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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.
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.
Turns out the Verizon's "Can you hear me now" guy is a meteorologist after all.
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?
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.
"Rain Drops Signal Cell Phones" really means:
"I'm zonked, it's late, and I'm going to copy and paste
My blog
that the cellular coverage rate in Israel is bigger than 100% because many people own more than one cellular?
hemi
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.
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.
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/
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.
My cellular provider goes to 11.
It's not offtopic, dumbass. It's orthogonal.
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.
DRM 'manages access' in the same way that a prison 'manages freedom'