Bird - The RF Experts

Multifunction Power Meters

Dual Sensor Inputs

4421A Series, Multifunction Power Meters used in 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 Series 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
Product Selection Guide
Model Number # of Sensors Communication Port
4421A-10-00-0 Single 402x Sensor No
4421A-20-00-0 Dual 402x Sensors No
4421A-10-11-0 Single 402x Sensor RS-232
4421A-20-11-0 Dual 402x Sensors RS-232
product specifications:
Item No
Item Name
Multifunction Power Meter
Compatible Bird Power Sensors
4021, 4022, 4023, 4024, 4025, 4027 Series and 4028 Series
Power Range
Sensor dependent
Frequency Range
Sensor dependent
Sensor Channels
Model dependent: 1 or 2
VSWR Display
1.0 to 199.9
Return Loss Display
0 to 40 dB
9.7" TFT full color LCD with touch screen
AC Power
100-240VAC, 50-60Hz, 30 W
Fuse Rating: 1A, IEC (5 x 20mm), Time-Delay
Type: Internal, rechargeable
Life: Up to 8 hours
Changer: Built-in. Approximately 4 hours to fully recharge.
Model dependent: RS-232, LAN
95% max (noncondensing)
10,000 ft. (max)
Operating: 0 to 50 °C
Storage: -20 to 70 °C
10.6" x 9.7" x 3.6"
(269 x 246 x 91 mm)
Less than 5 lbs., 2.3 kg
compatible devices:
4020 Series
3% Accurate, Directional Power Sensors
4027A Series
1% Accurate, Precision Directional Power Sensors
4027F Series
1% Accurate, Filtered Power Sensors
4028 Series
2% Accurate, Precision Power Sensors
Latch-N-Lok Interface Cable