Evening star., 1928-10-31
GRANITE BLAMED
FOR RADIO BLANKS
Areas of Poor Reception Are
Being Investigated to
Find Cause.

Fading dead spots" in the ether and
other conditions that make radio re-
ception abominable in vast areas of the
country-the latest phenomena to be
recognized by radio day-may actually
be "as old as the hills"
A brand-new clue as to the causes of
these freakish impediments to reception
give rise to the theory that they are not
in the air at all, but within the earth's
crust. Granite beds and other igneous
rocks, which were formed by the actions
of heat perhaps hundreds of millions
of years back, are held to be response
BILE for the poor transmission of radio
waves, and because substantial pro-
portion of the country is underlain with
this substance, great importance at
taches to the theory.
Radio engineers lately have been i'm
pressed with the fact that the granite
areas are the chief complainants of
fading and dead spots" and now are
looking forward to the findings Of geol-
ogists on this theory. That geology
is a factor in radio transmission is
new thought, and the plan is to CO.
ordinate the idiosyncraSies of radio
transmission with those OF geology, and
perhaps arrive at means OF solving
this vexatious problem.
Investigation Urged.
DR.. George Otis Smith, director Of
the United States Geological Survey,
declares this is one of the many things
that must be investigated. and that
the problem will be attacked as soon as
ways and means are found. The Naval
Research Laboratory, Bellevue, .. c.,
also is considering an investigation. Ra-
dio Commissioner Caldwell, himself an
amateur geologiSt, Is urging such tnves-
legations DR.. j. H. Dellinger, chief
engineer of the Radio Commission and
one of the foremost radio authorities
of the Nation, believes that findings
of such surveys should be collated
with existing knowledge of the vaga-
ries of radio waves in the interest of
working out the maze of scientific prob
lens that confront radio,
The scant knowledge OF the relation
ship of geology to radio transmission
shows that reception is best over lime
stone and sandstone surfaces. Radio
waves are known to travel best over
sheets of water and level surfaces,
whereas the granite country usually Is
hilly.
The present general belief is that
| peculiar regional atmospheric condi-
tions, geographical contour OF sections
of the country, and the magnetism of
metal deposits, steel construction and
| the like prevent the entry of the waves
in the poor radio areas. But from the
circumstantial evidence there seems to
| be sound basis for the theory OF
granite interference.
Areas for Poor Reception.
Almost all of New England IS granite
country and the Rockies are largely OF
| granite, as are the Sierra NevadaS
| along the Pacific Along the Southern
seaboard in the Appalachians there is
considerable of the substance, and in
all these areas distance reception is
anything but good On the other hand
reception in the Western plains regions
is excellent both day and night, and
in that territory there is little or no
granite.
Commissioner Caldwell points out
that station WBZ, Springfield, Mass
cannot be heard effectively in Boston
60 miles distant, and for. that reason
station WBZA was established in Bos-
ton to broadcast the former stations
programs on wired synchronization
basis. There is a spot in Springfield
within sight of WBZ's towers that can
not receive the station well, most like
ly because of the granite areas.
at his home in Greenwich. Conn.
inst 100 miles. away from WBZ. Mr.
Caldwell says Ae cannot get the sta