I have succeed on two ESP32 modules to talk to each other apart from about 100 m with "Long Range Mode" with ESP-NOW protocol.

It didn't come easy.   It has started with only 10m range performance with two ESP8266 boards.

Eventually it ended up to 100m one step at a time by adding external antenna and change the mode to "Long Range Mode".

I had to abandoned ESP8266 since the "Long Range Mode" is only available on ESP32.

Also, the external antenna really boosted the range.

At my house from outer wall to surrounding, I got about 100 m.

However, I found out that signal spreads out much further when I tried on a less dense commercial parking zone.

 

I have used two LILYGO TTGO T-7 V.1.3 mini ESP32 boards for this.

Also, I have attached external antenna on it.

Key : Make sure both end devices' antenna must be outside to get maximum range.   

         If one of the device is inside a contained area such as a house or a car, signal range drops by more than a half.

 

Attachment of External Antenna : There is a trick to attaching it.   Every antenna has center cable shielded by metal thread.

Just consider that metal thread as (-), and center core cable as (+).   

Now, solder them on the on-board antenna after cutting part of it.(refer photo)

After soldering, make sure cover it up with hot glue gun to make it secured, otherwise, it will break apart easily.

This is my quick dirty trick.

(* I am not a microwave engineer.   So, if you know a better way, just follow your way.   Mine is from online without any proof. *)

 

 

These are my two devices powered by power banks.