If the radiation at 3 degrees is -8.9 dB relative to the maximum amplitude we can still work DX.
Dave WX7G On May 8, 2012 9:18 AM, "Richard Fry" <r...@adams.net> wrote: > Dave WX7G wrote: > > >The program W6ELProp gives the take-off-angle needed for any path. Looking > >at 80 meter paths (it does 801-0 meters) the angles for DX paths are in > the > >range of 3-15 degrees. > > Assuming those angles are true for DX paths, note that if the NEC far-field > elevation pattern for a 1/4-wave monopole was the only radiation leaving > the > antenna, the field at 3 degrees elevation would be about 8.9 dB below the > field at the center of the so called take-off angle (see link below - note > Photobucket stripped the decimal from the 3.9MHz link). > > The surface wave really needs to be recognized in such evaluations. > > http://i62.photobucket.com/albums/h85/rfry-100/39MHz_Elepat_6_mS.jpg > > > > _______________________________________________ > UR RST IS ... ... ..9 QSB QSB - hw? BK > _______________________________________________ UR RST IS ... ... ..9 QSB QSB - hw? BK