RECEIVING SIGNALS FROM OVERSEAS
Intensities of broadcasts picked up from ten test stations in such distant places as England, Honolulu, Africa and Chile are continually recorded (picture) at the Sterling, Va., Radio Receiving Station of the National Bureau of Standards.
These records are used to study the amount radio waves are absorbed by the ionosphere.
Tubes used in sending radio impulses into the ionosphere to determine the height of the layer from which the waves will bounce back to earth [were shown in the SNL article].
Sunspots can be expected to cause a blackout of shortwave radio broadcasts.
The largest sunspot observed by the U. S. Naval Observatory is about fifteen times as large as the earth.
Original Caption by Science Service