Where can I buy a KU FEEDHORN with F/D ratio of 0.3

I purchased a 3.0M Prime Focus Prodelin antenna ( part number 1304) that has an F/D ratio of 0.3 it's a DEEP ANTENNA.

I need to use it to receive Astra and Hotbird (Europe) Ku Band transmission 10.75- 12.7 Ghz

I am unable to find a feed horn that uses C120 Connecting LNB that is in the range of F/D 0.3

Anyone knows where I can find this kind of Feed horn

The nearest I could find is From Global Invacom That is an adjustable feed with F/D 0.32 - 0.43

http://www.gionlineshop.co.uk/produc...ed%20Horn&sm=1

I am trying to receive a very very weak signal so any small increase in gain is a massive help.

Please help with any solution possible,
Thanks