[RonM9] wasn’t happy with his 50 foot range on his NRF24L01 project. The RF had to cut through four walls, but with the stock modules, the signal was petering out after two or three walls. A reasonably simple external dipole antenna managed to increase the range enough to do the job.
[RonM9’s] instructions show where to cut away the existing PCB antenna and empirically tune the 24 gauge wire for best performance. He even includes an Arduino-based test rig so you can perform your own testing if you want.
There’s no doubt an external antenna will make a great improvement on a wireless system. We wondered, though, how much benefit could have been gained from adding a counterpoise that was longer than a quarter wave (which, at that frequency, isn’t all that long). Ham radio operators often use counterpoises to improve compromised antennas. On the other hand, dipoles are slightly directional, so that’s an advantage too. [Ron] points out you’ll get the best performance if you mod both the transmitter and receiver and line up the antennas.
We’ve seen people just tack a wire on the antenna (see the video below), but this hack struck us a bit more technically sound. If you want to learn more about the NRF24L01, we’ve covered it before.