Multifunction Power Meter


The Model 4421A is a Multifunction Power Meter to be used combination with Bird’s Precision Power Sensors to display RF power readings with up to 1% accuracy. This intuitive display unit clearly identifies the Forward and Reflected power measurements within the RF path. In addition, return loss readings can also be shown to provide additional insight into the RF system being monitored.

The 4421A is the next generation replacement for the industry standard Model 4421. Building upon the original model’s high level of accuracy and its ease of use, the new 4421A enhances the meter’s functionality by utilizing a smaller/lighter design, by providing the ability to have dual sensor inputs and by displaying time plots of the power measurements.


  • Compatible with the full line of Bird’s 402x-series power sensors.
  • Automatic sensor detection for seamless integration.
  • Large 9.7″ full color LCD touchscreen display for easy readability.
  • Dual sensor option expands measurement capabilities.
  • Compact, lightweight and portable design enhances funtionality.


  • Forward Power in W or dBm
  • Reflected Power in W or dBm
  • Return Loss in VSWR, RL, or Reflection Coefficient
  • Graph of Power in W over time


Bird Technologies

Bird® Leader in Radio Frequency Products and Services

4421A datasheet