The Telewave model TPRD-4554 duplexer allows simultaneous operation of a transmitter and receiver into a common antenna. These pass-reject duplexers are ideal for systems with very close frequency spacing of 1 MHz or more. The Telewave TPRD-4554 has two-wave pass-reject cavities in the transmitter and receiver sections. Because of their superior construction, these Telewave 5 in cavity duplexers achieve greater rejection of transmitter spurious and noise radiation, providing excellent receiver protection. All duplexers are tuned and tested with customer-specified frequencies prior to shipping. If frequency changes are required, the positive locking mechanism allows for easy field tuning by rotating the threaded Invar rod.