Test Equipment

The TD-3 test equipment for routine maintenance and troubleshooting procedures is designed to match the high performance of the TD-3 system and is simple and convenient to operate. The units have good long term stability and may be readily interconnected for testing or self-calibration. This is desirable because much of the TD-3 equipment is located in remote, unmanned sites where testing time must be kept to a minimum. The equipment consists of a transmitter-receiver test set mounted in a rolling console and an FM terminal test panel mounted in (and used with) the existing TD-2 FM terminal test set. The major functions of the test set are to measure amplitude and return loss in the 3700 to 4200 MHz (RF) and the 50 to 100 MHz (IF) frequency ranges, AM noise figure, frequency, and RF and IF power. These are similar to the functions of other test consoles,1-2 but significant advances have been made in implementation. Solid state devices and RF coaxial instrumentation made such advances possible. Accurate IF frequency markers, low level power measurements, and direct reading frequency measurements are used extensively. The FM terminal test panel is designed to enable the TD-2 FM terminal test set to test TD-3's 3A FM terminals. A major influence to this approach was that the 3A terminals3 are now standard equipment in TD-2 production and are replacing TD-2 terminals in the TD-2 improvement program. Because many 3A terminals are being 1459