OK, I see. Perhaps multifeed system like this could work for your antenna. It is possible to have C-band LNB in the middle and Ku-band one in multifeed, but also can be opposite. If dish is motorized than multifeeded LNB should be placed very carefully and precisely to catch signals from more...
Why to the dish arm and not to the C-band LNB? Perhaps it is even better to install Ku-band LNB in antenna's focus and C-band LNB in multifeed. How many feedarms your antenna has? Is it motorized? Couple of pictures would be nice to see.
In my opinion you have at least 3 options. I will list them in my preference sequence.
1- make ne holder and install LNBF like Inverto Black Ultra (IBU);
2- adjust IBU to original Prodelin feedhorn;
3- mess around flange LNB connected to original Prodelin feedhorn, polarizer and other expensive...
I was playing around some metal parts another day and came to solution like this You maybe do not need C-band LNB to be mounted but only Ku-band. This would allow precise adjusting of the LNB in all possible directions.
Folks! I hav ejust got another "toy" to my yard. Seems that it is made in USA. Looking for more info , like name, brand, characteristics, reception feedback, etc. It is made of thin glass (less than 4mm) and weights almost 16 kg. Yes, need info :)
I was trying to make something universal and durable another day. Came up with such a construction. All INOX made and can be installed on any offset antenna (round or square feedarm). However, I do not like multifeeds, they steal signal.... unless they are installed on multi-focus antenna.
Reception-wise GSP and CM are more or less the same (as their reflecting surfaces are same). But CM is very durable antenna and will never change it's shape, so I would choose it. But do not buy new, take from second-hand market.