4:1 coax cable balun

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.

here is link for ferrite
http://www.2dipol.com/2013/08/aperio...te-baluns.html