Sadly I didn’t think to get a “before” signal reading. I do know, that I could barely get the unit on the network before the antenna mod due to the metal case of the floodlight. The tasmota signal strength bars showed 1 bar. Afterwards its doing fine sitting around -68dbm and full bars. I’ve got one more I want to do and I’ll do a before and after for that and update this thread.
As far as the ground / signal question. I severed and removed a section of the antenna trace leading to the printed antenna, disconnecting it fully, then scraped off the mask on the board where the surface mount connector would need to be grounded. I also then used the overlap of the UFL ground lead to bridge the printed antenna into the ground plane on the board in hopes to prevent any possible interference.
It will be great if you post the latest pictures of your mod. But I understand if you can’t. Thanks again for the info
@tom_l
Thank you for this - just copied and made a massive difference - using a USD0.26 antenna!.
Signal has gone from 40% to 60%
Attached photo of modification and also connection strength before and after the mod (measurements taken in final position after adding hot glue to strengthen and put in a upvc enclosure).
Cheers.
Details:
- ESP32 mini - outside of the house being used to drive WLED, 2xws2812b strips with sacrifical leds, and an IR receiver
- Antenna - ESP8266 ESP32 S WiFi Bluetooth Module with 2.4G IPEX Wireless Antenna for Arduino|Integrated Circuits| - AliExpress
Has anyone added an external antenna to a Sonoff TH16?
I don’t have a TH16 but found a thread which appears to show where the connections are on the board to add one:
Hope it helps.
thank you !!
Hello,
I have ESP32 (https://www.amazon.ae/gp/product/B086ZMDB7H/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1) using it for Mi flora bluetooth, but the bluetooth range is too short, will the above mentioned hack by putting external antenna improve the bluetooth range or thats just for Wifi range?
Thanks.
Yes it will help. The ESP32 uses the same antenna for both wifi and Bluetooth.
Many thanks for swift response. 
I know this thread is a little old, but I got some additional before and after data for this.
Just did this mod today.
Tests was on an nodemcu ESP8266.
I used a IP55 box with a screw on lid.
nodemcu was in my garage with door closed about 10 meters or so away with 2 double later brick walls in-between.
open box (onboard antenna)
Wifi strength -70dBm
RSSI 60%
closed box (onboard antenna)
Wifi strength -71dBm
RSSI 54%
closed box with mounted external antenna
Wifi strength -60dBm
RSSI 80+%
So I guess this really works. I used an antenna salvaged from an old ADSL router.
Hi, I installed an external antenna to a Nodemcu esp32. It made it worse. Before this antenna, I had about -56dBm. After I installed an external antenna, I have about -62dBm.
The yellow line shows before and after:
That is an excellent signal strength. You had no need to do the mod.
You have done something incorrectly. Maybe reversed the centre and shield? Shorted? Forgot to cut the traces to the PCB antenna?
No, you don’t. You remove the zero-ohm resistor and bridge a blob of solder to the antenna connector. A solder bridge is still zero ohms.
The signal strength was good because I worked with this device in a different location for testing.
I double checked, and everything is set up correctly. I am not sure what else could be done, but because I damaged the NodeMCU, I have no choice but to use it. It replaced my old device.
Can you post a close up photo of the modification?
Has anyone done the antenna adaptation on an esp8266 v3? I’m looking for a female sma with a 3dbi antenna
Anyone able to provide photos of the antenna mod, i would like to add the IPEX U.FL SMD connector
I managed to tear off the uFL connector and 0ohm off my Heltec Lora V2 and was able to replace it with side mount sma. Didn’t take the chance of scraping off some of the back to secure the mount to the board so used hot glue. I was a bit surprised it worked as solder was so fine.
the ufl connector of the heltec wifi lora is for exclusive lora use.
the wifi antenna is on the bottom on the board
Using one of these 8-relay ESP8266 boards for outdoor lighting. For some unknown reason, it worked fine for months, and recently began losing wifi connections frequently. Decided to add an external rubber-duck antenna to the outside of the plastic box containing the board and wiring. On the attached ESP-12F board, the ground is on the outside left antenna trace, and the signal source is on the next/adjacent trace.
Signal on the stock board currently running is down in the weeds 
