A statiscal method to evaluate TX antenna performance using WSPR - more...

The following graphs are based on a significative number of spots and show, what can be expected from the method described in the previous post. All have been done on 30m, as for the moment it is the band where the WSPR activity is maximum. The above graph, shows all the spots (about 2500) collected from 23 april 10:00 to 25 april 5:00 for the 2 antennas under test (5/8 vertical and dipole at 10m). Such a graph may look useless but similar plotting may be of interest for contesters, who want to reach a maximum of stations in all directions at all distances in a limited period of time. The slight superiority of the vertical can be easily explained by the fact that it is omnidirectionnal, thus allows a stronger signal in all directions, even at short distances. This would look probably different on lower bands, where high angle signals are more dominant for non DX stations. It would also probably look different with a 1/2 wave vertical which has a sharper pattern in the vertical plane and unlike the 5/8 no secondary lobe at high angle (see the article describing my vertical ).
For the above graph, I only used the data from DX stations (>5000kms - about 650 spots). It should be noted that the orientation of the dipole (310/130) is near to optimum for a huge majority of the spotters. It just confirms antenna simulation and what all experienced DX'ers and contesters know: For DX, a well designed verticaly polarized antenna is better than a horizontaly polarized antenna, if below 0.5wl AGL.
By the way an interesting phenomena can be observed on day 2 between 14 and 20z, when the dipole seem to exhibit slightly better performance than the vertical. It could be explained, by some higher angle mode of propagation (ie E's+F) during this particular period of time... but of course this is just an hypothesis...