Just wanted to share and discuss with you my idea of how to decrease RF interference from wifi and similar devices when flying using 2.4 ghz for video.
In general, most of us good FPV guys put a circular polarized antenna on a quad and use a high-gain linear polarized antenna at the receiving end, thus having a 3 db loss from cross-polarization. On the RX end in most cases without thinking on it twice we put our patches or yagis so that they actually work in vertical polarization...
The idea is to use horizontal polarization on the receiving end in order to significantly decrease the interference, especially when flying in urban areas.
As far as I know most part of the devices that could generate interference on 2.4 ghz band transmit in vertical polarization. Just take a look at your router! So when you try to receive a vertically polarized signal with a horizontally polarized antenna, cross polarization losses theoretically can be infinite, but in practice can easily reach 10-20 db. It's a pure gain in signal to noise ratio