Final answer:
Minimum VOR reception altitude varies based on the VOR station's service volume category. The FAA provides reception ranges for terminal, low, and high altitude VORs, with high altitude VOR reception potentially reaching up to 60,000 feet.
Step-by-step explanation:
The question seems to reference VOR (VHF Omnidirectional Range) reception which is related to aviation navigation, and appears to contain a fragment of the Rayleigh criterion formula for optical resolution. While there may be some confusion, typically the minimum altitude for VOR reception depends on the distance from the VOR station and its service volume, rather than an optical resolution formula. The FAA (Federal Aviation Administration) publishes altitude recommendations as part of their Standard Service Volumes for different classes of VOR stations, which define the usable range of altitude and distance from the station itself. For terminal VORs, the reception range typically extends to 25 nautical miles up to an altitude of 12,000 feet; for low altitude VORs, the range is up to 40 nautical miles for altitudes up to 18,000 feet, and for high altitude VORs, the range can extend up to 130 nautical miles for altitudes ranging between 14,500 feet to 60,000 feet. Pilots rely on these guidelines to ensure they remain within a VOR's coverage area for navigation.