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Post by havelock on Sept 7, 2010 11:16:53 GMT 1
I believe that a company (Avanti?) is soon to be launching a satellite with the aim of increasing the availability of wifi.
I can understand that a satellite could be used for downloads but how would each individual PC, mobile, etc communicate with the satellite to tell it what to download and how would uploads happen without each peson having a transmitter?
I believe that, currently, satellite TV requires a landline for folks to interact with e.g. on-screen voting and that all programme content is broadcast at once so that one just selects which programmes to watch as opposed to which to download.
Anyone know any more about the satellite communications business?
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Post by pumblechook on Sept 7, 2010 11:27:38 GMT 1
I can't seem to find anything on this. I would have thought that any two way satellite link would be limited to a few users due to lack of frequency space.
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Post by havelock on Sept 7, 2010 11:30:07 GMT 1
Quite - that's why I can't figure out how a satellite can improve access to wifi. Their home page says "Welcome to Avanti Communications the satellite broadband operator" But doesn't explain how the two way communication of internet (compared to broadcast TV) is supposed to work. www.avantiplc.com/broadband/satellite-broadband/index.php
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Post by lazarus on Sept 7, 2010 11:36:46 GMT 1
I think you will need some sort of land or mobile line as well.
I remember that some company way trailing this back in the days before broad band was widely available. Since usually most of the data came to you and only a little went the other way, a land line was used for requests but the information was broadcast by the satellite. I can't remember the company doing this and I don't think it ever took of. Perhaps this is a similar idea but I can't see how it could match current broad band or the new 4G.
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Post by pumblechook on Sept 7, 2010 11:42:52 GMT 1
Looks like it is just a gap filling exercise. I did know someone in rural N Yorks a few years ago who had satellite Internet before broadband was generally available. It will be expensive and limited. Whatever band width is made available will be multiplied by 8 as there will be 8 beams directed at different areas of Europe but the number of possible subscribers I would have thought would be very limited. news.bbc.co.uk/1/hi/technology/8090895.stm
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Post by pumblechook on Sept 7, 2010 11:47:35 GMT 1
That must be it as with my friend in N Yorks; the uplink is via a phone line. Even so there will be a low limit for the number of subscribers. The satellite sends subscribers the web pages they request. Too many requests will slow the download speed.
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Post by havelock on Sept 7, 2010 11:48:53 GMT 1
That's why I couldn't see how this was going to hugely increase the number of people with broadband access in rural areas.
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Post by pumblechook on Sept 7, 2010 12:02:27 GMT 1
Bit technical.... By using higher frequencies (Ka band) than are used for sat TV greater bandwidth is available and more directional dishes can be used, meaning separate beams directed at different parts of Europe so that frequencies can be re-used. You can get a doubling by using a mixture of horizontal and vertical polarisation (or left.right hand circular) as in Sat TV. I have seen a figure of 50,000 customer terminals which is next to nowt wrt the population of Europe. www.hnseu.com/files/press/27-04-10%20Hughes%20and%20Avanti%20Expand%20Ka-Band%20Satellite%20Services%20Footprint.pdf
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Post by havelock on Sept 7, 2010 12:04:57 GMT 1
Yup but it still doesn't solve the two-way part of the problem
(or does it and I've missed that bit - if so, please try again :-))
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Post by pumblechook on Sept 7, 2010 12:09:11 GMT 1
It is either a land line for the uplink or a low bandwidth satellite uplink. It is usual for most broadband systems for the uplink to be must slower than the downlink.
Will need to do some more reading up.
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Post by pumblechook on Sept 7, 2010 12:14:22 GMT 1
I am not sure a customer satellite uplink is actually very practical. It might need to be relatively high power and may not be allowed. There is a fear also that in the wrong hands it may be used as a jammer.
(I have messed around with Sat TV for years and was a BBC transmission engineer some years ago)
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Post by kiteman on Sept 7, 2010 22:12:34 GMT 1
Existing satellite internet systems send via satellite, but upload via phone line.
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Post by pumblechook on Sept 7, 2010 23:09:54 GMT 1
If you look at a satellite uplink station they do appear to have larger dishes and higher power transmitters than you would think is necessary. I think it is anti jamming measure. A pal of mine said he was going to try and jam a broadcast satellite. I don't think so mate; it would cost a few hundred grand.
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Post by Mr Red on Nov 1, 2010 11:29:43 GMT 1
Doesn't Sky do this?
download = downlink
upload = broadband (or dial-up as was)
Downloads therefore are quick. but the sharing ration must be 10,000 : 1 or maybe 100,000 : 1
Burst speeds are fast.
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Post by hrahsteddy on Aug 28, 2013 7:50:19 GMT 1
As we know for different people they use different kinds of mobile phone signals. Just as the people around you like your friends, your colleagues, your family members and so on, they may use the different mobile phone signals as now there are various mobile phone signals from different companies and of which the frequency bands are also different such as the CDMA, GSM, DCS, PCS, 3G, 4G LTE and 4G Wimax. So in different conditions and circumstances people are in need of the mobile phone jammers that of different frequency bands. But if people are in great need of a mobile phone jammer via which they can decide the jamming frequency bands what kind of device should they choose? Of course, the adjustable cell phone jammer is the best for them in such condition.
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