The link below leads to two graphics showing the __accurately measured__ fields using various numbers of buried radials of 0.274 and 0.412 wavelengths (radial lengths as measured in free space). These graphics show the groundwave fields for linear, unloaded monopoles up to about 95 degrees in electrical height. Earth conductivity at that test site in New Jersey was not higher than 4 mS/m.
The elevation fields of these monopoles varies approximately as the cosine of the elevation angle. Maximum radiated field always occurs in the horizontal plane for these electrical heights -- so the greater that field in the horizontal plane, the greater the field at angles above the horizontal plane. Pattern shapes for monopoles of these electrical heights are independent of the operating frequency. The data show that the system using 113 x 0.412-wave buried radials produces the highest field, particularly for shorter monopole heights. It is a judgment call as to what set of buried radials is needed by the user. AM broadcast stations typically use 120 x 1/4-wave (or longer) buried radials, but amateur stations may not be able to justify this. http://i62.photobucket.com/albums/h85/rfry-100/BLandERadials.gif _______________________________________________ UR RST IS ... ... ..9 QSB QSB - hw? BK
