Comment by adrian_b
13 hours ago
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.
I would imagine that the stage lightning microcontroller is running a variant of ESP8266 or something similar where the "antenna" are actually thick traces on a circuit board (https://www.electronicwings.com/storage/PlatformSection/Topi...). This is obviously good enough for regular WiFi, but I would imagine this would complicate an attempt for wired WiFi tenfold.
If you build this and expand this to a blog post with some photos and some demo, you can post it here and I guess it will get a lot of upvotes.
Unfortunately, I no longer have the opportunity to do this.
Some years ago, I have been working in designing certain kinds of WiFi devices.
For their testing in a laboratory, a wired setup was used, exactly as described, i.e. with SMA coaxial cables replacing the antennas in the units under test, together with splitters and/or directional couplers to implement multi-point networks, and together with attenuators to simulate a greater distance between the units under test.
The majority of the tests concerning hardware and software were done using the wired setup, which allowed the simultaneous testing of a great number of units in a small space, without interference between their different tests. Only a much smaller number of tests was done with antennas, on the units that had already passed all hardware and software tests, so only the behavior of the antennas remained to be checked.
Such tests in wired setups were done both for the production units, for quality control, and for prototypes, where new versions of hardware and/or software were developed, and it made no sense to waste time with wireless testing until the new hardware and/or software was proven to be completely functional in the wired setup.
In a testing laboratory, there would be a huge amount of coaxial cables and adapters, attenuators, splitters and directional couplers, and of WiFi interfaces, so demonstrating a complex setup would be easy. Otherwise, collecting enough devices and accessories to make an impressive demonstration would be costly when you do not actually have a need for those devices.
In a home where you have an Internet router/gateway that has external WiFi antennas and you have a desktop using one of the many motherboards that include a WiFi interface with connectors for external antennas, you could use an SMA coaxial cable between your desktop and the router/gateway, instead of using an Ethernet cable.
This would be the simplest example of wired WiFi. There are cases when this would be a good idea, e.g. when the router/gateway has only few Ethernet ports for local devices and those are already occupied by other computers. In this case buying an SMA cable may be preferable to buying an additional Ethernet switch and also preferable to a wireless connection, if your home has many neighbors who also use WiFi, creating a congestion that slows down the wireless communication.