Bernie asked 1 month ago
My esp32 devkit board is located in a room full of grounded plumbing so that the wifi signal barely reaches it. How do I improve wifi sensitivity for reception and transmission? Can I attach an external antenna?
In the following question, I am not sure where the zero-ohm resistor is on the internal antenna pad?
Sara Santos Staff answered 1 month ago
Hi.
Yes. You can use an external antenna.
Are you using an ESP32-CAM? Then, this is the guide you’re looking for: https://randomnerdtutorials.com/esp32-cam-connect-external-antenna/
Regards,
Sara
Bernie answered 1 month ago
Not for ESP32-CAM. Just a DOIT Devkit V1 without an antenna jack.
There must be a way to improve reception/transmission?
Do You know what Steve Mercer means by “removing zero ohm resistor”?
Sara Santos Staff answered 1 month ago
Hi again.
The zero ohm resistor is on the ESP32-CAM.
So, it doesn’t apply to your case.
If you’re using an ESP32 DOIT board, it is not that easy, but I found this tutorial that shows how to solder an external antenna: https://community.home-assistant.io/t/how-to-add-an-external-antenna-to-an-esp-board/131601
There are also ESP32 board models that already come with an antenna connector, so you just need to plug the antenna. Those might be a better option if you don’t want to solder.
Regards,
Sara
Bernie answered 4 weeks ago
So I implemented Sara’s link and managed to improve signal strength by about 10 dB. It went from -93 to -83 dB.
What I did was to solder a wire to the RF output of the module, as my 38 pin ESP32 did not have an antenna jack. I experimented quite a bit and concluded that there is no need to extend the ground wire. Looking at the built in antenna, you see what appears to be a ground copper trace that loops back to the RF output. Then the micro built-in antenna takes off from where the RF joins ground. So I cut the ground trace and the trace to the built-in antenna.
Experimentation shows that the longer the antenna, the better the signal. So the wire I attached is 50 cm which is 4x the wavelength of 2.43 GHz. Cutting a longer wire by a cm each time, I could see that some multiple wavelengths are about 4 dB stronger than non-integral lengths.
Also it turns out that signal strength is very sensitive to how this long antenna is physically laid out. I still think I could use some kind of an RF amplifier, if I could find one.
Bernie
Sara Santos Staff answered 4 weeks ago
Hi.
Thanks for your feedback.
I’m glad it worked somehow in improving the signal, even though not that much.
Regards,
Sara