Coaxial RF Cable length issue

3 days ago i received my free FlightFeeder from FlightAware i installed my Antenna everything works as expected my problem is the Coaxial Cable is too short from where i want to put the FlightFeeder computer, is it ok to modify the Coaxial Cable to gain more length? will the modification affect the signal strength?

thank you

What sort of modifications are you looking to do? My assumption would be that it would have some effect, but I will let someone with more knowledge answer in more detail.