Following this tutorial I built an SPW for my 5.8Ghz 200mW kit and today I've tested it on my FPV EasyStar.
I did 3 tests...but the results with SPW are not very cool:
1 - standard whip antenna on VTX and VRX
2 - SPW on VRX and whip on VTX
3 - SPW on VTX and whip on VRX
On flight 1, without SPW, I reached 1.000m with some grain after 600m and some disturbance around 900-1000m but the visual was good
On flight 2 I reached 500m with a good image, probably better than flight 1, but after 500m I got a lot of disturbance and around 800m I had to come back as there were a lot of grain and disturbance
On flight 3 I was not able to get 500m and I had to came back very soon.
I know that my SPW is probably not perfect as geometry ...but building these 5.8Ghz antennas it's not so easy.
Next days I'll try with a Cloverleaf or a Vee on VTX and the SPW on VRX and see if I can get better results.