## Historical and technical survey |

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Page 121

Near the antenna the wavef ront (the locus of points of constant transit time) is

spherical, but at great distances it is practically

principle each point of a wavefront may be considered as a source emitting

wavelets ...

Near the antenna the wavef ront (the locus of points of constant transit time) is

spherical, but at great distances it is practically

**plane**. According to Huyghens'principle each point of a wavefront may be considered as a source emitting

wavelets ...

Page 149

In Figure 49 is shown a transmitter of height hi above the horizontal

The radius of the standard earth is ka. At D, the center of the reflection area for

the lobe considered, is drawn a tangent

distance ...

In Figure 49 is shown a transmitter of height hi above the horizontal

**plane**GH.The radius of the standard earth is ka. At D, the center of the reflection area for

the lobe considered, is drawn a tangent

**plane**CDE, which intersects hi at adistance ...

Page 193

The coverage diagram drawn for propagation over a perfectly conducting

on horizontal polarization is illustrated in Figure 5. As an example, consider FLAT

EARTH Figure 5. Simplified coverage diagram. /=200 mc, X = 1.5 m, A,=30.5 m.

The coverage diagram drawn for propagation over a perfectly conducting

**plane**on horizontal polarization is illustrated in Figure 5. As an example, consider FLAT

EARTH Figure 5. Simplified coverage diagram. /=200 mc, X = 1.5 m, A,=30.5 m.

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altitude Anomalous Propagation antenna attenuation azimuth band characteristic values Committee on Propagation computed constant coverage diagram CUDWR curvature curve decibels decrease determine diffraction diffraction region direct distance Division 14 Report duct earth effect elevation equation equipment experiments factor field intensity field strength free space frequency Fresnel zones functions gradient ground height horizontal humidity index of refraction JEIA land layer lobe angles maximum measurements meter method microwave miles mode moisture NDRC nonstandard propagation NRSL obtained operational optical OSRD path difference pattern permanent echoes phase plane plotted polarization problem radar radar cross section Radio Propagation Radio Waves radius range receiver reflection coefficient refractive index region Research signal strength Snell's law standard atmosphere superrefraction target temperature inversion theory tion transmission transmitter trapping Tropospheric variation vertical Wave Propagation Wave Propagation Group wavelength weather X band zone