phase differences with predicted diurnal variations are 

 shown in figures 5 to 9. A complete set of such curves has 

 been compiled as a supplement to this report.^ 



The computer predictions are no more accurate 

 than the basic prediction model employed and hence the limi- 

 tations previously discussed apply; the effects of the second 

 and higher propagation modes should be considered when 

 using a nearby transmitter. In practice, operation within 

 1000 n.mi. of a station was not advised although the correc- 

 tions provided were valid first-mode predictions to 840 n.mi. 



60 

 40 



!•• ••••••••• 



••....;::t;;;. 



60 

 40 

 20 



00 

 0000 



1200 1600 2000 2400 



TIME (GMT) 



Figure 5. Bathurst, Gambia: Forestporf -Summit, 10.2-kc/s Omega phase difference 

 (4 to 6 Dec 63). 



20 



