I'm enquiring about frequencies used by airport ground vehicles, fuel bowsers in particular. Vehicles requesting clearance to enter an active runway do not seem to use the Tower frequencies, so assuming they're using a UHF frequency. I have tried for some length of time hunting it down without success. Does anyone have an up to date frequency that's in use?
I've noted a couple of frequencies in publications but these don't appear to be active. Any help would be very much appreciated. Best regards.