Today i tested those sweet 5.8GHz circular polarized antennas (in fact i am using the helical for a while and wanted to give the patch antenna a try).
With a Foxtech 400mW Tx on the plane and two RC305 receivers on the groundstation, i flew 5km away and compared the picture quality.
Of course i was expecting, that the patch outperforms the helical, due to it’s higher dbi rating (13dbi vs. 12.5dbi) but in was the other way around.
The circular-wireless 7,5turn helical still beats the shit out that new cp patch antenna. Both signals were good (just some color noise in that distance), but there was a lot more color noise with the patch antenna.
On my way back i also switched between both antennas a few times and the helical always gave me the cleaner signal/picture.