The Bird TERMALINE 82A is a general purpose coaxial load resistor to be used in conjunction with transmitters which have an RF output up to 500 Watts, over an extended frequency range of DC to 3.5 GHz. This coaxial load resistor is designed to match commonly used 50Ω coaxial transmission lines. The impedance is quite independent of frequency, and is almost a pure resistence. On the production units, the voltage standing wave ratio (VSWR) values are maintained below 1.1 to 1.0 up to 1000 MHz. VSWR determinations for the particular resistor are tabulated on an individual test tag attached to each unit. Calibration is not normally performed for frequencies from 1000 to 3500 MHz, but experience shows that units checking good will be within specification in the upper range.
Below 50 MHz, the input impedance of the TERMILINE is very nearly a pure resistance value. The production tolerance on the dc resistance is ±3% from the nominal 50Ω, and measured exact values for this particular resistance are also given on the test tag.
Any Series 82 load resistor may be made to operate as a termination type wattmeter with the insertion of a Bird Model 43 THRULINE Wattmeter in series with the load. This will permit measurement of forward power within the usual capabilities of the TERMALINE and the THRULINE Wattmeter.