Extending WiFi and Bluetooth Range via an External Antenna

WEMOS devices are a series of very popular and very reliable ESP devices with many cheap clones available and with varied combinations of features for various purposes. Most of the time it seems very useful to extend the "wireless" (both WiFi and Bluetooth) range of these devices, especially because they are so useful that the small trace antenna does not do them justice.

The image shows in red the snipping points on the PCB that have to be made in order to split the antenna connector into ground and signal. To perform this modification, either use a scalpel or a Dremel to very gently cut through the copper trace on the PCB - typically, the PCB does not contain any other circuitry in the upper blue lamelle which is reserved for the trace antenna, such that it is more or less alright to just cut the PCB, however, that is not needed and the traces can be disconnected on the red lines without having to snip all the way through the PCB material.

After cutting on the red lines, the two traces in the image to the left are the traces that an antenna can be connected to. Even though the image provides a guide which is ground and which is the signal, it is easy to determine which is which by simply using a connectivity tester and then checking connectivity between either of the two traces and, say, the exposed metal of the USB socket, which will be the ground trace such that the other trace will be the signal trace.

The trick applies to ESP8266 or ESP32 development kit boards all the same.