DFS Channels: Why Your 5GHz Wi-Fi Randomly Disconnects

You bought a high-end router, set it to 160MHz width for max speed, but it keeps dropping to 20MHz or disconnecting. The culprit is not the router; it is the law.

1. Shared Spectrum with Weather Radars

The 5GHz spectrum is not exclusively for Wi-Fi. A huge chunk of it (UNII-2 channels 52-144) is shared with Military and Weather Radars. By law, if your router detects a radar pulse, it MUST silence itself instantly and jump to a non-DFS channel.

2. The "Pre-CAC" Wait

When you reboot a router on a DFS channel, it cannot broadcast immediately. It must listen for 60 seconds (Channel Availability Check) to ensure the air is clear. This is why your 5GHz SSID takes forever to appear after a reboot.

Pro Tip: If you value stability over raw speed, manually set your channel to 36, 40, 44, or 48 (UNII-1). These are non-DFS and never disconnect.