Evening star. [volume] (Washington, D.C.) 1854-1972, 1923-05-20

! that the geological theory seems TO
bear more directly on the Washing
ton Baltimore problem than others
which have been advanced.
In support of the geological theory.
. il Is said that there are fairly album
dant deposits of rock formation
known as "gabbro" in and around
Baltimore. "Gabbro." according to DR..
of Maryland. contains a certain
amount of iron, which may have some
pflect on magnetism.
Scientists at the bureau of stand
ards as well as DR. kounwennoven.
lem does not lie in topographic con-
ditions for the reason that no similar
ity has been found to exist between
the topography of the different dead
spots" Other such spots exist be-
sides Washington and baltimore
Cleveland, for instance, is not on radio
speaking terms with Pittsburgh. At
-lanta and Chattanooga, likewise, de-
He.:to listen to each others radio
voice, and the same is tru eof Spring
field and Boston. Los Angeles is
virtually deaf SO far as radio mes
sages from its neighbor. San Fran
-ciScoY-~and yet il receives distinctly
similar communications from Port
land Ore. which. pass directly over
San Francisco.
:.
Some deep-rooted beliefs as to the
causes of Interference with broad
cast reception are set at nauRht by an
investigat ton. of this subject now be-
ring made under the direction Of Prof.
9: NJ. Jansky jr. of the University of
Minnesota, in conjunction with the
bureau of standards radio laboratory
| ceived by the American Radio Relay
| League which Is cooperating with
the bureaus staff.
Every owner of a receiving set has
experienced some form of interference
with reception of broadcast programs
and frequently his ideas as to the
actual reasons for such Interruptions
nave been erroneous. Obstacles to
| receiving, the report states. may be
divided into two general groups,
! and from human agencies.
| The results are based on observa.
tons of reception from KDKA at East
Pittsburgh, Pa, and WLB at Mime
/ apolis, Mimi, between August. 1922,
I and February, 1928. During the ini-
tial observations until September Is,
interference from amateur telegraph
| stations amounted to less than per
cent, and throughout the entire period
the average interference from anna
| per cent and from amateur continu-
! Gus wave stations only 2.3 per cent of
the. total interference observed,
! BY far the greatest amount Of in
| reference was caused by natural
sources such as fading and static, and
from broadcast sending and receiving
stations themselves; this In ali
amounting to BIS per cent. This
has been classified. specifically; inter-
| ference from other broadcast stations,
! 800 per cent; atmospherics, 1871; fad
ing, 1876; commercial stations, 81;
| other: receiving sets. SO. and power
| lines, IL per cent. Reception of
broadcasts without any interference
! whatever was experienced during
only 23.3 per cent of the total observ.
| atoms.
! Demand s'WirelesS Freedom.
Americas radio problems are looms
/ ing larger and leaders In the industry
FIN this country are studying the SIT
uation in England, where. demand
for; wireless freedom" and relief from,
| the boredom of the iusterless pros
] grams" has gone up.
! Conditions on this side Of the At.
| lantic, 1t is pointed out, cannot be
finally resolved without close consid-
! GRAFTON of the point of view of the in
n sx-f A iafn lot,