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Model 43 THRULINE® Directional Wattmeter
(DAI Part# 43N)
The Model 43 THRULINE® Directional Wattmeter accurately measures forward or reflected power in coaxial transmission lines under any load condition. Each Model 43 consists of a line section, "QC" (Quick Change) connectors and an indication meter housed in a rugged, corrosionresistant aluminum case.

The line section is a high-precision 50 OHMS coaxial air line that inserts between the transmitter and the antenna or load. A socket is provided in each line section for a plug-in element with the desired power rating and frequency range. Line section ends are equipped with "QC" -type connectors.

The model 43 is supplied with two female "n" -type "QC" connectors. These connectors can be interchanged in the field without affecting instrument calibration.

The Instrument's indicating meter is a shock-mounted 30-microampere meter with scales of 25, 50, and 100; permitting full-scale direct-power reading from 100 milliwatts to 10,000 watts.

Plug-in elements determine the power rating and the frequency range, and these values are marked on each element. The elements rotate to read both forward and reflected power. There is no need for calibration charts or instrument adjustments. Elements can be purchased at any time and replaced in the field. For added convenience, Model 43 connectors and elements are interchangeable with many other Bird wattmeters.

Remote installation can easily be achieved by removing the Model 43's RF line section and inserting it at any desired point in the line. For best visibility, the meter itself can be relocated using the 32" meter cable supplied in the instrument housing. Additional meter cable lengths can be ordered separately.

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STANDARD ELEMENTS
Power Range 2-30 25-60 50-125 100-250 200-500 400-100
5W -- 5A 5B 5C 5D 5E
10W -- 10A 10B 10C 10D 10E
25W -- 25A 25B 25C 25D 25E
50W 50H 50A 50B 50C 50D 50E
100W 100H 100A 100B 100C 100D 100E
250W 250H 250A 250B 250C 250D 250E
500W 500H 500A 500B 500C 500D 500E
1000W 1000H -- 098032-0100 1000C 1000D 1000E
2500W 2500H -- -- -- -- --
5000W 5000H -- -- -- -- --