Bird 4391A – RF Power Analyst (PEP-Dual Element)

• Designed for air navigational aids DME, ATC, and other pulsed RF systems such as telemetry, radar, and more

• Elements required for operation / sold separately – see below for selection information
• Modulation: CW, Pulsed RF
• Measurement: Peak envelope, peak pulsed, average RF power
• Frequency range: 0.45 – 2700 MHz (element dependent)

The Bird 4391A RF Power Analyst is an insertion type digital RF Directional Thruline Wattmeter designed to measure peak or average power flow, load match, and amplitude modulation in 50 ohm coaxial transmission lines. It is intended for use with CW, AM, FM, SSB, TV, and Pulse modulation envelopes. The instrument directly reads PEP or CW power in watts, milliwatts, or kilowatts in 9 ranges from 2.5 to 1000 full-scale forward power and 0.25 to 100 full scale reflected power depending on the Plug-in Element. In addition it reads SWR directly over the range of 1.00 to 99.99, percent modulation directly over the range of 0.0 to 99.9, and return loss over the range of 0 to 36.1 dB. For convenience, forward and reflected CW power can be displayed in dBm (dB above 1 milliwatt) from 6 dB above to 24 dB below nominal element range.

Power range and frequency band are determined by the Plug-in Elements used. Two switches on the front panel of the instrument are set by the user to correspond to the nominal power range of the forward element. The reflected element is assumed to have a nominal range one tenth that of the forward element.

In any mode of operation, the instrument can recall from memory the lowest or highest reading taken or tell the operator whether the newest reading is less than, equal to, or greater than the previous reading.

The Model 4391A contains a short section of rigid 50 ohm coaxial air dielectric transmission line. To make measurements relating to the traveling waves in a coaxial line, that line must be disconnected at some convenient point to permit the Model 4391A air line to be inserted.

Although the Model 4391A is normally supplied with two Female N-type connectors, a variety of easily interchangeable connectors are available to facilitate connecting to the user’s system.

Once the Model 4391A is installed in the coaxial line, a Plug-in Element or a pair of Plug-in Elements must be selected which correspond to the frequency and power levels to be measured.

In order to take full advantage of the Model 4391A’s capabilities, two elements in a 10:1 ratio of power range should be used. If only one element is used, the other socket should be filled with a dust plug or a higher power element. Also, for greatest accuracy, the element(s) should be chosen having the lowest possible power range that will not result in over-ranging.

The Bird 4391A 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 43 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 the 43 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.

*An asterisk in the chart above for RF power and frequency range indicates that this value is dependent on the Bird element being used.