Final answer:
The ARSR-4 radar typically uses a single beam that can scan in both elevation and azimuth, not multiple 2-degree elevation beams. For a 500-MHz radar system, the smallest observable detail is around the size of its wavelength, which is approximately 60 cm.
Step-by-step explanation:
The ARSR-4 (Air Route Surveillance Radar Model 4) does not use multiple 2-degree elevation beams. Instead, it typically utilizes a single beam that scans in elevation as well as azimuth. The question about the smallest observable detail with a 500-MHz radar is a separate radar specification and is not directly related to the ARSR-4's beam configuration. However, to answer the second question, the smallest observable detail with a 500-MHz radar will depend on various factors including the radar cross-section, target shape, and signal processing techniques.
Generally, radar wavelength is the determining factor, where shorter wavelengths can detect smaller objects. Since the frequency is inversely related to the wavelength, a 500-MHz radar which corresponds to a wavelength of approximately 60 cm can typically detect features that are around this size or larger.