Kenwood MA-4000

The Kenwood MA-4000 is a high-performance diplexer/duplexer engineered for amateur radio applications. It facilitates simultaneous operation on the 2-meter (144–148 MHz) and 70-centimeter (430–440 MHz) VHF/UHF frequency bands. This device enables a single dual-band transceiver to interface with separate VHF and UHF antennas or combines two coaxial feeds into a single dual-band antenna, optimizing system efficiency for both mobile and base station configurations.

Technical Specifications:

• Frequency Range:
  • VHF: 144–148 MHz
  • UHF: 430–440 MHz
• Power Handling: 50 W (maximum, continuous wave)
• Impedance: 50 ohms (nominal, input and output)
• Insertion Loss:
  • VHF: ≤ 0.2 dB
  • UHF: ≤ 0.3 dB
• Isolation:  ≥ 60 dB (between VHF and UHF ports)
• VSWR: ≤ 1.2:1 (typical, both bands)
• Connectors:
  • Common port: SO-239 (UHF female)
  • Band-specific ports: PL-259 (UHF male)
• Dimensions:  Compact design, approximately 90 mm (W) × 70 mm (D) × 30 mm (H)
• Weight: Approximately 300 g
• Construction: Durable aluminum housing with weather-resistant sealing

Operational Characteristics:
The MA-4000 employs high-Q bandpass and band-reject filtering to achieve exceptional signal isolation between the VHF and UHF bands, minimizing cross-band interference. Its low insertion loss ensures efficient power transfer, while the high isolation rating prevents signal leakage between ports. The device supports both transmit and receive functions, making it suitable for full-duplex or simplex operations.

Applications:
Designed for amateur radio operators, the MA-4000 is ideal for scenarios requiring dual-band functionality, such as satellite communication, repeater access, or mobile setups. Its robust construction ensures reliability in varied environmental conditions, and the compact form factor facilitates integration into space-constrained installations.