The PPS-100 Pre/Postselector permits operation of co-located receivers and transmitters on frequencies separated by as little as 10%.

When used with receivers, the unit functions as a preselector, providing an additional front end selectivity stage. This reduces the receiver desensitization and overload that would normally occur in the presence of strong adjacent RF transmissions.

The unit is used as a postselector with transmitters. It rejects spurious outputs and broadband noise in the transmit signal before it reaches the power amplifier, thereby limiting interference to neighboring receivers.

The PPS-100 performs both functions with a transceiver; it follows the radio’s key line and switches between the preselector and postselector modes.