ULTRA-SIIOKT-WAVE TRANSMISSION PHENOMENA 



375 



The 1.58 meter observations at 2500 feet fall off with distance in 

 fair agreement with theory (Fig. 7). The " out " curve is rough at 

 the shorter distances, as explained above. 



Observations at an altitude of 1000 feet occupied most of our 

 flying time. This was the lowest altitude which we cared to try, since 

 the plane had to remain within gliding distance of the shore. The 



H 30 



10 20 30 40 50 60 70 80 90 100 110 120 130 



MILES FROM TRANSMITTER 



Fig. 5 — Flight from transmitter. Wave-length — 4.6 meters; Altitude — 2500 feet; 

 October 11, 1933; 10:35 a.m. to 11:30 a.m. 



grazing distance for this altitude is 56 miles and, as the Montauk end 

 of Long Island is a little over 120 miles out, a considerable distance 

 where the transmission is below the earth's horizon was available. 

 At 1000 feet, at Montauk, the plane was 5000 feet, or 0.71 degree, 

 below the ocean grazing line from the transmitter. 



At 4.6 meters the first run (the flight of September 27), Fig. 8, 

 carried all the way out to Montauk. Subsequent runs (as Fig. 9) 

 carried barely half way, before the plane noise drowned out the signal. 



