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Rain Drops Signal Cell Phones

Zonk posted more than 8 years ago | from the re-using-technology dept.

86

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.'"

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86 comments

what was that? (5, Funny)

celardore (844933) | more than 8 years ago | (#15276072)

Sorry what was that? The signals patchy, with some sunny spells towards the afternoon...

doesn't poor weather increase signal strength? (1)

catmistake (814204) | more than 8 years ago | (#15277159)

I thought low cloud cover actually increased signal strength...? The signals bounce back and forth from the earth to the clouds, instead of travelling up out of the atmosphere... like CB sidebanding (if I understand that correctly)

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

Re:doesn't poor weather increase signal strength? (2, Informative)

tylernt (581794) | more than 8 years ago | (#15277845)

Cell phones operate at 900MHz and 1.8-1.9GHz, which do not skip off the ionosphere (as CB does at 29MHz). Skip is related more to radio frequency and the 11-year sunspot cycle than modulation (i.e., CB's AM vs. SSB [Single Side Band]). Additionally, water droplets tend to reduce signal strength, which is why satellite dish owners sometimes experience "rain fade".

The only explanation that I can think of for increased signal strength would be the tower antenna's or radio's temperature due to a poor quality installation. Hotter temps (as when the sun is shining on it) can reduce radio performance. I must admit that's a stretch, though.

Lots of possibilities (1)

marcus (1916) | more than 8 years ago | (#15287298)

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? ;-)

Headline? (5, Insightful)

Anonymous Coward | more than 8 years ago | (#15276079)

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.

Re:Headline? (3, Insightful)

Loconut1389 (455297) | more than 8 years ago | (#15276116)

They either meant "Rain Drops Cell Phone Signals", "Rain Drops Signal of Cell Phones" or "Measuring Rainfall With Cell Phone Signals"

Re:Headline? (5, Funny)

$RANDOMLUSER (804576) | more than 8 years ago | (#15276167)

Actually, they meant "Fireplace Ladder Telephone Sandwich Tree".

Re:Headline? (0, Redundant)

Gunnut1124 (961311) | more than 8 years ago | (#15276186)

This is the funniest thing I've read so far today... great job.

Mr. West... (1)

corychristison (951993) | more than 8 years ago | (#15276350)

... do you have any words for our viewers?

Box.
Toaster.
Aluminum.
Maple syrup. No I take that one back... I'm gonna hold on to that one.

Thank you Mayor West...

Re:Headline? (1)

tomcres (925786) | more than 8 years ago | (#15276729)

Keep an eye out for the next R.E.M. single... They might use that as lyrics..

I guess we should all just be glad that... (1)

Nick Driver (238034) | more than 8 years ago | (#15277223)

...the subject line wasn't something like:

    "Cohesive adamant sanction"

and the body of the article wasn't a viagra/cialis spam.

Re:Headline? (1)

diesel66 (254283) | more than 8 years ago | (#15277346)

No no no, it's spelled, "Raymond Luxury Yacht," but it's pronounced, "Throat Warbler Mangrove".

Re:Headline? (1)

Ohreally_factor (593551) | more than 8 years ago | (#15276235)

It's easy to figure out if you just try some word substitution:

"Gum Drops Signal Cell Phones"

"Eye Drops Signal Cell Phones"

"Cough Drops Signal Cell Phones"

Er, wait . . .

Re:Headline? (1)

ModernGeek (601932) | more than 8 years ago | (#15277850)

These weird headlines remind me of this article [slashdot.org] . Instead of writing to report a story accurately, people only care about getting the right keywords in there so that their page can get indexed. It's like the headline is just a bunch of keywords put together so that if someone searches for rain drops, this will appear. We should be writing to report, not writing to enhance page rank. The headline is just saying, "the rain drops are signaling the cell phones". As time goes on, we will have more and more terrible writing skills and reading comprehension. We need to take our kids off of the internet, and put them behind books until their at least 17.

Re:Headline? (1)

kimo123 (856805) | more than 8 years ago | (#15279185)

Um, have you ever read Hollywood's Variety magazine? They were doing keywords before tagging was invented. http://www.variety.com/ [variety.com]

Re:Headline? (1)

GraemeDonaldson (826049) | more than 8 years ago | (#15280858)

Dear Mr. High-And-Mighty

That's they're, not their. Perhaps you should follow your own advice?

:-)

Re:Headline? (5, Funny)

Elemenope (905108) | more than 8 years ago | (#15276153)

That's why I generally don't bother anymore. I just skip to the synopsis, which, while often containing lies, damned lies, distortions, exaggerations, editorial, and occasionally even statistics, is usually nevertheless not gibberish. Why spend ten seconds confused when you could be spending twenty seconds disgusted?

Article headline is backwards... (0)

Anonymous Coward | more than 8 years ago | (#15276196)

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...

You need to read between the words... (2, Funny)

pieterh (196118) | more than 8 years ago | (#15276203)

"Rain Drops Signal Cell Phones" really means:

"I'm zonked, it's late, and I'm going to copy and paste

Re:You need to read between the words... (0)

Anonymous Coward | more than 8 years ago | (#15280466)

"I'm zonked, it's late, and I'm going to copy and paste"

Don't you mean:

"I'm Zonk, Ed, it's late, and I'm going to copy and paste"

Re:Headline? (1)

gEvil (beta) (945888) | more than 8 years ago | (#15276325)

As I read the headline, there are three words that can be used as either verbs or nouns (rain, drops, signal. However, it appears that Zonk, in his infinite editorial wisdumb is using them all as nouns, which means there's no verb in there at all. Even if 'signal' is used as a verb, the headline still says the exact opposite of what the BBC article headline says, as someone else pointed out below. The quality on this site is appalling, yet it's still better than most tech sites out there. I find this very disturbing.

Re:Headline? (1)

njchick (611256) | more than 8 years ago | (#15278044)

Slashdot also has "NASA Hacker Gary McKinnon Interviewed" in the Science section, about a person who never worked for NASA, and who is arguably not a hacker at all.

turbo button for cell phone reception (1)

mmmiiikkkeee (930217) | more than 8 years ago | (#15276093)

"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 :)

Re:turbo button for cell phone reception (5, Informative)

Gordonjcp (186804) | more than 8 years ago | (#15276148)

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.

Re:turbo button for cell phone reception (1)

Gnavpot (708731) | more than 8 years ago | (#15276191)

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??
Probably to avoid interference with other nearby phone cells using the same frequency.

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.

Re:turbo button for cell phone reception (3, Informative)

AlecC (512609) | more than 8 years ago | (#15276369)

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

Re:turbo button for cell phone reception (1)

painQuin (626852) | more than 8 years ago | (#15276705)

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.


It's not a very good joke, though, is it...

Re:turbo button for cell phone reception (1)

jacksonj04 (800021) | more than 8 years ago | (#15276280)

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.

Re:turbo button for cell phone reception (3, Informative)

acidblood (247709) | more than 8 years ago | (#15276454)

A post this badly written doesn't really deserve a response, but here goes:

  • CDMA (I don't know about GSM) has dynamic power control built in, so that transmission power is kept at the bare minimum required -- why use more power if it isn't really required?
  • Extra power drains batteries faster.
  • May interfere with neighboring cells.
  • In a spread spectrum system (both 3G standards use spread spectrum, so this will apply to most networks in the near future), every transmission occurs on the same frequency band, so someone raising their power level is seen as noise on the other communications, which in turn requires everyone to raise their power level.

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.

The weatherman? (5, Funny)

RealGrouchy (943109) | more than 8 years ago | (#15276095)

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>

Re:The weatherman? (2, Insightful)

joe 155 (937621) | more than 8 years ago | (#15276109)

it reminds me of a quote that I read the other day about the problem with weather forecasts: It is right far too often for us to ignore it, but wrong far too often for us to rely on it. And mobile phone... they cut off too much to even be used as a full time emergancy phone, maybe this is just a way of getting twice the problems. Also it would look like it was always raining over my mum's house, she seems incapable of getting or keeping a signal... so it won't be perfect

Re:The weatherman? (1)

paRcat (50146) | more than 8 years ago | (#15276289)

You don't need a cell phone to know which way the wind blows. ...please tell me someone gets that

Re:The weatherman? (1)

Phronesis (175966) | more than 8 years ago | (#15277996)

You better stay away from those who carry round a firehose.

Re:The weatherman? (1)

paRcat (50146) | more than 8 years ago | (#15278660)

thank you. :)

Can't grok headline (3, Interesting)

What'sInAName (115383) | more than 8 years ago | (#15276098)


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.

Re:Can't grok headline (1)

Pete Brubaker (35550) | more than 8 years ago | (#15276118)

Yeah, I'm with you. I read it a couple times and it still doesnt make sense. :)

Re:Can't grok headline (1)

Zaatxe (939368) | more than 8 years ago | (#15276137)

Maybe it's just me but I'm having trouble parsing the headline.

No, it is not just you... I thought it was just me too, but that's because english isn't my first language. Actually, it's my third language. Almost fourth.

Re:Can't grok headline (1)

StarkRG (888216) | more than 8 years ago | (#15276172)

I think perhaps the problem here is arrangement. "Drops" is supposed to be the action. "Cell phones" needs to be singular and before "signal". It's telling you what kind of singal it is ("Rain drops signal" is a perfectly good sentance, but it doesn't give you enough info). As it stands now it seems like "Rain Drops" are "signal" -ing the "cell phones", instead of "Rain" "drop" -ping the "cell phone" "signal".

Or perhaps "Rain Drops Cell Signal" would be better...

Re:Can't grok headline (1)

fatduck (961824) | more than 8 years ago | (#15276315)

What happen ? Somebody set us up the bomb. Rain drops signal. What ! Cell phones turn on. It's you !! How are you gentlemen !! All your calls are belong to us. You are on the way to distortion. What you say !! You have no chance to survive make your call.

Spans the globe? (3, Insightful)

Wild Wizard (309461) | more than 8 years ago | (#15276111)

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.

Re:Spans the globe? (1)

Kumkwat (312490) | more than 8 years ago | (#15276210)

The parts of Australia that don't have cell ph. coverage, are either, desert, most of central australia, and therefore no rain. Or jungle, northern queensland, northern territories, which rain all the time! :)

water (1)

grahamsz (150076) | more than 8 years ago | (#15277161)

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.

So you're telling me... (0)

bort27 (261557) | more than 8 years ago | (#15276117)

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.
Okay, so the cell phone providors can boost their signal strength whenever they want? Then why don't they just do that all the bloody time? I'm sick and tired of my mobile Internet connection randomly disconn(S&*(*S&(DH*&(SD*HS&D*H NO CARRIER

Re:So you're telling me... (1)

Omni-Cognate (620505) | more than 8 years ago | (#15276270)

I think if they have the signal too high in good conditions, the base stations start interfering with each other.

Re:So you're telling me... (1)

It'sYerMam (762418) | more than 8 years ago | (#15276302)

Because that would require more power and cause interference. More to the point, individual areas of low signal are not really under the control of the providors - they control the network, not the geography and town planning.

Re:So you're telling me... (2, Funny)

Ohreally_factor (593551) | more than 8 years ago | (#15277227)

My cellular provider goes to 11.

Can you Hear me now (2, Funny)

SurfSlade (967547) | more than 8 years ago | (#15276132)

Turns out the Verizon's "Can you hear me now" guy is a meteorologist after all.

How dare you post stories on the shabbat!!!!! (-1, Troll)

Anonymous Coward | more than 8 years ago | (#15276134)

You're all anti-semitic. Anti-semitic I tell you!

Nice cover for military radar - Celldar (0, Troll)

AHuxley (892839) | more than 8 years ago | (#15276144)

Meteorological services or cover for a fun new military radar set?
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.asp [roke.co.uk]
http://en.wikipedia.org/wiki/Passive_radar [wikipedia.org]
http://www.findarticles.com/p/articles/mi_m0EKF/is _33_48/ai_90445280 [findarticles.com]

Detect rain... and anything else that blocks signa (1)

noidentity (188756) | more than 8 years ago | (#15276147)

"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?

Re:Detect rain... and anything else that blocks si (3, Interesting)

RubberDogBone (851604) | more than 8 years ago | (#15276871)

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.

Re:Detect rain... and anything else that blocks si (2, Interesting)

PeterBrett (780946) | more than 8 years ago | (#15277045)

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.

Not entirely true. From Wikipedia:

According to Wesley Clark and other NATO generals, Yugoslav air defences tracked F-117s with old Russian radars operating on long wavelengths. This, combined with the loss of stealth when the jets got wet or opened their bomb bays, made them highly visible on radar screens. The pilot survived and was later rescued by NATO forces.

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.

Sounds good...but how? (2, Interesting)

Zaphod2016 (971897) | more than 8 years ago | (#15276152)

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?

This really is utter crap. (0)

Anonymous Coward | more than 8 years ago | (#15276182)

More hyped and bogus 'research' from Israel, another non-story posted by Zonk.

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-breakth rough-of-some-kind it's essentially impossible.

I wish they'd go peddle their money-hungry pseudoscience elsewhere.

Re:Sounds good...but how? (1)

Amouth (879122) | more than 8 years ago | (#15276601)

my guesse .. they looked out side???

j/k

Re:Sounds good...but how? (1)

Firehed (942385) | more than 8 years ago | (#15277046)

They call someone who'd been standing outside when the data were gathered.

More accurate? (1, Interesting)

Anonymous Coward | more than 8 years ago | (#15276160)

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.

Re:More accurate? (0)

Anonymous Coward | more than 8 years ago | (#15277789)

Isnt this research kinda a waste and idiotic to begin with because it "predicts" CURRENT weather conditions? Anyone with a window to look out of can do that.

Feature Creep. (4, Funny)

RoffleTheWaffle (916980) | more than 8 years ago | (#15276180)

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.

Re:Feature Creep. (1)

Inda (580031) | more than 8 years ago | (#15276393)

Bullets and a trigger. Please please please. It could solve so many problems. Divert to mailbox? This button?

Ooops.

Only in America.

Re:Feature Creep. (1)

Ohreally_factor (593551) | more than 8 years ago | (#15277253)

I like the way you're looking at convergence. The iPod Glock: 10,000 songs. 11 bullets.

Re:Feature Creep. (1)

TubeSteak (669689) | more than 8 years ago | (#15278486)

Well, if they could figure out how to stuff a tiny barometer in the next generation of phones, meterologists could have some fairly fine grained data to play with.

I'm not sure how useful it'd be, but more data can't hurt.

P.S. TFA isn't about cell phone handsets, it's about the cell towers & other bits of wireless infrastructure.

Re:Feature Creep. (1)

RoffleTheWaffle (916980) | more than 8 years ago | (#15279345)

I know it's about the towers and such, I was just making a joke about seemingly useless features that've found their way into phones.

If you think about it, though, it shouldn't be especially difficult to cram a tiny barometer, thermometer, and humidity gauge into a handset. Creating a dongle for a phone that has all that and more would be a similarly painless process, and it could allow meteorologists and plain ol' hobbyists alike to carry around a tiny weather station wherever they go. This would be really useful for things like micro-climate research and all that fun stuff, but I can't say the average cell-phone owner would find a lot of use for it. (Unless, of course, you lived in a place like Indiana or Washington where the weather changes every five minutes. Then, Mr. Sunshine can't pull one over on you, like he likes to do whenever I try to mow my lawn. For the record, mowing in a rain-storm sucks.)

What would be really neat, though, is to pack a tiny doppler radar into a phone, like a little gizmo that fits over the antenna and spins around and uses the actual antenna to scan or something. Sure, it'd suck, but think of all the fun you could have with that kind of stuff besides watching the weather. You could run up to your friends and be like, "Hey, I've got you on my radar!" And then, you hit the built-in stop-watch feature of your crazy ass new phone and count the seconds before one of them punches you in the balls for being a dork.

Wave of the future, man.

You forgot cellphones use as (0)

Anonymous Coward | more than 8 years ago | (#15280366)

vibrators

Really? (1)

zaguar (881743) | more than 8 years ago | (#15276213)

The team's method exploits the fact that the strength of electromagnetic signals is weakened by certain types of weather and particularly rain.

What do you mean? I'm typing this on my Nokia phone in the rain and it's doing fin#$@^%@#%#@@!#NO CARRIER

Maybe we should replicate these results... (1)

Atario (673917) | more than 8 years ago | (#15276229)

...using DSS rain fade [tech-faq.com] .

Nuff said. (1)

Vo0k (760020) | more than 8 years ago | (#15276231)

Only means how hopelessly horrible their dedicated weather sensing hardware is.

Did you know (3, Interesting)

Hemi Rodner (570284) | more than 8 years ago | (#15276269)

that the cellular coverage rate in Israel is bigger than 100% because many people own more than one cellular?

Re:Did you know (1)

turbofisk (602472) | more than 8 years ago | (#15276574)

that the cellular penetration rate in Israel is greater than 100% because many people own more than one cellular?

10x (1)

Hemi Rodner (570284) | more than 8 years ago | (#15285207)

Thanks for the correction.

Old Story -- Prior Art (1, Informative)

Anonymous Coward | more than 8 years ago | (#15276282)

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!

Details of TFA--it uses the backhaul link (4, Informative)

dtmos (447842) | more than 8 years ago | (#15276294)

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 [etsi.org] ).

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 [telesat.ca] 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.

*sigh* (1)

dtmos (447842) | more than 8 years ago | (#15276300)

Ah, that would be, "meteorological" and "supplemental."

Sorry, rented fingers.

Geez.

Re:Details of TFA--it uses the backhaul link (1)

kawika (87069) | more than 8 years ago | (#15276865)

Yep, measuring handset attenuation would be pretty tricky. Since signals are weaker inside a building, which is where people often go when it rains, you'd expect to see a signal dropoff on rainy days. But it wouldn't necessarily be directly related to the rain intensity at that moment.

How did they substantiate the claim (3, Interesting)

mapkinase (958129) | more than 8 years ago | (#15276318)

that this method is "more accurate" than gauging and especially radar? I did not find it in BBC article and I do not have access to full text in Science, but the abstract [sciencemag.org] says:

The global spread of wireless networks brings a great opportunity for their use in environmental studies. Weather, atmospheric conditions, and constituents cause propagation impairments on radio links. As such, while providing communication facilities, existing wireless communication systems can be used as a widely distributed, high-resolution atmospheric observation network, operating in real time with minimum supervision and without additional cost. Here we demonstrate how measurements of the received signal level, which are made in a cellular network, provide reliable measurements for surface rainfall. We compare the estimated rainfall intensity with radar and rain gauge measurements.


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).

Re:How did they substantiate the claim (1)

geoffspear (692508) | more than 8 years ago | (#15276540)

From the Science article:

The skill of our method (correlation with rain gauges) is 0.86 for a 15-min-interval rain intensity and 0.9 for an hourly interval, versus 0.81 and 0.85, respectively, for radar, when evaluated from the maximal value over a 3 x 7 km2 area.

Re:How did they substantiate the claim (1)

mapkinase (958129) | more than 8 years ago | (#15277092)

So, in other words, "cell" method beats radar in terms of accuracy in a rainfall estimate for a point area compared, of course, to gauge, which is in this case apparent standard and it beats gauge in coverage compared to the radar for obvious reasons. I guess the first one was non-trivial to guess.

wsr-88d radar rainfall estimates link (0)

Anonymous Coward | more than 8 years ago | (#15278902)

http://www.srh.noaa.gov/rfcshare/precip_analysis_n ew.php?duration=day&location=GA&product=obs&archiv e=no [noaa.gov]

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. /me waits for the day someone figures out how to get ultra-sensitive microwave wavelength microwave sensors out on a geostationary satellite.

Weird title. (3, Funny)

Vo0k (760020) | more than 8 years ago | (#15276375)

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.

Re:Weird title. (1)

AndroidCat (229562) | more than 8 years ago | (#15277655)

Could you hold? The rain drops are on the other line.

with Apologies to Burt Bachrach and Hal David (1)

Phronesis (175966) | more than 8 years ago | (#15280387)

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.

Not new, not even old, it's ANCIENT NEWS (3, Informative)

Ancient_Hacker (751168) | more than 8 years ago | (#15276434)

IIRC when Bell Labs was experimenting with microwaves, circa 1939, they noticed their signals were a LOT weaker when the weather was humid.

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!

Re:Not new, not even old, it's ANCIENT NEWS (0)

Anonymous Coward | more than 8 years ago | (#15276662)

No, it's not new. But this is yet another case of "Israel Science Promotion" (no that's not a troll. Keep reading).

Look at most science stories we get - they are invariably stories of Israeli researchers doing things that, when we read in depth, are not new or innovative but merely representative of what many other researchers all over the world are doing.

The problem is that Israel (and Australia, the other culprit for Country-Specific Science Promotion) have a PR-associated effort to promote themselves to the media. Both Australia and Israel think this is will help to get investment from worldwide sources because they establish mindshare and develop themselves as a science "brand".

Quite frankly, it's annoying though. For all the science stories we get, about a third to a half are composed of "Israeli scientists..." or "Researchers in Australia...". And once we get beyond the hype we see that it is really nothing special or new or great - it's just hype that international media is falling for, and free advertising. I have given up on reading any stories about research by Israeli or Australian researchers - I figure the real breakthroughs that are given media attention are almost certainly from a country without their own PR push.

Re:Not new, not even old, it's ANCIENT NEWS (1)

Zachary Kessin (1372) | more than 8 years ago | (#15278325)

That rain affects radio signals is not news this has been known for a long time. That you can use this effect to quantify rainfall in a very localized way is. Now for those of you who have never been here Israel is a desert. (Some parts more than others) and there is normally no rain between April and September so when it does rain we want to make the best possible use out of it. If the country can get 5% more productive use out of each rain fall that will really help out a huge amount. Israel has invested a huge amount of money into our water infrastructure over the last 58 years and will continue to do so.

The shape of raindrops (2, Informative)

Anonymous Coward | more than 8 years ago | (#15277149)

Here goes a curious fact about the shape of raindrops and its effect on radio waves.

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/91 232/1 [suite101.com]

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.

How do they know? (1)

AK__64 (740022) | more than 8 years ago | (#15278215)

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.
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