Sinclair Q2220-E VHF Duplexer 138-174 MHz 350W 70dB Isolation

The Sinclair Q2220-E is a VHF Band Pass/Band Reject duplexer engineered for demanding shared-antenna installations across the 138–174 MHz band. Built around a quarter-wave bandpass filter topology with four 4-inch cavities, it delivers a minimum of 70 dB isolation at a channel separation as tight as 0.5 MHz, making it well suited for co-located transmit and receive systems operating in congested RF environments. Copper and silver inner conductors, silver-plated throughout, provide long-term corrosion resistance and consistent electrical performance over the unit's operational life. With a 350 W maximum power rating and a worst-case insertion loss of only 1.5 dB, the Q2220-E supports high-power base station deployments where protecting receiver sensitivity and suppressing spurious emissions are critical requirements. It is the appropriate choice for sites subject to elevated levels of interference, intermodulation, and desensitization.

Key features & benefits

• Quarter-Wave Bandpass Filter Design — The four-cavity bandpass/band-reject topology provides a minimum of 70 dB isolation between transmit and receive paths at separations as close as 0.5 MHz, effectively protecting receiver front ends from transmitter overload.
• High Power Handling — Rated to 350 W maximum, the Q2220-E accommodates high-power VHF base station transmitters without derating across the full 138–174 MHz operating band.
• Low Insertion Loss — A maximum insertion loss of 1.5 dB preserves transmit power and receiver sensitivity, minimizing the impact of the duplexer on overall link budget.
• Silver-Plated Copper Inner Conductors — Copper and silver inner conductors finished with a silver plating resist corrosion and maintain low contact resistance, contributing to stable long-term RF performance.
• Interference and Spurious Suppression — The band pass/band reject architecture actively reduces intermodulation products and desensitization while eliminating spurious radiation from the antenna port, making it especially effective in high-interference environments.
• Standard N Female Connectivity — All ports terminate in N female connectors, ensuring compatibility with the industry-standard coaxial interfaces common to VHF base station and repeater infrastructure.
• Wide Operating Temperature Range — Specified from -40 °F to 140 °F (-40 °C to 60 °C), the Q2220-E is suitable for both indoor equipment rooms and outdoor or semi-exposed enclosures subject to temperature extremes.