Investigating an “evil” RJ45 dongle

RJ45 nazi here: these should be called 8P8C

I’ll show myself out

I don't mind calling the connector an RJ45, but calling this thing an "RJ45 dongle" makes my eye twitch. It's an Ethernet dongle - RJ45 can be used for a lot of other things. For example I've seen "RJ45 dongles" that convert USB to RS232 serial for the console ports on a lot of networking equipment.

At least they didn’t call it a wired WiFi dongle.

I did wired WiFi for CES one year. Made having our iot devices on WiFi on the floor much better than other vendors. It’s a long boring story but it was a fun hack.

I’m actually really interested: I have a piece of stage lighting, that has a 2.4 GHz Wi-Fi controller. I’d love to convert this to wired Wi-Fi. Can you share what is necessary to achieve this hack? Can I “just” run antenna cable between router and controller? Or what kind of radio physics needs to be understood?

Truly wired WiFi is easy with the devices that have threaded SMA connectors for antennas, e.g. the motherboards or the mini-PCs that allow the use of external antennas.

With those you just need coaxial cables of appropriate lengths, also with SMA connectors, for making point-to-point connections.

If you want a network where each device can talk with any other devices, you also need a splitter, also with SMA connectors.

Many WiFi M.2 2230 cards have MMCX coaxial connectors on them, which allow the connection of internal antennas attached somewhere on the case of the laptop or mini-PC.

For these, there are MMCX to SMA adapters, which you can use together with SMA cables.

Some M.2 cards have even smaller U.FL coaxial connectors. For these there are U.FL to SMA adapters.

For devices that do not have any standard antenna connectors, one may need to modify them, to solder some RF connectors, which is hard to do without greatly lowering the quality of the WiFi links, due to additional attenuation and reflections.