Three Quick Tips About Using U.FL
Liquid Soulder 
Protect
You can kind of think of the outside gripping portion of the female U.FL connector as being made out of dragonfly wings - very pretty to look at but also fragile. Putting unnecessary forces on them, for example a torque from pulling the cable in a funky way, could cause them to bend away from the male side of the connector and no longer make a reliable connection. Keeping this from happening should also be a priority when moving a project or creating a final installation.
Preventing this weird torque is called strain relief and there are a couple ways to do it:
- Tape down the cable
- Put the cable through a strain-relief hole on the board (if applicable)
- Glue down the cable
- Or think of something else as long as it relieves any forces that might be accidentally applied to the cable
With any of the strain relief methods you should allow the cable to bend naturally to the securing location so as not to transmit any forces or torques to the connector. The ESP32 Gateway has a really convenient channel right below the ESP32 module that you can use to make a tape tent. This keeps the connection nice and secure without having to press down on the cable at all!
If there is a through hole nearby that is not being used and wide enough, you can also thread the u.FL connector before connecting. Below is an example of threading the u.FL cable through a mounting hole before being attached to NEO-M9U GPS board. Feel free to add additional strain relief using hot glue or tape against the board to reduce the amount of forces on the small connector.
