What the article didn't mention is the possibility to build a "wired wireless" network using leaky feeder [0]. Unlike a normal coax feedline, a leaky feeder is a special coax feedline that is designed to leak a bit of RF along its way, thus providing wireless coverage on everywhere the coax runs. It's useful in areas when using antennas at fixed points is difficult to provide a throughout coverage, such as a building complex or a tunnel.
They mention that bandwidth is anemic at higher frequencies... so how well does this really work? And what kind of power is being pumped through those lines?
LTE is 700 to 2600 MHz, depending on the band. Wi-Fi is 2.45 (or 5 or 60) GHz. They’re all considered microwave and face similar signal integrity concerns in the same channels.
The prefix micro- in microwave is not meant to suggest a wavelength in the micrometer range. Rather, it indicates that microwaves are "small" (having shorter wavelengths), compared to the radio waves used prior to microwave technology.
Microwaves are a form of electromagnetic radiation with wavelengths ranging from about one meter to one millimeter; with frequencies between 300 MHz (1 m) and 300 GHz (1 mm).
Those are pretty clever too. I don't think I've seen one in practice (although I may have inadvertently made one with bad SMA grounding efforts :-))
I picked up a vector signal generator which has as one of its standard waveforms 802.11 (b/g/n variants) I use its output on a bit of coax to the SDR sitting on my bench while working on the WiFi tranceiver code. I have referred to that wireless over coax (it does bluetooth, zigbee etc so those work over coax too :-)).
Back in Blekko's first building space the office was on the other side of the building from the nearest cell tower so we installed one of those cell "repeaters" which was essentially an antenna in the suite connected via a bidirectional amplifier to an antenna on the roof that was pointed at the cell tower. The FCC later outlawed them but I always wish that I had kept it for those situations where cell service was hard to get.
It suffered from the fact that the antenna was not omni-directional so you really wanted it on one side of the space so that everyone in the space would be able to hit it with their phone. It was an improvement though over the AT&T wifi connected "mini cell" because it carried everyone's signal, not just the AT&T ones.
I recently installed an access point in an elevator. All that we did was put a cat6 into the umbilical cord that contains the elevator power, controls, etc.
[0] https://en.wikipedia.org/wiki/Leaky_feeder