Tampilkan postingan dengan label Smart meters. Tampilkan semua postingan
Tampilkan postingan dengan label Smart meters. Tampilkan semua postingan

Minggu, 07 Juli 2013

Sunday Smörgåsbord: liberty, the internet, worry, health & Lyle McDonald.

Five items this time, not necessarily related.
From http://en.wikipedia.org/wiki/Smörgåsbord
By liberty, I mean personal liberty. I believe that individuals should be free to do whatever they want, provided that they don't harm another individual. However, collections of individuals should not be free to do whatever they want, as collections of individuals (i.e. businesses) usually try to profit from individuals, so the welfare of the individual isn't of importance. Businesses obviously don't want to instantly kill their customers, as that's obvious and will probably get them sued. However, "killing them softly" isn't obvious!

In the EC, just about everything has a CE kite-mark in order that it may be sold in the EC. Standards include EMC (Electro-Magnetic Compatibility) to ensure that:-
a) Devices don't emit excessive levels of RF "radiation", which may interfere with other devices.
b) Devices don't respond to excessive levels of RF "radiation", which may interfere with their operation.
I put "radiation" in quotes, as it's TEM (Transverse Electro-Magnetic) radiation i.e. Radio Waves.

In the US, who knows?

This is about "Smart Meters" - again! I've recently seen a surge in Facebook statuses about Smart Meters. I posted a technical article about these devices in Smart meters. Even after I posted a link on Facebook to my article, links to alarmist pages still appeared. The latest one is The Great “Smart Meters” Hoax. Electromagnetic Fields Are Real And Dangerous To Our Health, where Sam Milham, MD, MPH epidemiologist & researcher tells us how things really are.

Unfortunately, he's talking shite. The problem with people talking alarmist shite on the internet is that people who read alarmist internet shite and who are ignorant of the subject, believe it! This causes Fear, Uncertainty & Doubt (FUD), which in turn causes chronic worry. Chronic worry causes chronic hypercortisolaemia, which isn't good. A placebo (e.g. wrapping aluminium foil around your Smart Meter or paying for a "proper" solution to the non-existent problem) alleviates the chronic worry, which improves health.

I don't know about US Smart Meters. For all I know, some eejit has designed them to transmit 1,000W of RF (I'm just being silly), to get an outdoor range of >100miles. As these devices are designed for short-range communication, they probably transmit up to 100mW (about the same power level as WiFi) to get an outdoor range of ~150m. 1mW is one thousandth of a Watt. Transmitting more power than is necessary increases the probability of interference to other electronic devices.

100mW is a lot lower than the power transmitted by mobile phones (up to 2,000mW for the 850/900MHz Vodafone/O2 network), which need to be able to reliably communicate with the nearest mast, which may be miles away. As mobile phones constantly transmit occasional bursts of RF (to let the network know that they are on) and they are either in a pocket or are held against the ear/in front of the face to make/receive calls etc (while transmitting regular bursts of RF) and they are safe to use, how can a Smart Meter which is transmitting a much lower power level at a much greater separation be harmful? It can't.

With WiFi, Equivalent isotropically radiated power (EIRP) in the EU is limited to 100mW. Dunno about the US. Bluetooth is very-low-power (~1mW for Class 3 devices).

So stop worrying! Chronic worry (also, reading alarmist internet shite) is bad for your health.

Finally, I noticed that Evelyn Kocur "liked" an article that I'd read and completely forgotten about. It's Evidence From the Metabolic Ward: 1.6-2.4g/kg Protein Turn Short Term Weight Loss Intervention into a Fat Loss Diet. Interestingly, the protein intake for optimum body recomposition is 1.6-2.4g/kg LBM. This is equivalent to ~1g/lb LBM, which is the protein recommendation given by Lyle McDonald in his Rapid Fat Loss Handbook. Yup, Lyle was right all along. That amount of protein isn't bad for the kidneys (even 50% more protein than that, isn't bad for the kidneys).

Rabu, 28 Maret 2012

Smart meters.

I was chatting to Kerrie's mum the other day and she was worrying about Smart meters. These are utility (usually electric) meters that can communicate their readings via radio waves & the internet to the utility companies to allow them better control of their generation plant. She'd been surfing the internet and had found sites warning about cancer and other health problems caused by the radiation from Smart meters. These sites are creating fear, uncertainty and doubt in order to sell solutions to problems that don't exist. Oh, dear.

Warning! Radio Frequency (RF) engineering stuff:-

See the graph below?

The horizontal axis is incorrectly labelled. Distance (d) is in metres (m), not kilometres (km).

Trust me. I know what I'm talking about. I was an RF design engineer for 29 years. See my CV.

The vertical axis is path attenuation (loss) in decibels (dB).

Decibels 101: Power loss in dB = 10 x LOG10 of the loss as a fraction.

A power loss of down to One tenth = 10dB. One hundredth = 20dB. One thousandth = 30dB. One millionth = 60dB. One million millionth = 120dB. One half = 3dB. One quarter = 6dB. One eighth = 9dB. Got it?

Smart meters transmit at frequencies from 900MHz (Vodafone & O2) to 1.9GHz (Orange & T-mobile etc). I mentioned mobile phone networks, as people don't seem to mind having mobile phones glued to their ears for long periods of time.

If you stand 4 metres away (at the end of someone's garden path, say) from a Smart meter fitted to their house & operating at 900MHz, there's a path loss of 29dB. The RF energy reaching you is 1/800th of that emitted by the meter. Also, the meter doesn't produce RF energy all of the time. The duty cycle is 1% to 5% i.e. RF energy is only produced for 1/100th to 1/20th of the time.

In conclusion, even if you stand with your nose touching the glass window of a Smart meter, you get less RF radiation (RF radiation is Transverse Electromagnetic Radiation a.k.a. radio waves and not ionising radiation as from radioactive materials) than from your mobile phone.

Are you feeling reassured, now? My work here is done!