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I'm Getting WiFi Stability Issues on My ESP32-S3 Board

Key Issue​

The origional P4 and P7 revisions of Unexcpected Maker ESP32-S3 boards (pre 2024) may experience instability when using a WiFi channel lower than 6, especially when using full TX power and when native USB is enabled.

This affects:

  • Connecting to WiFi access points on low channels
  • Operating an access point on low channels
  • Using ESPNow with low channels

Solutions​

You can resolve these issues by either:

  1. Using WiFi channel 6 or higher
  2. Reducing TX power to 75-90%
  3. Or combining both approaches

Will reducing TX power reduce my range?​

It will, but not as much as you might think. Most applications won't see any range related issues at 75%.

Later Revisions​

The P8 revision boards resolved the low-channel issue and improved the overall radio performance by introducing a new Antenna, and implementing an alternate RF matching network with a broader bandwidth range, though with a slightly reduced signal gain.

Alternate u.FL versions were also introduced fro those that wanted to extend their radio range by using an external antenna.

Series[D] Boards​

Series[D] board were recently instroduced that incliude both the u.FL connector and on-board antenna on the same board, with a digitally controlled RF switch that allows you to select your antenna option in code.

RF Performance on the Series[D] boards is on par with the P8 revisions, though the ESP32-S3 full power TX mode can oscilate which can stop the RF switch from working.

If you expereince connectivity issues (TX) with your Series[D] boards, try reducing your TX power to a lower setting.

For example:

Arduino:

#include <WiFi.h>

void setup() {
  WiFi.mode(WIFI_STA);
  WiFi.begin("ssid", "pass");

  // After WiFi is started/connecting is safest:
  WiFi.setTxPower(WIFI_POWER_15dBm);   // pick a lower level
}

Common levels you can use:

  • WIFI_POWER_19_5dBm (default)
  • WIFI_POWER_15dBm
  • WIFI_POWER_11dBm
  • WIFI_POWER_8_5dBm
  • WIFI_POWER_7dBm
  • WIFI_POWER_5dBm
  • WIFI_POWER_2dBm
  • WIFI_POWER_MINUS_1dBm
wifi-issues wifistability txpower tx-power