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Rain Drops Signal Cell Phones
An anonymous reader writes "Signals from mobile phone masts have been used to measure rainfall patterns in Israel, scientists report. From the BBC article: 'The University of Tel-Aviv analyzed information routinely collected by mobile networks and say their technique is more accurate than current methods used by meteorological services. The data is a by-product of mobile network operators' need to monitor signal strength. If bad weather causes a signal to drop, an automatic system analyzing the data boosts the signal to make sure that people can still use their mobile phones. The amount of reduction in signal strength gave the researchers an indication of how much rain had fallen.'"
Sorry what was that? The signals patchy, with some sunny spells towards the afternoon...
Is it just me, or are the headlines for some articles just downright incomprehensible?
What does "Rain Drops Signal Cell Phones" actually mean? Are individual raindrops sending signals to cell phones? Did they actually mean that rain drops (degrades) cell phone signals? No, apparently they meant that cell phone signals can detect rain drops... and unless my ability to parse english is somewhat broken, the headline simply doesn't say that.
I wouldn't mention this if it didn't happen at least once a week. I'm forced to spend a good ten seconds in a state of frustrated confusion as my brain struggles to comprehend absolute gibberish.
"boosts the signal to make sure that people can still use their mobile phones."
:)
i did not know they coudl boost the signal any more then what it was at.... i kinda figured they would already have it as high as they could. i mean why woudl they not jsut keep the signal "boosted" all the times soem places still have dead zones so that coudl help some?? it would be like thouse old computers with the turbo button.. but for ur cell phone reception
I always knew not to trust the weatherman, but you're telling me to trust the cell phone people now? I don't think I can handle *that*.
- RG>
Hey pal, this isn't a pleasantforest, so don't waste my time with pleasantries!
Maybe it's just me (I'm up at 5:30am to catch a flight) but I'm having trouble parsing the headline. Sounds like the rain is signaling cell phones.
Kind of interesting, but (having not read TFA, mind you) I wonder how small amounts of rain affect the signal. One would thing the signal would only be affected by heavy rain, and so the resolution of the resulting data would suffer.
But the information necessary for this novel approach is effectively free, continuous and comes from a dense network of masts that already span almost the entire globe.
Oh really, these people need to get a clue, down here in Australia the mobile networks cover absoultely crap all of the continent and my moneys on Africa, South America, Asia (The real asia which is freaking huge) and Sibera are pretty much in the same boat.
And don't get me started on the 2/3rd of the planet is covered in water bit.
Free, Anonymous surfing: Pagewash.com.
Turns out the Verizon's "Can you hear me now" guy is a meteorologist after all.
Google for cell phone radar ppl eg. Celldar
Cheap, always on, very hard to kill, nice world wide exports.
If it is targeted, you have the best PR ever?
http://www.roke.co.uk/sensors/stealth/celldar.asps _33_48/ai_90445280
http://en.wikipedia.org/wiki/Passive_radar
http://www.findarticles.com/p/articles/mi_m0EKF/i
Domestic spying is now "Benign Information Gathering"
"The amount of reduction in signal strength gave the researchers an indication of how much rain had fallen."
What about fog? What about different sized rain droplets and velocities and differing amounts of signal boost necessary for the same volume of water? Can the cell tower differentiate between signal loss due to rain as compared to objects near the phone, like a car body or metal object?
Well, there's an upper legal limit on effective transmitted power, but often a sector is run at lower power to reduce interference with neighbouring sectors.
If you find you're getting a drop in signal due to rain fade, you can bump it up a bit. Most stuff uses ATPC (automatic transmit power control) so does it by itself, but you can get graphs off it with SNMP.
From TFA: The scientists believe the technique can also measure snowfall, hail or fog [...] The data is a by-product of mobile network operators' need to monitor signal strength [...] If bad weather causes a signal to drop, an automatic system analysing the data boosts the signal to make sure that people can still use their mobile phones.
I follow the logic- except for one catch: how can researchers tell if the signal strength is reduced by rain OR snow OR hail (etc)?
In other words, bad weather = signal strength affected. Got it. But how do we go from that to distinguishing which form of bad weather caused the signal loss?
barack to the future?
They say they are more accurate than the regular met services ... and they measured this how?
A dense fog and a light rain have the same effect on signal strength. Maybe they don't get fog.
I had the opportunity to visit the control center for one of the national cell phone providers. It was a large room with large screens covering one wall. Some of the screens were weather maps. They used the weather predict where there would be degredation in the service.
First, cellular phones were just that - cellular phones.
Then came the ringtones and other customization features, and those were fun to toy with.
Then there was web-browsing, which was even cooler, and actually served to make the phone more useful.
Then came the cameras for still-image and video capture - why for nobody knows, but people love it anyway.
Given all of that neat stuff, and the increasingly computer-like nature of cellular phones, what's the next feature on the horizon, you ask?
Portable weather stations. It just makes sense.
More hyped and bogus 'research' from Israel, another non-story posted by Zonk.
h rough-of-some-kind it's essentially impossible.
Using emission-based means to differentiate between fog, rain, snow and other forms of precipitation and aerosols is difficult at the best of times. With the methods discussed in this sponsorship-seeking-blather-disguised-as-a-breakt
I wish they'd go peddle their money-hungry pseudoscience elsewhere.
This is pure guesswork on my behalf, but here goes:
I would imagine that the cell network is laid out so nearby cells use different frequencies within the allowed spectrum. This would prevent one cell phone or phone cell from interfering with the communication between another cell phone and phone cell.
Under good conditions, a signal with unchanged strength will reach farther, thus perhaps causing interference with far away cells. This would be a good reason for reducing the signal strength under good conditions.
Actually, the phone itself will also reduce transmission strength under good conditions. It is an old joke that if you want to avoid brain cancer, you should live near to a phone cell so your own cell phone doesn't have to turn up the transmission strength.
The actual BBC article headline is "Mobile masts signal rain showers" - this is the exact reverse of the Slashdot article "Rain Drops Signal Cell Phones" - weird...
"Rain Drops Signal Cell Phones" really means:
"I'm zonked, it's late, and I'm going to copy and paste
My blog
What do you mean? I'm typing this on my Nokia phone in the rain and it's doing fin#$@^%@#%#@@!#NO CARRIER
"Sure there's porn and piracy on the Web but there's probably a downside too."
...using DSS rain fade.
"A great democracy must be progressive or it will soon cease to be a great democracy." --Theodore Roosevelt
Only means how hopelessly horrible their dedicated weather sensing hardware is.
Anagram("United States of America") == "Dine out, taste a Mac, fries"
that the cellular coverage rate in Israel is bigger than 100% because many people own more than one cellular?
hemi
On the actual handset, it will only use as much power as it needs to get a signal. If you're in a zone with really crap reception, your handset will ramp up its signal power to try maintain contact. Conversely, if you're only a few hundred metres from a cell tower, it uses hardly any.
I can only guess that for towers the power alters based on an average of the signal strength to all its handsets, so it is also possibly to save power on the handsets. As for interference, there's no point keeping each tower up too high because handsets which would be best served by another cell would be handing over too late since they could keep in contact with their original tower. Even more extreme, if you're on parts of the English coastline you get charged international rates because your phone picks up signals from French towers stronger than UK towers.
How many people can read hex if only you and dead people can read hex?
In the late 1930's Robert Watson Watt was investigating the interference of thunderstorms with radio signals in order to warn of approaching bad weather. As we all know, this led ultimately to the discovery of radar. This story is just a modification of that technique. 1. Duplicate Prior Art with slight modification in frequency 2.**** 3. Profit!
The key point not brought out in TFA is that the rainfall prediction scheme is not based on the link from the handset to the cell tower, but on the wireless backhaul links of the cellular system. The backhaul link is the link from the cell tower to the rest of the world (or at least the phone system of the rest of the world)--in many places in the world it is fiber or some other line, but increasingly often it, too, is wireless, using something called digital fixed radio systems (DFRS; check out standard EN 301 751 at ETSI).
The wireless backhaul links are much better for the meterological application than the handset link, because:
(a) It's a fixed link; since the cell towers don't move, like the handsets do, the location of the link, and therefore the rain, is known, and
(b) It's at a much higher frequency. The DFRS links used in this paper are at 8-23 GHz, much higher than the 0.8-1.9 GHz (depending on your local regulatory environment) of the handset link. This is important because rain attenuation increases as the signal frequency increases; it would be quite difficult to reliably detect rain fades at the handset frequencies (although in a bad enough storm--a cyclone comes to mind--it's probably possible; TFA notes the anecdotal evidence of fading television signals in bad weather).
I note in passing that the web-based supplimental material to the article references a US patent application, # 60/698,491.
Ah, that would be, "meteorological" and "supplemental."
Sorry, rented fingers.
Geez.
No claims about accuracy as you see. Whoever have access to full text please provide some clue (by Monday when I will have the access, the topic will be gone, so please post now).
I do not believe in karma. "Funny"=-6. Do good and forbid evil. Yours, Oft-Offtopic Flamebaiting Troll.
Box.
Toaster.
Aluminum.
Maple syrup. No I take that one back... I'm gonna hold on to that one.
Thank you Mayor West...
Correct. The size of the cells used by telephones varies enormously, and hence the power to cover the cell properly also varies. In crowded areas with heavy cellphone use, such as city financial centres, the cells may be only 100 yards across. The power is turned doen so as to avoid invading nearby cells. On the other hand, in isolated regions, they want to make a few masts cover as much area as possible, so they turn up the power so the cells may be tens of miles across. But whatever power you are using, you don't want to be heard across an adjacent cell - the ideal is a small overlap bbetween adjacent cells but no crosstalk to cells beyond. So both masts and phones continuously adjust their power to be "just right". The rain signal discussed in this article is basically the level of this adjustment.
You can bet that when a phon is advertised as having "up to 240 minutes talk time", that means you get that talk time when standing very close to the mast and therefore using minimum power. In real use, you will be further away, need more power, and get less talk time
Consciousness is an illusion caused by an excess of self consciousness.
There are so many ways to rearrange the words in the title to make sense of the article, and they have chosen one that is plain dumb. Cell phones don't get signalled by rain drops, nor rain makes you drop cell phone meant to signal.
Rain drops drop cell phone signal.
Rain drops cell phone signal.
Rain signalled by cell phone signal drops.
Cell phone signal drops signals rain.
Cell phones signal rain drops.
Drop in cell phone signal signals rain.
and quite a few more.
Anagram("United States of America") == "Dine out, taste a Mac, fries"
So much so, that when they rolled out microwave telephone relay towers, circa 1950, they intentionally boosted the transmitted signal by some 20db (that's 100 times) more than necessary on a dry day, just to allow the signals to still get through during damp or fog or rain.
So this isnt even old news, it's going on 68 years!
Oh, and the turbo button actually slowed down the processor down to the speed of a 4.7 MHz 8086. When in turbo mode the computer would run at nominal speed.
Join the NFSNET. Our prime goal is making little numbers out of big ones. http://www.nfsnet.org/
It's not a very good joke, though, is it...
A guilty conscience means at least you've got one.
Would you like a prize? Have one. Indeed, cell signals have been used to track objects, like aircraft.
In particular, a US F-117 Stealth fighter was shot down over Bosnia. The shooters could not track the plane on radar -because it's stealth, you know- so they looked instead at the changing signal patterns of the cell system as the plane flew over.
They didn't look for the plane so much as the "signal hole" it made as it moved through the sky. They simply aimed some missles at the "hole" and scored a hit. It was the first F117 downed by enemy fire.
Very creative. Everydamnbody in the world who's likely to be F117 targets took lots and lots of notes.
Sig for hire.
Not entirely true. From Wikipedia:
The maths has also been done to show that you can use emissions from FM radio station transmitters and a pair of receivers (with a baseline of about a mile) to track F-117s easily (as long as you have enough computer power). This is one of the reasons that one of the first bombing targets in the Iraq war were civilian radio station transmitters.
The B2 doesn't suffer from this vulnerability -- it doesn't rely on geometry so much as materials that don't reflect radar radiation.
Pirate Party UK
Here goes a curious fact about the shape of raindrops and its effect on radio waves.
1 232/1
Many people think that raindrops have the typical shape of a tear, others think by looking at the rain itself that the drops are vertical lines of water. The first impression comes from pictures and literature, the second is caused by the fact that the raindrops fall at high speed, thus appear vertically blurred.
In fact, the tears start up being roughly spherical and end up becoming flat because of the air resistance.
http://www.suite101.com/article.cfm/science_sky/9
When these water drops are inside an electromagnetic field, electric currents are induced on its surface which attenuate the field. Due to the flat shape, it results that the horizontal component of the electric field is the one which gets attenuated most.
This means that in order to minimize attenuation in a radio link during rain, it is convenient to use "vertical polarization" (which means that the electric field vector at any point within the electromagnetic field is contained in the vertical axis only) which is the component of the electric field which is least attenuated by rain.
I live in the shadow of a mountain, and all I know is that on sunny cloudless day, my cell reception sucks; I'd swear its better when it rains. When its dry but overcast I get the strongest signals.
any /. physicists and cell pundits are welcome to explain... thanks
The Admin and the Engineer
I was very impressed in scandinavia that round the main shipping/ferry routes, every crappy little rock has a tower stuck on it so that you don't drop coverage when sailing between countries.
...the subject line wasn't something like:
"Cohesive adamant sanction"
and the body of the article wasn't a viagra/cialis spam.
How can they state that their measurements are more accurate than existing meterological infrastructure?
I mean besides setting up their own measuring stations and... Oh never mind.
http://www.srh.noaa.gov/rfcshare/precip_analysis_n ew.php?duration=day&location=GA&product=obs&archiv e=no
/me waits for the day someone figures out how to get ultra-sensitive microwave wavelength microwave sensors out on a geostationary satellite.
Radar rainfall estimates are out there, but I guess if you are lacking in the meteorological radar dept then their idea is something great to be looking into. One thing though...this probably won't help much out where there are no cell users.
vibrators
Rain drops keep signaling my phone
But that doesn't mean I'll pay their charges just to roam
Roaming's not for me
'Cause I can't talk on my phone from an airplane
The FCC
Keeps on hassling me
And rain drops keep signaling my phone.
Thanks for the correction.
hemi
As IAAPACP(I Am A Physicist And Cell Pundit), scattering and lensing are most likely, I think.
;-)
Visible light is not the only part of the EM spectrum that can be distorted by atmospheric conditions. Think mirage. Think radar. 1.8 GHz phones are definitely in the microwave class. Lensing with different layers of air with temperature and humidity variations might be your culprit. Think mirage where you are looking at the ground and see the sky or with your situation, your cellphone is "looking" over the mountain at the sky and can see a cell tower that is just over the hill on the other side of the mountain.
Finally, and don't laugh, consider human behavior. Perhaps when the weather is nice, you stand near the window or outside where the reception is better?
Good judgement comes from experience, and experience comes from bad judgement.
- W. Wriston, former Citibank CEO