How to get my phone to access WIFI channel 13?

Question

My phone can't see Wifi 2.4 Channel 13. Why? How can I fix it?

I have an android phone (Moto E4, Android 7.1.1, Not rooted) that was purchased in the US about 12 months ago. Just after purchase,I came to China for a few months, and it worked perfectly on the Wifi here in my home. I had a Chinese sim card. I don't know what channel my home Wifi was working on last year.

In September, I returned to the US and swapped out the sim card for a US carrier. It continued to work perfectly.

I have just now returned to China, and my phone no longer can see the wifi signal in my home. When I look on my PC, it shows that the Wifi is transmitting on channel 13. When I look in my android app "Wifi Analyzer" it shows a blank space for channel 13. (Also, I forgot my Chinese sim card in the US)

Is this a hardware or a software issue? How to fix this?

Answer 1

My phone can now detect ch 13 on 2.4 GHz wifi.

Here's how I did it. I borrowed a local sim card. As soon as the phone booted up, if was able to see the wifi signal. I confirmed that it indeed was on ch 13 with both wifi analyzer and on my pc.

I have since removed the borrowed sim card, and the phone continues to see channel 13. So indeed, as suggested in the comments by @Robert,

auto detection of the country you are in e.g. via used SIM card

Is the correct answer.

Answer 2

WiFi Channels are a regionally/country regulatory issue.

In the United States the 2.4 GHz bands are 1 through 11.

You can either:

• Change your router's 2.4 GHz band to fit the U.S. firmware/ROM limitations.
• Switch to using a router on the 5 GHz band as there is overlap with China and the United States.
• Risk bricking your phone with a Custom ROM. Note that the Moto E4 appears to have only U.S. and European versions, and each version is using a different CPU manufacturer so trying put International ROM on a U.S. phone would not work and may brick the device.