DESIGN OF A BALLOON-BORNE DUAL CAVITY MICROWAVE REFRACTOMETER.
Abstract
Design fabrication details and laboratory test results for five experimental model refractometers are given. The design objective is an expendable refractometer having 2 N unit accuracy, weighing 3 lbs or less, for addition to radiosondes such as AN/AMQ-21, being compatible with Rawinsonde ground equipment AN/GMD-1 and AM/GMD-2. The refractivity sensors are two 1750 Mc resonant coaxial cavities, one evacuated, the other ventilated. An oscillator swept linearly past the cavity frequencies produces output pulses having duration proportional to cavity resonant frequency difference, hence proportional to refractivity. The dual sensing cavities are machined from a single bar of aluminum for similar response to changes in cavity temperature. High diffusivity minimize the duration of thermal transients. Linearity error is less than 1 N unit with variable pressure at constant temperature. Tests show the magnitude and duration of transient temperature induced refractometer errors when both cavities are evacuated. Temperature tests with the sampling cavity ventilated have not been made.
Document Details
- Document Type
- Technical Report
- Publication Date
- Sep 01, 1965
- Accession Number
- AD0484063
Entities
People
- William T. Dickinson
Organizations
- ARCO