Bad WiFi reception with multiple different ESP32 dev boards

[bbernhard]

Hello everybody,

I recently bought a couple of ESP32 development boards in order to measure the WiFi throughput (see this reddit post for details). In total I've tested about 7 boards from 3 different vendors (including some boards from espressif).

While doing that, I've noticed that most of the dev boards have a pretty bad WiFi reception. My access point is about 2 metres away and other devices are working fine, so I am pretty sure the access point is not the culprit here. For the boards with an internal antenna, I could significantly improve the WiFi reception by soldering a SMA connector to it (similar to what is shown in this video here: https://www.youtube.com/watch?v=-8hxk81H6QI). By just soldering the SMA connector onto the board, the rssi impoved from -80 to -45.

I've also bought some boards with the ESP32-WROOM-32U microcontroller (e.g. the ESP32-DevKitC-32U dev board). With the ESP32-DevKitC-32U dev board, I am reading a rssi of -82 without an external antenna. With an external antenna (I used this one here, the rssi improves to -66, which is better but still worse than the ugly "SMA connector hack" from above. This comes pretty surprising to me - I really thought that the ESP32-WROOM-32U with an external antenna will be performing the best.

Has anyone an idea what's going on here? Am I using the wrong antenna or am I missing something here?

Thanks for your help!

Kind Regards,
Bernhard

[bbernhard]

Does nobody have any suggestions on how to improve the WiFi reception?