Abstract: A method and apparatus for calculating the travel time of a vehicle as it transits through multiple locations. The method and apparatus includes a device for detecting a radio signal from a vehicle, attaching information to the radio signal, and transmitting a message packet with the signal and attached information to a central server. The central server stores the message packet. The central server compares the information in the message packet against other stored message packets received from multiple locations. When matching information is found, an algorithm is run to compute a vehicle travel time between two locations.

Abstract: A method and apparatus for calculating the travel time of a vehicle as it transits through multiple locations. The method and apparatus includes a device for detecting a radio signal from a vehicle, attaching information to the radio signal, and transmitting a message packet with the signal and attached information to a central server. The central server stores the message packet. The central server compares the information in the message packet against other stored message packets received from multiple locations. When matching information is found, an algorithm is run to compute a vehicle travel time between two locations.

Abstract: A tunable resonant cavity filter structure is disclosed which includes an enhanced ground return internal to the cavity which effectively eliminates generation of deterioration wide band noise and optimizes unloaded Q as well as rending resonant frequency stable with vibration. In its preferred form, the enhanced ground return is in the form of a ground return clip with reliant radial projections that mate with the threads of the threadable tuning element used to determine final operating frequency. The radial projections are deflected in cantilever fashion so as to generate sufficient pressure to break thru any oxides in the tuning element threads and ensure metal-to-metal contact.