All posts by Nicholas Willmott
Below are all of Nicholas Willmott's postings, with the most recent are at the bottom of the page.
Thank you for your explanation Andrew Brown and jb38. Worryingly the Bath relay (although group A and not itself affected), still has to pick up the signals for D3&4 on C54 and HD on C58 from Mendip to relay them to Bath on C28 and C22 respectively. So could 4G interference prevent the Bath relay picking them up from Mendip to rebroadcast them? What kind of filters will they need to use at the Bath relay to get around the problem?
The question remains, do they really need to use the ex-TV UHF channels 61-69 for 4G?
Why not replace the rest of the 1710-1880 MHz 2G, and all the 880-960MHz 2G with 4G? Surely 2G is obsolete now.
Why not just switch off the 1900-2170 MHz 3G in a stroke and replace it with 4G?
Why not switch off the MW radio band (540-1600 kHz) and replace it with 4G? I don't really see the need for MW radio any more, surely hardly anyone listens to it these days.
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Briantist: Mendip alone has 61 relays. Only two are fibre optic fed from Mendip, the rest are over-the-air fed for rebroadcasting to their local areas. Other group C/D transmitters such as Winter Hill have relays which are over-the-air fed. So altogether, won't there be an awful lot of relays to worry about, anything but a small number? Any idea how many relays in total might need some sort of protection from 4G interference.
Why would MW not provide any useful bitrate for LTE? Please explain the problem more fully.
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Thanks Briantist. So basically 4G LTE uses channels 5 MHz wide (thus collectively they won't directly map to the traditional UHF TV channels 61 to 69 which I've been led to believe are 8 MHz wide each).
Now that DAB is increasing in popularity, could they turn of FM radio (88 to 108 MHz) and use that for 4G LTE - would the resulting clear 20 MHz bandwidth be enough?
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It's all very well wanting to use the former TV UHF channels 61-69 for future 4G LTE. To get decent analogue / digital TV reception of C61-69, you needed a decent aerial, ideally group C/D. So does this mean you'll need a group C/D aerial for a 4G mobile phone? Even the smallest C/D aerial (10 elements) intended for a storng singnal area is quite big; way too big and impractical for people to carry around for use with their mobile phone / smartphone.
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Thanks Briantist. It amazes me that a tiny internal aerial will work for a mobile phone in the 791-862 MHz range, yet that same frequency range (C61 to C69) required such large group C/D aerials (ideally rooftop mounted) for decent TV reception. How is it possible to for such a minute aerial as used in a mobile phone work for a 4G LTE mobile phones, yet not for TV. It's the same frequency range at the end of the day.
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Further to my last post, I've looked at the complex frequency chart mentioned at the top of this page. I see that the range 275.0GHz to 300GHz is labelled Not Allocated. If that range is not allocated (vacant), why don't they use that range for 4G LTE, and not bother using the former UHF channels 60 to 69?
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Wouldn't the Bath relay still need some sort of adjustment to allow for PSB1 moving from UHF 61 to UHF 49? From what I understand of the way it works, until now it must have picked up PSB1 from Mendip on UHF 61 for rebroadcasting to Bath on UHF 25. If nothing is done, surely it'll now just relay a blank signal on UHF 25. Therefore, wouldn't the engineers need to adjust the Bath relay to rebroadcast UHF 49 instead of 61 on UHF 25?
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Over the course of time, a number of users have posted comments about ITV+1 and C4+1 on D3&4. We've already had the reason/excuse for that, i.e. being timeshifts of regional channels they have to be on D3&4. Here's a simple workaround to that - don't bother with regional variants of ITV1+1 and C4+1, in order that they can go on SDN. Put ITV+1 Wales on SDN in Wales, and ITV+1 London on SDN throughout the rest of the UK. Put C4+1 London ads on SDN UK-wide. The freed capacity on D3&4 could then be used for ITV3 (in place of ITV+1) and ITV4 or Film 4 (in place of C4+1).
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Dave Lindsay: My suggestion was to fit in with the fact that there are currently only two versions of SDN, 1) SDN Wales, 2) SDN Not Wales.
Would it be technically possible/feasible to make four versions of SDN as follows: SDN Wales, SDN England, SDN Scotland, SDN Northern Ireland? Then you could have ITV+1 Wales on SDN Wales, ITV+1 London on SDN England, STV+1 on SDN Scotland and UTV+1 on SDN Northern Ireland.
With so little regional variation on ITV these days (I think the regional news bulletins are the only differences) do people really need regional variations of ITV+1 (at least in England anyway)? If you want to watch the correct regional news, e.g. Calendar, Granada, Central, Anglia, Meridian etc, watch it at the proper time on ITV C3. If you can't be bothered to watch it the proper time you'll have to make do on London regional news if you live in Yorkshire, the south coast, south west, Midlands, etc. Wherever you are outside Wales, most of the rest of ITV+1 (Coronation St, Emmerdale, Dancing On Ice etc) would be the same on ITV+1 would be the same on ITV+1 London one hour late as on your correct regional ITV at the proper time.
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Saturday 2 March 2013 10:42PM
I said this on the other 4G thread, but Briantist redirected me here.
Even if a 4G signal in the channel 61-68 range, and the TV transmitter you pick up from uses channels 52-60, surely 4G signals will be a totally different format to Freeview (DVB 8K) signals. In which case, wouldn't Freeview TVs and boxes automatically distinguish 4G signals from Freeview signals (and simply ignore 4G signals) by the difference in format? If not, please explain.