This neat little 2.4ghz OLED display spectrum analyzer could help you diagnose wifi & RC transmitter problems, Google search for "Lantian Mini High Sensitive 2.4G Frequency Spectrograph" to get one, but they're just bare-board devices, so I carefully measured mine and made this perfect little robust case for it.
You'll need four m2x6 screws to attach the case, by first removing the top right & bottom left screws from the front & back of the module, then screw in the two halves of the case to the module using the m2x6's.
I printed mine in PETG on a Prusa i3 Mk3 with no supports or rafts, at 0.10mm layer height to maintain detail on this small object, it took 1H 15M to print both. Printing it in PLA should also be good.
I have included two .stl sets of the shell, one set with rounded external edges to print, and one set with square edges to make it easier to remix.
--- UPDATE ---
I have added a new shell with an RP-SMA socket for an external antenna.
It works very well once modded, turning it into a much more useful device, please see this thread on RCGroups for how I added the socket to the board: https://www.rcgroups.com/forums/showthread.php?3120831-Miniature-cheap-Lantian-2-4ghz-band-scanner