I have tried to improve my uplink with a 120cm dish. This is an old commercial dish with a low f/D 0.25.
Now I am using linear polarised WiFi grid antenna PW 24 dBi,
Due the low f/D I have choose K3TZ patch feed. I was calculating with a gain of 3dB for circular polarisation and 6dB for mechanical dimensions.
Test shows only +3dB.
I can confirm that th feed was placed correctly in focal point and SWR was not bad (indication on LZ5HP's XVRT), The reason why I did not reach the estimated gain is probably that the feed has not so wide radiation angle as I need for f/D 0.25.
To imagine that 120cm dish has 30.8cm depth and focal point is 29.2cm from it depth.
Has anybody an idea for circular feed for this parabolic dish, please let me know.