problems with f-connector

hi, folks
I have hit a F-connector problem. I need a F-Connector with a frequency rang from 0---2.5GHz as my tuner input interface, the problem is the availabe connectors are far away to the frequency rang requirement, only have a range of 0---1.5GHz, anyone has any idea on how can I compensate the singal due to frequency mismatch?
many thanks..