JB,
Many thanks for the link - interesting reading.
The Power Line Transmission (PLT) systems could pale into insignificance when measured against WLL.
In spite of the drawbacks PLT does have one major advantage. Accessability. As most of the UK has mains electricity supplied the greater majority of people will have access to an internet service. This is a stated aim of this government.
The WLL system as being rolled out by Soma , in the USA, will require transmitter sites - no problems there - and hardwiring or SUHF data linking to a core facility. Again no problems. And the need to generate profit.
Due to the frequencies in use, 1.8GHz upwards, from a safety aspect this would appear to be the better system with no more interference to aircraft systems than at present.
Users of harmonically related frequency bands may not be so impressed but at these frequencies it is easy to use stripline filtering etc and reduce spurious emmisions to a very low level but I would like to know the units effective radiated power both from the main transmitter sites and the local terminal.
I would like to try one and would, at this time with the limited info available, prefer the WLL to the PLT system. Only time and testing will indicate which one is the better system overall.
One thing the WLL system would need is a good encryption system to prevent unauthorised access to data. It is a pity that a lot of firms currently using a wireless network pay little attention to this.