4:1 coax cable balun

[guanxiaolong]

Hi,everyone,In this picture,we can see the PA circuit board.The input port has a balun with transformer (4:1) using a ferrite,and the output has the 4:1 coax cable transformer and the coax cable balun. The frequency is 50MHz to 75MHz. I have two question for your help, thank you very much.
The first question is about the balun with transformer (4:1) using a ferrite in the input port. How to make it in particular requirement, for example,how to choose the ferrite, how to match the tansistor input impedance,50/4=12.4 is rigth for the transistor(FREESCALE MRFE6VP61K25H).
The second question is about the 4:1 coax cable transformer and the coax cable balun in the output port. How to calculate the length and the impedance of the coax cable.
Thanks,wish you good luck.

 

[kspalla]

here is link for ferrite
**broken link removed**