Thanks for the test you did.
I did replace 2 faulty units’ chip antenna with solid core copper wire.
One with 0.25mm gauge and another with 0.5mm gauge. Both gave me the same amount of signal quality; and with values comparable to other ESP boards with working antenna designs.
I tried 31.25mm as well but I had no signal whatsoever.
So 62.5mm it is.
Thanks alot!
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Thanks for the community brainstorm !
With 62mm wire I get +6/7dbm RSSI
Wouldn’t it be better to desolder the ceramic antenna c3?
This solution only enabled the device to create an AP, and it never connected upon configuration. The struggle is not worth
I’d instead go for Carenuity C3-Mini:Carenuity Original C3-Mini v2.2.1 – IoT Development Board – Chipglobe
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Hi all, I’ve performed a similar experiment to boost the RSSI/Power of ESP32 C3 Super Mini.
My focus was to make C3 super mini usable in a larger home and try to fit in my existing 3D printed case with minimum modifications instead of spending days on RF engineering.
So I’ve decided to go ahead with a multi-stranded copper wire available on my shelf, with a wire length of around 61-62mm. Created a simple loop like a spring by winding it over a screw-driver. I believe that the spring like (somewhat helical?) antennas typically perform well for omni-directional radiation patterns.
I’ve placed another ESP32 C3 Super Mini with ceramic antenna (Without any mod) next to this setup. Then I placed both these units behind my sofa before turning them on to simulate a “weak” wifi network condition.
Here is the dashboard I’ve created using ESPHome that shows the result of this experiment.
- Average RSSI and dBm power increased by ~15dBm.
- Internal chip temperature of ESP dropped by a few degrees. (Better impedeance matching and power transfer of the antenna?)
Feel free to take a look and discuss this further if needed. I’ve decided to buy a dedicated 2.4GHz antenna by AntennaHome and give it a try as well. Will update the experiment further once I try it out.
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In continuation of the above experiment, this time I’ve quickly added a cheap 25-30 AWG multi-stranded Aluminium cable to another ESP32 C3 Super Mini, which was in my 3D printed case.
The below image shows change in RSSI once the modification is done. The Mod was done at 9 PM so observe the orange line before and after 9 PM (Updated every 5 mins in my actual firmware, so not as detailed as yellow/blue lines)
Seems like the antenna mod is a promising hack to enhance the poor on-board ceramic antennas on ESP32-C3 Super Mini dev kits.
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Have you also tried a quarter-wavelength antenna to see if it makes much difference? Should be around 31mm in length. Asking because you’re using a half-wavelength as monopole now.
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I didn’t tried 31 mm yet
But read somewhere that λ/4 requires a good ground plane which is not proper in esp32-C3 super mini. However, λ/2 don’t require a ground plane.
Maybe that’s why it works. @robertklep
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My antenna knowledge is extremely limited, and if it works, it works 
I always thought that half-wavelength antennas needed to be used in a dipole setup to function optimally.
Antenna design is black magic…
Lookin at antenna @robertklep posted, I suspect that the pad where the vertical element joins to ring, is connected to PCB ground. So it’s little bit like inverted F antenna (shorted to gnd at one point)?
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Dear All,
I had the same problem with my C3 modules using ceramic antennas. The connection was very unstable. After internet survey I decided to remove a ceramic antenna and solder a simple 32mm wire (quarter wave). The signal improved from -80dB to -67dB.
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