Smart meters and the north-south divide

Normal 2G and 3G frequencies are 900MHz and 2100 MHz, OFCOM are no longer rigid about that "G" must use what bands, but I doubt smart meters are flexible (e.g. to use 2G at 1800 MHz)

O2 are switching off 3G next year.

Ah, so the "radio waves" technology (to use their term!) is not a dramatically different frequency to mobile phone frequencies. So propagation and aerial design will be fairly similar. From the article, I'd thought it might be orders of magnitude (1/10, 1/100, 1/1000 times) lower than mobile frequency. Would the 412 MHz as opposed to 900-2100 MHz really be

I imagine the benefit is not different propagation characteristics but that there is an established network of mobile phone masts which gives fairly good national coverage, whereas receivers for 412 MHz may not be as comprehensive coverage.

I wasn't sure whether the 2G/3G/4G/5G difference was ranges of frequency or whether it was different modulation. In the same way as HD television *can* be encoded as MPEG1 (as used for SD) rather than using H264 and *can* be modulated as T1 rather than T2 - it's just that it's never (*) done.

(*) AFAIK

As someone waiting for his 5th meter in 3 years I can’t wait for a better comms system in Scotland.

I’ve been in touch with Octopus about alternatives and it seems they now do have a system for moving selected customers to cellular data but, as ever, it involves them having to work through a script of steps to be taken first which includes Octopus and the DCC investigating local reception. Only after every step has been taken is there a chance of getting a “cellular meter”.

I really don’t understand the necessity for the sharp divide between network options. Electricity companies should be allowed to fit whichever comms unit works best.

Tim

yes, and more importantly, the lower frequency has a better chance of penetrating the walls of the house.

Really?

Why would that be?

That BBC article explains that the comms are all outsourced to Capita. Enough said. I've had enough experience of various branches of that company to not expect that anything they do to work properly, or at all.

To almost quote Goering, "whenever I hear the word 'outsource' I reach for my pistol" ;-) (Though

Smart DCC is licensed by the govt to run the service, (until Sept 2025 which can be extended by 1-6 years) but they use Capita to operate the business, who in turn outsource the actual comms to O2/Telefonica for

Coincidentally (or not) the web form for submitting enquiries to Capita isn’t working.

Tim

Yes, I can see that a wavelength of 15 cm (2 GHz) might get through apertures in metal window frames and between rebars in concrete, in situations where 75 cm (400 MHz) might be attenuated more. Or conversely, 15 cm might be diffracted more (spreading the signal more "thinly") that 75 cm. I know that 5 GHz wifi has a shorter range than 2.4 GHz for (I presume) the same transmitter power at the router and at the laptop, suggesting that it is attenuated more by walls and windows.

How much difference does it make to line-of-sight and ability to bend around hills etc, comparing 400 and 2000 MHz?

How widespread are the 400 MHz receiving masts, compared with mobile phone masts?

Don't think I've seen a list of sites published, you'd have to search for planning applications by Arqiva, e.g

Given that Kettering isn't "north", that must only be used for water meters, not gas/elec.

There is another factor

There is another factor. A higher frequency antenna has a smaller "capture area" than a lower frequency one of equivalent directivity and proportional bandwidth. For example, if one takes a half-wave dipole as a reasonable approximation to what is used in WiFi access points and smart meters a 400MHz dipole will be twice as long as an 800MHz dipole. If both are placed in the same rf field strength at the appropriate frequency for each the larger antenna will receive four times more power than the smaller one.

If there isn't enough space for a half-wave dipole (including the empty space around it that it needs to work optimally) then the compromises begin. Smaller size than a half-wave dipole at a particular wavelength means either less bandwidth or less gain.

John

The northern system is run by Arqiva there the ones that do most all radio and TV transmission.

The great idea was that to the greater extent lower frequencies can travel that bit further but where there high and or hilly ground around the results will be shielding and remember the signal has to penetrate the house or building then they, the gas or smart meter has to generate the radio signal to be picked up by that network.

The real issue is that there are an insufficient number of base stations where as with a cellular network frequencies can be reused close together and there are a lot more base station sites!.

They would in effect have to build a cellphone network that will cost a bloody lot of money, better to use existing ones.

I don't know who had the clever idea of that system, wasn't an engineer maybe Arqiva wanted to make a few quid and thats was a way to do it?..

Reflection works better at cell frequencies but the real problem is the meter has to generate sufficient output to go further as there are a much lower number of base station receivers they haven't the density of what a cellphone network can do..

Yes indeed!..

I wonder if older northern houses being made out of thick stone while southern ones mostly made out of brick might have anything to do with it too?

Mobile operators could just run 4G/5G at 400MHz if they wanted, on existing sites with possibly a few frontend changes?

Apparently part of Arqiva used to be National Grid Wireless, although I'm not sure what NGW did aside from broadcast stuff? (NGW absorbed Crown Castle which used to be BBC Transmission, but I'm not clear what NGW did before the merger?)

Theo

Shouldn't have thought so..

Doubt if they'd do that cost more then they'd like to pay I'd bet!..

BBC transmission and NGW and NTL all ended up as Arqiva!...

Isn't that what Dolphin tried to do with TETRA?

Never mind stone walls affecting the signal to the nearest mast. We had problems with comms even between the gas meter and the electricity meter.

Our gas meter is in a different location in the house to the electricity meter, and the direct route passes through two exterior stone walls and an interior brick (not wood and plasterboard) wall (*). When Octopus first installed smart meters, everything worked perfectly. But a few months later we started to get very intermittent gas results reported on the In Home Device and set to Octopus's app. I'm not sure what may have changed. What frequency is typically used for meter-to-meter comms?

Octopus came out very quickly and fitted a new gas meter which had newer technology. Unfortunately the fitter didn't know what was different - whether it was a stronger signal or a different frequency - but he said that the first chap must have been using up old stock.

(*) That part of the house dates back to the 1800s.

zigbee at 2.4 GHz, or 868 MHz