Abstract: A pneumatic tire monitoring system for monitoring pneumatic tire conditions for one or more tire/wheel assemblies mounted on a vehicle, preferably in combination with a tire pressurizing and regulating apparatus, comprises a transponder with a transmitting antenna mounted on the wheel for transmitting a signal indicating tire condition, one or more receivers with receiving antennas fixedly mounted on the vehicle, and circuitry for processing the received signals; the system characterized in that: circuitry for each transponder is on a printed circuit board within a protective housing coaxial to the hub of the wheel or wheel carrier; and each transmitting antenna is selected from the group comprising a partial loop antenna, a helical antenna, a circular dipole antenna, and a small coupling coil adjacent to an endless hoop antenna.