Mike, the power on the birds is crucial. The number of calls they can handle depends on the amount of electronic gizzards, [when the circuits are full, they can't do more] and the power supply. They have batteries because they go round the earth and experience night-time every half hour or so at their darkest time, which is when the orbit is edge on to the sun. At their lightest time they have almost no night time. Sometimes many customers make calls, other times few are calling, so the satellites need somewhere to store the power collected from the photovoltaic cells which make electricity from the sun shining on them - sort of like leaves make a plant's fuel from the sun shining on them.
Now if you could put very big photovoltaic panels and hefty great batteries in space, you could just have a big surplus of electricity, not worry about it and heaps of power would always be available. No need for Readware's decibels. But the nature of satellites is that they need to be cost-effective. Junk in space costs big dollars. So surplus batteries or photovoltaic panels wastes big money.
So there are compromises. According to Readware, but not Mr Adrenaline, but according to another Globalstar designer I know [from the Qualcomm side], there is a shortage. But also according to Mr Readware, there is not a shortage.
No electricity means no calls. So they have to manage demand and having variable power output thanks to the cmdaOne system being used, the satellites can eke out their power supply and maximize the amount of calling. Which is where the money comes from. Which we want lots of as that represents customer contentment and many happy calls.
We are not talking about the bird's life here. That is set at around 7 years give or take a bit. We are talking about the power available over periods of a few hours.
My concern is that the power is not going to be sold effectively, which means to the highest bidder. It is going to be managed on a "no service available" basis. That will not please people calling home from the Titanic. Flat battery = "NO SERVICE AVAILABLE". Which need not be the case. By correct pricing, this need never happen. By limiting the number of subscribers this won't happen either, but that means fewer people get to make calls and shareholders get less money. Which is not what many of them want.
You see the problem I have with it?
It seems pretty straightforward to me.
On latency, the only way to speed up the signal is to increase the gravitational field in the vicinity. Trouble is that will increase our need for speed too, at an ever increasing rate until we disappear into our own black hole. Sorry, no gadget for handsets to avoid the propagation delay from the handset to the satellite, back down and around the fibre. Until they change physics, relativity and all that. Which isn't happening any time soon. Delay in the electronic gizzards can be sped up with smaller and faster circuits. But that can't help the geostationary problem of distance.
If the ITU thinks 400 milliseconds = nearly half a second, is okay for toll quality, they have got another think coming. They have got away with that due to lack of competition and tolerance for poor quality. But competition is increasing and quality will be demanded. That means 100 or at most 200 ms delay.
These are hydropower/natural gas powered rants! Like many news reports, the actual shortage of electricity in Auckland has been exaggerated. It affects only the central business district and even there they have some supplies though on an intermittent basis. Auckland is unaffected as far as I can tell - there are quite a few generators hanging around the footpaths making a racket though.
Maurice
PS: With Globalstar, the voice delay will vary somewhat because when the satellite is directly overhead, it is 1400 km away. When it is nearer the horizon, it is much further away. About 2000 km. Iridium is closer, so less voice delay from the propagation time. |
