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by tomxor 549 days ago
Is the gain in bandwidth for your wifi really worth the reallocation?

This change opens up 1200 MHz of bandwidth between 5.925 and 7.125 GHz.

> quite a lot of spectrum real estate

Amateur radio is scattered all over the place, but excluding radio satellite they are mostly bellow 300 MHz... ignoring the fact that they are tiny slices, the upper limit of bandwidth you can hope to gain under that frequency is 300 MHz (for all of it), and considering that most of that is not amateur radio, you are going to be gaining a negligible amount of bandwidth that cannot be practically used for a single application because it is not contiguous.

The higher the frequency the more bandwidth is available. For high throughput applications reclaiming these relatively low frequency bands is not useful.

2 comments

> but excluding radio satellite they are mostly bellow 300 MHz...

The 70cm band (420-450MHz US) is heavily used. I'm sure cellular services would love it. On the other hand, it is a secondary allocation with other users (e.g. military radars) having priority.

The 23cm band is another secondary allocation, from 1240MHz to 1300MHz-- wide enough for 3 wifi channels. On the other hand, you'd have to kick out the radiolocation service, and it's not contiguous with a big block of channels to make it worthwhile.

Then above that amateur shares frequencies with some of wifi and then microwave frequencies that are so high that they are undesirable.

The 70cm band is just 30 MHz wide in the US. The point was that none of these other allocations are wide enough to be useful for things like WiFi, which is currently using up to 320 MHz channels and needing several of those channels to avoid clashing with other nearby networks.
23cm is under fire in Europe to protect GNSS services from potential interference. Allowing unlicenced operation there is very unlikely to ever happen.
> 1240MHz to 1300MHz-- wide enough for 3 wifi channels

Wifi isn't necessarily a minimum of 20MHz. Wifi HaLow goes as low as 1 MHz.

As in, something that happens to be called Wifi but is IOT focused and doesn't interoperate with normal consumer devices. It's not a wealth of spectrum in any case, and the fact that a lot of the radiolocation services are satellite based ... they're not going anywhere.
Lower frequency means longer wavelength and longer wavelength penetrates structures better. Or is that over simplified? I’d think the goal of reclaiming some of the lower frequency spectrum is not to try and solve bandwidth issues but to augment consumer wifi with more connectivity options for devices and applications where connection reliability is more important than max throughput.
longer wavelength also means longer antenna, which doesn't fit most use case for inside usage.
Have you seen modern cell and wifi antennas? The wavelength of wifi is 11cm so you make a quarter wave antenna and print it right on to the board [1].

1. https://www.antenna-theory.com/antennas/patches/pifa.php

"below 300MHz" means a wavelength of at least a meter.