60 



TRANSMISSION EXPERIMENTS IN ENGLAND 



system may be suitable for ai^plication under opera- 

 tional conditions.^ 



''It has appeared since the November 1944 Propagation 

 Conference that the Propagation Group at San Diego has 

 found a good correlation between the radio data and a simple 

 meteorological parameter based on temperature excess. In the 

 British Isles the temperature excess has to be taken between 



a height of about 200 ft and sea level, whereas at San Diego 

 the temperature excess has to be taken between a height of 

 about 5,000 ft and sea level. It has also been reported that in 

 the Pacific Area temperature excess is by far the best index 

 for predicting radio propagation conditions. There is some 

 hope, therefore, that it may be possible to work out a method 

 of fairly universal application on the basis of temperature 

 excess. 



