Duplexer VHF 144-175 MHz

A duplexer lets one antenna carry both the transmitter and the receiver at once. Without it, a repeater needs two antennas far enough apart that the transmitter does not deafen its own receiver, which on most sites means a second mast position that is not available.

The filter is tuned before it ships, and how it is tuned decides what it delivers. Tuned to a single pair of frequencies it suppresses more than 80 dB, both of transmitter noise on the receive frequency and of the transmit signal reaching the receiver, at an insertion loss of 1.2 dB. Tuned across a band for multi-channel use it holds more than 40 dB at 1.4 dB. On this band the difference between the two is large, which is why the frequencies are asked for at the time of order.

Six cavities sit in an extruded aluminium housing on a passivated steel chassis, with PTFE insulation in the rigid coaxial cables and the connectors. The outside is vinyl-coated against corrosion. Frequency stability is around 5 ppm per degree, and the filter is rated from −30 °C to +60 °C.

Also available for other bands: UHF 400-470 MHz, VHF 68-88 MHz and Marine VHF. Mounting plate MP002 is ordered separately. Contact sales for special solutions.