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I don't get it. What difference does it make if US delays roll out when many other countries are going ahead already? It's not like Boeing and Airbus planes don
by AlexandrB 5y ago
I don't get it. What difference does it make if US delays roll out when many other countries are going ahead already? It's not like Boeing and Airbus planes don't operate in China, for example.
- PicassoCTs 5y agoIts not the same 5G in the us. Its the 5 grapefruit wavelength standard. If you measure them differently, different standards may apply.
- firebaze 5y agoWe're talking of different bands. Like visible light vs. infrared or x-ray.
- onphonenow 5y agoActually, other countries (like france) did their own tests and threw out the crap from AVSI/RTCA (who have been very shady about disclosing their data). Japan and other countries do smaller guard bands, some let cell service go within 100Mhz (ie, twice as close). This is really an indictment of the technical incompetence and lack of planning (over 10 years) of the FAA.
- p_l 5y agoAFAIK only Japan allows operation anywhere close to 4GHz nationwide, everyone else puts limit at 3.8GHz for nationwide licenses, with occasional location limited <4GHz in UK.
- fomine3 5y ago5G on 700MHz, 1.7, 3.5, 3.7, 4.5, 28GHz are in operation in Japan.
- p_l 5y agoThe page I had seen claiming the licenses for close to 4GHz band were sold might have mentioned it wasn't really deployed so far (unfortunately lost the link :/)
- fomine3 5y agoBands are never "sold" in Japan but assigned to MNO. Those bands are all in operation (some sort of). I found a research from MNO to use 4.9-5.0GHz for 5G near airport: https://www.soumu.go.jp/main_content/000777475.pdf https://www.soumu.go.jp/main_content/000777475.pdf tldr: they need 5MHz guard band and emission adjustment for small cell near 5km from airport / for larger cell near 20km from airport.
- onphonenow 5y agoI was thinking they'd land at something in range of 20Mhz (10% of a full sweep). for guard. That said, the actual sweep is in .1Mhz or less steps isn't it so you should be able to get away with a small guard I think? What is the actual receiver bandwidth?
- tssva 5y ago3500-3600Mhz and 4800-4900Mhz are the closest used frequencies for 5G in China. Much farther away from the frequencies used by the altimeters than the frequencies causing the concern in the US. In Europe the closest frequency being used is 3800Mhz. Again much farther away from the frequencies used by the altimeters.
- AlexandrB 5y agoInteresting. I didn't realize there was such a large difference in the bands used between countries.