81-55X-26 Series

Image of Isolators

81-55X-26 Series


81-55X-26 Series, 300-400 MHz, Dual-Junction Circulator and Isolators are designed to provide the specified isolation under continuous duty at maximum power. Their conservative, rugged design and construction have a record of excellent reliability and high performance established through over 20 years of service in critical systems.


  • Provides rated isolation at rated continuous power
  • Standard isolator loads rated to protect against antenna system failure


  • Available dual or single junction versions from 118-250 MHz, 300-530 MHz and 746-960 MHz
  • Small package outline
  • Up to 250 watts power handling
  • High isolation throughout bandwidth (no-tuning)
  • Low insertion loss
  • Low PIM Design
  • Wide operation temperature range
  • RoHS compliant
  • Various connector options available
  • Ideal for applications with minimal guard band between transmit and receive frequencies

81-55X-26 Series, Dual Junction Circulators and Isolators

Model Isolation BW
81-55A-26-XX* 300-350 MHz
81-55B-26-XX* 350-400 MHz

xx = load: 50 = 25 watts, 60 = 60 watts, 100 = 100 watts
** load dependent
*** Isolators with a bandwidth greater than 25 MHz


Product Specifications 
Item No81-55X-26 Series
Item Name300-400 MHz, Dual-Junction Circulator and Isolator
Isolation BandwidthSee Above Model Matrix
Number of Junctions2
Isolation46 dB***
Insertion Loss0.44 dB
Return Loss21 dB
PWR - FWD-RFL250/**
Temperature Range-30 to +60 °C
Connector TypePorts 1-3: N (F), Port 4: 10W
Dimensions H x W x L0.87" x 4.17" x 2.28"
(22.0 x 106.0 x 58.0 mm)
Tolerance±0.1 mm, ±0.01 inch