Image of 28-36-02A Duplexer


Image of D-Star Logo

D-Star Solutions 28-37-02A, 144-174 MHz, Duplexer

  • TX RX Systems offers a wide variety of Duplexer options to suit your application, including Vari-Notch®, Bandpass, and notch type circuits
  • Vari-Notch® design provides low loss and high isolation in a compact package
  • All high RF-current components silver-plated for highest performance
  • Various models to choose from to match your application.


Specifications for duplexers of unsymmetrical construction or response are listed as follows:

  • Isolation: Noise Suppression/Carrier Suppression
  • Insertion Loss: Tx Loss/Rx Loss


D-STAR is a new ham radio system which offers digital voice and data communication. It connects repeater sites over the Internet and forms a wide area ham radio network. The DSTAR system provides a new capability and functionality to the ham radio world and increases the efficiency of emergency communications.

Where do TXRX systems products come in?
D-star systems are being configured all over the world. Sites may be comprised of VHF, UHF, 1.2 GHz or a complete system including all bands. TXRX offers various products to handle the signal management issues for these repeater site installations.

Duplexers for 28-37-02A (VHF), 28-66-02A (UHF) and 28-97-01A (1.2 GHz) as well as the new 36-97-07053-A, 1.2 GHz Triplexer which allows the use of a single 1.2 GHz antenna for the Tx, Rx, and a high-speed Data channels.

For sites in need of using only a single feedline for VHF/UHF, TX RX Systems manufactures Crossband Coupler models 80-05-06 and 80-05-07 handling up to 250W per band.


Duplexer Problems and Remedies
Duplexer Selection Guide


Product Specifications 
Item No28-37-02A
Item Name144-174 MHz, Duplexer
Frequency Range144-174 MHz
Minimum Freq Separation0.5 MHz
Power Rating400 W
Isolation85 dB
Insertion Loss1.5 dB
Number of Cavities4
Cavity Size6.625" Dia.
Impedance Ω50
Dimensions H x W x D33" x 19" x 15"
Tx-Rx Port ConnectorsN
Antenna ConnectorsN
Temperature Range-30 to +60 °C
Shipping Weight50 lbs.

Compatible Devices:

Image of a 28-37-04A Duplexer

442-450 MHz, Duplexer

Image of Duplexers

1215-1300 MHz, Duplexer