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The 600MHz Gamble
6 years ago
General
So 5G is coming to our mobile devices whether we want it or not. And almost all the mobile carriers have staked their claim in the 5GHz band, requiring a transceiver on every other telephone pole or light post or power pole in your neighborhood.
Almost... all.
Because broadcast TV signals have gotten more efficient in the digital age and take up less space, the FCC has mandated the "repack", a de-fragmenting of the broadcast spectrum, getting existing stations moved down into the lower ranges and freeing up space above Channel 35 (roughly 600MHz). And the FCC then auctioned off that bandwidth to the mobile companies. T-Mobile shelled out $8 billion to buy this spectrum with plans to use it for their nationwide 5G coverage. So why is this interesting?
First you need to know about the trade-off between frequency bandwidth and wave propagation. Ultra High Frequency waves can carry a lot of bandwidth but can be easily attenuated by... like... rain. On the other end of the scale, Extremely Low Frequency waves (with wavelengths of thousands of miles) circle the Earth several times before fading out and can penetrate into the ocean to signal submarines... but pretty much all they can do is signal the submarine to rise to the surface where it can use a different radio to find out more. Waves that long are useless for transmitting actual coded information.
5GHz seems like the right choice for something as high-bandwidth as 5G. It only takes a little slice of that spectrum to move a lot of data. But... well... you probably know how hard it is for your 802.11 wireless on 5GHz to get through the walls of your house. Now you've got a transceiver on a lamp post outside trying to get into several houses in the neighborhood. Hence... needing another transceiver every 100 feet to blanket a neighborhood.
But 600MHz... we know 600MHz, it's broadcast TV! The kind you set a transmitter up on a hill and blanket an entire city. It's the kind you can stick up on Mt. Wilson and blanket Los Angeles, Orange, San Bernardino and Riverside counties. If T-Mobile has found a way to push 5G speeds out over the 600MHz spectrum... this could be a huge advantage, especially reaching out into communities outside the major cities.
Is the 600MHz gamble going to pay off? Stay tuned. This is going to be very... very interesting...
Almost... all.
Because broadcast TV signals have gotten more efficient in the digital age and take up less space, the FCC has mandated the "repack", a de-fragmenting of the broadcast spectrum, getting existing stations moved down into the lower ranges and freeing up space above Channel 35 (roughly 600MHz). And the FCC then auctioned off that bandwidth to the mobile companies. T-Mobile shelled out $8 billion to buy this spectrum with plans to use it for their nationwide 5G coverage. So why is this interesting?
First you need to know about the trade-off between frequency bandwidth and wave propagation. Ultra High Frequency waves can carry a lot of bandwidth but can be easily attenuated by... like... rain. On the other end of the scale, Extremely Low Frequency waves (with wavelengths of thousands of miles) circle the Earth several times before fading out and can penetrate into the ocean to signal submarines... but pretty much all they can do is signal the submarine to rise to the surface where it can use a different radio to find out more. Waves that long are useless for transmitting actual coded information.
5GHz seems like the right choice for something as high-bandwidth as 5G. It only takes a little slice of that spectrum to move a lot of data. But... well... you probably know how hard it is for your 802.11 wireless on 5GHz to get through the walls of your house. Now you've got a transceiver on a lamp post outside trying to get into several houses in the neighborhood. Hence... needing another transceiver every 100 feet to blanket a neighborhood.
But 600MHz... we know 600MHz, it's broadcast TV! The kind you set a transmitter up on a hill and blanket an entire city. It's the kind you can stick up on Mt. Wilson and blanket Los Angeles, Orange, San Bernardino and Riverside counties. If T-Mobile has found a way to push 5G speeds out over the 600MHz spectrum... this could be a huge advantage, especially reaching out into communities outside the major cities.
Is the 600MHz gamble going to pay off? Stay tuned. This is going to be very... very interesting...
For historical reasons the full power station changed its virtual channel ID to their new RF channel (apparently back in the 60s or something they were 19, and they are again). But the low power stations, now moved into the 30s, are keeping 19 as a virtual. So, uh... There's now two 19.1s out there. I'm actually surprised that maybe 75% of tuners are handling it.
As for the tuners, it depends on the tuner, I think. I haven't found one yet that would flat-out refuse duplicate channels. Most of them just add the virtual channels to the map (so in the above example, you would get 9.1 KEZI and 9.1 KEZI) but I've met a few Sonys that show the real channel number (9.1 KEZI and 11.1 KEZI).
I wonder... when you ask for 19.1 in your situation... which channel do you actually get?
Now, let's see what happens when I rescan (part of a shuffle was supposed to happen last weekend)...
Nothing. None of them. Hmm. I'lllll... be back later.
I always found that attenuation thing fascinating when I learned about it from my classes. The fact that raindrops can scatter those microwave tower transmissions (because the waves are literally the size of raindrops) is a very interesting issue to overcome.