger and newer types of modern
| apartment buildings are usually at
disadvantage for home radio reception,
particularly those living on the lower
floors. 1t is quite difficult job to erect
an outdoor antenna of the right char
actertistics from the third or fourth
! floors of a History steel building. Most
: of the antenna would be lead-in. The
novice would be justly puzzled to deter
mine where the antenna left of and
/ the lead-in began. And when the job
is completed it does not always work
! so we'll. What, then, is the solution?
/ What If the owners of the building do
/ not allow the erection of outdoor an
| tennas at all?
Some interesting observations with
receivers so situated were made during
| the course of experimental work carried
cut in several large apartment build
| ings. The subject of the experiment
was the determination of radio receiver
response with indoor antenna, dispens-
ing completely with outdoor aerials.
Several Types Tried.
Several different indoor aerials of
| other than the loop type were first
/ placed into position. These varied in
length from Is to 40 feet, and in physi-
cal location from the molding near the
| room ceiling to the base of the wall and
beneath the rug.
| 1t was found that the main concern
regarding the type of receiver to be
| used for this purpose was that it should
be of extreme SenSitivity. It had to
have large amount of radio frequency
amplification, plenty Of gain, and
number of stages.
With an indoor antenna in a steel
building and receiver with four stages
of radio frequency application, of
which three stages were tuned, de-
tector and three stages of audio fire.
quency amplification, local reception was
satisfactory at all times, with very
little dtrectional characteristics. AS to
senSitivity, a sufficient number of dis
tant stations were received to justify
the use of the indoor aerials. The di-
regional qualities of the indoor an
tennaS were more prominent when re-
ceiving distant stations than when the
locals were coming through. This char
acteriStic, however, is also noted with
many outdoor aerials.
Steel Shell Is Pierced.
One is very likely to imagine that an
indoor antenna will be ineffective in a
large steel building, inasmuch as a
steel building is usually considered as a
oAASAOON DbA uSIuAC JAldI IdUlO waves Will
not penetrate. The experiments in q
number of large steel buildings dis
proved this idea. but it must be ad-
mitted that a sensitive receiver must be
used If the indoor aerial is to be eff
fective. This fact was conclusively
demonstrated during the test when the
eight-tube receiver was replaced by a
five-valve receiver with two stages of
radio frequency application. The re-
ce1ver signal response was very unsat-
isfactory.
Considering the conditions existing
in such houses, reception with an in
door antenna is practical. It is posi-
BILE when necessary to satisfactorily dis
pense with the outdoor aerial. One
need not imagine when he moves into
a large apartment structure, where out
side aerials are impossible, that salts
factory radio reception, too, is banned.
The important thing to remember in
the case Of radio reception in large
steel apartment houses or in a hotel,
with the indoor antenna the only
means of pickup available, is that the
receiver must have plenty of radio fire.
quency application, which means that
1t will have enough gain to strengthen
the radio currents that are induced in
such small antenna, so that the cur
rents will be strong enough to make a
good, healthy response in the signals
that issue from the loud speaker.