To get more gain than my current Picket -potter horn offers, i have build a system with a 45cm dish which i previusly used for 24GHz. the Dish has 45cm diameter and the dept is 6.5cm so the focal lenght can be calculated to 19.5cm , F/d=0,43. The Gain is 53,6dB and the 3dB beamwith is 0,37 deg. For the feed i use a length of 4mm OD /3mm ID cobbertube which is bend such that the open end is in the focal point. On the tranceiver side i use the W2IMU feed which has an output WG where the 4mm cobber tube fits inside:

Lab test over short distances indicate more than 35dB gain. The test setup is not very accurate , just indicating that gain is positive. Next step will be some field trials. It will also be interesting to see if its possible to use a dish with such small beamwith.