Bird 4431 – Variable Tap RF Wattmeter

• Same as the Model 43 except for an RF signal sampler probe
• Elements required for operation / sold separately – see below for selection information
• Modulation: CW, AM, FM and analog TV
• Measurement: average RF power
• Frequency range: 2MHz to 1.2GHz

The Bird 4431 RF Sampling Wattmeter is the same as the Bird 43 Thruline Wattmeter except for an RF signal sampler probe.

The RF sampler provides a low-power sample of the signal being transmitted through the wattmeter’s line section. This signal is available at the female BNC connector labeled “RF SAMPLE”, on the right side of the housing. The signal level can be set with the control knob on the front of the meter. The table below lists approximate attenuation levels and notes the maximum suggested adjustment. The sampler output may be fed to any suitable RF signal monitoring device, such as a frequency counter, spectrum analyzer, or oscilloscope. All other operations are the same as the Bird 43.

The RF line section is precision machined to provide the best possible impedance match to the transmission line under test. A formed phosphor bronze spring finger protrudes into the element socket to make contact with the element.

At each end of the line section are Bird Quick-Change RF connectors that may be interchanged with any other Bird “QC” connector. The wattmeter housing does not interfere with connector changes.

To make measurements, a Bird Plug-In Element is inserted into the line section socket and rotated against one of the stops. A small catch in the corner of the socket face presses on the shoulder of the element to keep it in proper alignment. This assures good contact between the spring finger and the element contact and between the lower edge of the element and the line section body.

The Bird 4431 is compatible with a large number of elements, covering a wide range of frequency and power ratings.

Compatible elements can be viewed by clicking here and viewing tables 1, 2, 3, 4, 6, 13, and 14.

Please note, elements are sold separately.

All Bird plug-in elements are calibrated in accordance with meticulous Bird calibration procedures supported by a long history of mean deviation values to assure adherence to advertised specifications of current instruments, as well as field interchangeability with equipment purchased, used, and trusted in all the years since its introduction.

At each end of the line section are Bird Quick-Change RF connectors that may be interchanged with any other Bird “QC” connector. The wattmeter housing does not interfere with connector changes. The Bird 4431 is normally supplied with Quick-Change Female N-type connectors.

The chart below contains descriptions and part numbers for many types of optional QC connectors.

Bird offers several versions of its 44/APM-16 series wattmeter. The chart below provides a brief overview of the main differences in each. Please click here for more detailed information on Bird’s power meter line.