Meaning
Regulatory signals emitted by meteorological and military installations require wireless devices in the 5 GHz band to vacate the channel immediately upon identification. A dynamic frequency selection radar pulse consists of a specific sequence of bursts that the radio receiver must recognize during its channel availability check. If the hardware detects these patterns, it marks the frequency as unavailable for a set period.
Detection Window
Listen intervals occur both before the network starts and during active operation to scan for interference. The duration of this period is typically sixty seconds for most channels but increases to ten minutes in weather radar bands. A device cannot transmit until it completes a full scan without seeing a single pulse.
This window is a mandatory part of the startup sequence for any equipment using shared radar spectrum.
Channel Vacancy
Radio equipment must move all associated clients to a different frequency within ten seconds of a confirmed hit. This rapid transition avoids interfering with primary users who have priority access to the spectrum. The system then enters a non-occupancy period where it avoids the flagged channel for thirty minutes.
Compliance Burst
Laboratory testing uses synthetic waveforms to verify that the hardware can distinguish between legitimate data and a radar signature. These test pulses vary in width, repetition interval and count to simulate different radar types. Failing to identify a single burst in a sequence results in a certification rejection.
