F. Radar and Optical Tracking
Because of their limited range, ground radar sets and theodolites were only of minor value in tracking balloons. Sets such as the SCR-584, the SPM-1, and MPS-6 are suggested when the balloon is expected to remain within the 60 to 80 mile range.
VI. INSTRUMENTATION
A. Altitude Determination
To provide accurate, sensitive and readable records of the pressure (altitude) encountered by the balloon, various systems have been tried. A modified radiosonde-type aneroid pressure capsule (Signal Corps ML 310-/) has been the basic sensing element, but three different systems of modulation of the radio signal as a function of pressure have been used.
(1) Standard Diamond-Hinman Radiosonde Pressure Modulator
Seen in Figure 29, the standard Diamond-Hinman radiosonde system provided first pressure sensor used. As the pen arm is pushed
Figure 29. Schematic diagram, Diamond-Hinman radiosonde system.
across the commutator by the aneroid capsule, it falls on alternating insulators and conductors attached to three circuits.