< kind of military system would have either spilled over
into the 5Mhz band or didn't have enough receive filtering itself.>
How about a little hint here? Where is it used? Some one of a kind test bed? Was it COTS(Commercial off-the shelf ) or something built under a Government Contract? If a Gov Contract, there would be lots of Mil Specs listed in the contract and RF tests far in excess of anything the FCC requires. When the equipment left the plant, it would be working to the contract spec, however, there could hardware failures in the field that could be undetected by the users, or ( quite likely) intentional mis-ajustments. I do not believe they much care about the FCC regulations.
The Military goes by somewhat different rules. I have never seen a spread spectrum military system, but the big talking points on SS are that the transmissions are hard to spot using the equipment for monitoring enemy transmissions. The SS would show as a small bit of interference and by using frequency hopping it would be randomly spread around. There did not seem to be any concern about causing interference to other users, in fact during time of stress, there would stand off jammers pumping lots of RF into some selected area.
By the way, years ago there was something called a Spark Gap Transmitter. I have never seen a spectrum plot but expect it was rather dirty. Perhaps you could complain about that as well as some old CDMA systems that are no longer in use or some military system that was not designed to be compatible with civilian life. I have heard some rather vague rumors of CDMA systems working in some places (Korea and US come to mind) but very few of WCDMA systems working.
What does this mean?
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The traffic in big cities such as Shenzhen and Shanghai has reached about 40,000 users per square kilometre, according to Wang Xiaoyun, manager of the Technology Development Division under China Mobile.
New frequencies and new technologies are needed to satisfy users' demands, she said.
The frequencies are also not sufficient to meet the demand for business growth. The existing frequencies used by China Mobile at present can only provide a capacity of 50,000 users per square kilometre after advanced technologies were adopted, such as frequency hopping and multi-level frequency multiplexing, according to Wang.
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Message 16057516
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