ESP32-C5 SoftAP band changes when STA switches bands – need AP band to remain fixed
Posted: Tue Dec 30, 2025 8:11 am
Hello,
I am working with ESP32-C5-WROOM-1 (N16R4 / N16R8) using the Arduino ESP32 core v3.3.5 on Arduino IDE 2.3.7, running in AP + STA mode.
### Requirement
My design requires the SoftAP band to remain fixed, regardless of any band change on the STA interface.
Specifically:
* SoftAP should stay on 2.4 GHz
* STA may connect to 2.4 GHz or 5 GHz
* STA band switching must not affect the SoftAP band
### Current Behavior
What I am observing now:
1. ESP32-C5 starts SoftAP on 2.4 GHz
2. STA connects to a 5 GHz network
3. After successful STA connection, the SoftAP disconnects
4. Investigation shows that the SoftAP band switches to 5 GHz, matching the STA band
5. This causes disconnection of a monitor device that is permanently connected to the AP
### Why this is a problem
The monitor device relies on the SoftAP connection to:
* Receive Wi-Fi test feedback
* Confirm network validation with messages like “Wi-Fi test success”
When the SoftAP band switches, the monitor device disconnects, breaking the test flow and user feedback mechanism.
### Questions
1. Is it technically possible on ESP32-C5 to keep the SoftAP band fixed while allowing STA to switch between 2.4 GHz and 5 GHz?
2. Is the observed behavior a hardware limitation of ESP32-C5 RF architecture, or a software/driver limitation?
3. Are there any APIs to:
* Detect the current SoftAP band at runtime?
* Prevent or override SoftAP band switching?
4. If independent band operation is not supported, what alternative architecture or workaround is recommended to maintain a stable AP connection for the monitor device?
Any clarification on chipset limitations, supported coexistence modes, or recommended design patterns would be greatly appreciated.
Thank you for your support.
I am working with ESP32-C5-WROOM-1 (N16R4 / N16R8) using the Arduino ESP32 core v3.3.5 on Arduino IDE 2.3.7, running in AP + STA mode.
### Requirement
My design requires the SoftAP band to remain fixed, regardless of any band change on the STA interface.
Specifically:
* SoftAP should stay on 2.4 GHz
* STA may connect to 2.4 GHz or 5 GHz
* STA band switching must not affect the SoftAP band
### Current Behavior
What I am observing now:
1. ESP32-C5 starts SoftAP on 2.4 GHz
2. STA connects to a 5 GHz network
3. After successful STA connection, the SoftAP disconnects
4. Investigation shows that the SoftAP band switches to 5 GHz, matching the STA band
5. This causes disconnection of a monitor device that is permanently connected to the AP
### Why this is a problem
The monitor device relies on the SoftAP connection to:
* Receive Wi-Fi test feedback
* Confirm network validation with messages like “Wi-Fi test success”
When the SoftAP band switches, the monitor device disconnects, breaking the test flow and user feedback mechanism.
### Questions
1. Is it technically possible on ESP32-C5 to keep the SoftAP band fixed while allowing STA to switch between 2.4 GHz and 5 GHz?
2. Is the observed behavior a hardware limitation of ESP32-C5 RF architecture, or a software/driver limitation?
3. Are there any APIs to:
* Detect the current SoftAP band at runtime?
* Prevent or override SoftAP band switching?
4. If independent band operation is not supported, what alternative architecture or workaround is recommended to maintain a stable AP connection for the monitor device?
Any clarification on chipset limitations, supported coexistence modes, or recommended design patterns would be greatly appreciated.
Thank you for your support.