2nd 5Ghz Wifi band switches automatically after a couple of hours or at most a day to 40Mhz asus router
  There could be several reasons why your 2nd 5GHz WiFi band is switching automatically to 40MHz after a couple of hours or at most a day on your ASUS router. Here are some possible causes and solutions:

1. Firmware issue: Check for the latest firmware updates on your router and apply them if there are any. Outdated firmware can cause unusual behavior, including automatic band switching.
2. Channel interference: Check for other devices in your area that might be causing interference with your router's 5GHz band. Other devices operating on the same channel as your router can cause signal degradation and force the router to switch to a different channel. You can try changing the channel on your router to see if that resolves the issue.
3. Router settings: Check your router's settings to see if there is an option to disable automatic band switching. Some routers have this option in the advanced settings.
4. Network congestion: If there are too many devices connected to your router, it may cause network congestion, leading to slower speeds and automatic band switching. You can try disconnecting some devices and see if that resolves the issue.
5. Wireless interference: Other wireless networks in your area could be causing interference with your router's 5GHz band. Try disabling the 5GHz band on
If your ASUS router's 5GHz band is automatically switching to 40MHz from a higher bandwidth setting (like 80MHz), it could be due to several factors. Here are some troubleshooting steps and considerations to help resolve the issue:

1. **Check Router Settings:**
   - Log into your router's web interface (usually accessible via a web browser at 192.168.1.1 or 192.168.50.1).
   - Navigate to the **Wireless** settings and ensure that the 5GHz band is set to 80MHz. 

2. **Firmware Update:**
   - Ensure your router's firmware is up to date. Manufacturers often release updates that fix bugs and improve performance. Check the ASUS support website for the latest firmware version for your specific router model.

3. **Interference:**
   - The 5GHz band is less crowded than 2.4GHz but can still experience interference from other devices (like microwaves, cordless phones, etc.) and networks. If the router detects significant interference, it may automatically switch to a lower bandwidth to maintain a stable connection.

4. **Channel Selection:**
   - In the wireless settings, try setting the channel for the 5GHz band to a fixed channel instead of "Auto." Use a less crowded channel for better performance. You can use Wi-Fi analyzer apps to check channel congestion.

5. **Dynamic Bandwidth Adjustment:**
   - Some routers have a feature that dynamically adjusts