SELECTIVE FADING OF MICUO WAVES 71 



Hero a roflectinjj; layer is situated l)et\veen the heif^-hts of the li-aiisnii(1(M- 

 and r(>('(M\-er. The signal then sul't'ers attenuation due to i'e(l(>cti()n of 

 |)art of tlu^ energy from th(> diicct path. Widely separated fi'e(|nencies 

 aie affected in like fashion and the outputs of anteinias sjjaced for 

 dix'ersity I'eception tend to be in agreement although th(> fine structure 

 fachng is usually different. 



On neither of the experimental transmission paths is there a I'geular 

 ground-i-eflected component of any conseciuence. Due to the roughness 

 of the giound and the presence of vegetation, the effective reflection coef- 

 ficient is of the order of 0.2 for eithei- path. (Ji'ound reflections thus play 



Fig. 3 — Possible ray paths involved in severe failing, (a) Multiple path trans- 

 mission, (b) Attenuation by reflection from an elevated layer, (c) Abnormal 

 water reflection on the Murray Hill-Crawford Ilill j^ath. (d) Substandard con- 

 ditions on the Southard Hill-Crawford Hill path. 



