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Rumors => EOS Bodies => Topic started by: 7enderbender on February 26, 2013, 01:27:18 PM

Title: Bodies and cell towers?
Post by: 7enderbender on February 26, 2013, 01:27:18 PM
Question to all our physics and engineering experts here: I found an interesting location that is at the top of a building with cell phone transmitters attached to it. I think they're for major US carriers in case the frequencies used make a difference.

The place has the usual warning signs a la "may exceed the usual blahblah". From a medical standpoint I'm certain that it's a no-issue. But what about camera gear? I guess I might not want to use wireless triggers there but anything else at risk?

Thanks
Title: Re: Bodies and cell towers?
Post by: Pitbullo on February 26, 2013, 01:46:02 PM
I put my camera (550D) in the X-ray machine at work the other day, and gave it a really really good dose of radiation. No harm at all to the camera. I donĀ“t think a cell tower should do any harm at all.

X-ray of 550D with Sigma 24-70 f:2.8
https://www.foto.no/cgi-bin/bilder/vis_bilde.cgi?id=686696 (https://www.foto.no/cgi-bin/bilder/vis_bilde.cgi?id=686696)
Title: Re: Bodies and cell towers?
Post by: Mt Spokane Photography on February 26, 2013, 04:24:20 PM
Its common to see a "Barber Pole" on the LCD if radio intereference is strong.  It won't damage your camera, but the rear LCD might have interference.  This has been reported by some users, but I've never seen it.
As far as cell phone radiiation damage, its a long term thing and dependent on the amount of exposure, and how susceptable you are, which is a unknown.  There will be no way to link it to any Cancer you might get in 15 or 20 years, but its a good idea to believe the signs.
Title: Re: Bodies and cell towers?
Post by: Don Haines on February 26, 2013, 08:35:24 PM
Not sure about the US, but in Canada areas with levels of RF that exceed "safety code 6" are required to be marked with radiation hazard signs and access to said areas is to be restricted. This level is well below what should harm electronics.

I'm supprised you have access to such an area....
Title: Re: Bodies and cell towers?
Post by: bvukich on February 26, 2013, 11:02:44 PM
If you do decide go, just stay as far away from the antennas as possible, and be mindful of the inverse square law.  Your exposure (and that of your equipment, but you can replace equipment) increases exponentially (I=1/d^2) as you get closer to the source. So for example, moving from 10m to 7m doubles your exposure, as does moving from 1m to .7m.  Conversely, moving from 10m to 14m cuts your exposure in half.

(awkward photography analogy follows, abandon all hope ye who enter here)

If it helps, think of it in terms of f/ stops.  Your starting point is f/1, reduce the distance (focal length if you will) by .7 (sqrt2/2) and you're at f/.7 and your exposure doubles (plus one stop), increase the distance by 1.4 (sqrt2) and you're at f/1.4 and your exposure is cut in half (minus one stop).

So say you want to reduce your exposure by 4 stops (1/16th the exposure), four stops from f/1 is f/4 so you want to be 4x farther away.  Six stops (1/64th the exposure) would be f/8 so eight times farther.

If that's confusing, just ignore it.  I explained it poorly, but it's the exact same law that governs both (inverse square law).
Title: Re: Bodies and cell towers?
Post by: wopbv4 on February 26, 2013, 11:17:52 PM
There are definetely healh related issues to electro magnetic radiation (=antenna's).
Therefore, there are safe distance limits, see attached file
Title: Re: Bodies and cell towers?
Post by: 7enderbender on February 27, 2013, 02:06:17 PM
There are definetely healh related issues to electro magnetic radiation (=antenna's).
Therefore, there are safe distance limits, see attached file

You're sure that that's "definitely"? I have yet to see anything that indicates that cell phone towers or cell phone use have any impact on humans whatsoever. Yes, there are the occasional "studies" that make the headlines in the main stream media but appear to be mostly questionable interpretation of data junk. I don't buy it. The various government regulations are totally random.

That's why I was interested on any potential harm to the camera gear. I'm not worried about myself.
Title: Re: Bodies and cell towers?
Post by: thepancakeman on February 27, 2013, 02:40:22 PM
There are definetely healh related issues to electro magnetic radiation (=antenna's).
Therefore, there are safe distance limits, see attached file

You're sure that that's "definitely"? I have yet to see anything that indicates that cell phone towers or cell phone use have any impact on humans whatsoever. Yes, there are the occasional "studies" that make the headlines in the main stream media but appear to be mostly questionable interpretation of data junk. I don't buy it. The various government regulations are totally random.

That's why I was interested on any potential harm to the camera gear. I'm not worried about myself.

It's your life, do what you want.  But I can tell you from personal experience EM fields can cause health problems: my wife had too high of exposure to one and now gets migraines being anywhere near even very low EM fields.  She can't even sit near a desktop computer (with the screen off) for more than about half an hour before she starts to feel ill.
Title: Re: Bodies and cell towers?
Post by: Rat on February 27, 2013, 02:40:56 PM
Definitely. Everybody (well, almost) knows you shouldn't microwave live animals if you don't want 'em to die - and this is the same sort of radiation. Of course, it is a LOT less radiation, but while your car isn't totalled, that doesn't mean you don't get scratches in the paint.

If bvukich can botch an metaphor, so can I! :P
Title: Re: Bodies and cell towers?
Post by: docholliday on February 27, 2013, 02:43:46 PM
It's non-ionizing radiation, so it's not as bad as sitting 20ft from a piece of cobalt-60. But, at higher frequencies, it is still microwave radiation. However, as the traces inside a piece of electronics are pretty much little antennas, enough EMF will cause it to cook sensitive MOS type chips. It would take quite a bit, or a long exposure, but usually won't hurt much.

The ol' turning on a hairdryer and watching the TV go static-crazy is a form of EMF interference, but much lower power and more random.

However, enough microwave radiation and it will vibrate your molecules enough to generate heat - kinda like cooking you from the inside out. Microwaves work by vibrating water molecules and making them generate heat via friction. Concentrating them inside a Faraday cage like structure (the oven) is what makes your food cook.

If you were to stand at a parabolic focal point near a metal structure (power cabinet, rack, etc) in line with the transmitter array, you'd probably take some damage, but that would take some careful focusing! Nevertheless, high enough power EMF can still distrupt nervous signals and interfere with body electrical functions.
Title: Re: Bodies and cell towers?
Post by: TrumpetPower! on February 27, 2013, 03:33:05 PM
Those signs aren't there for no reason.

Yes, microwave radiation is non-ionizing. But at high enough densities it'll cook you just as well as it'll cook your food.

I've heard multiple anecdotes from multiple people of idiots sticking parts of themselves in front of high-power microwave transmitters -- the exact same types of anecdotes as people looking down the barrel of a gun or "quickly glancing" at a high-powered laser or grabbing at a falling power tool. The one that sticks in my head is of a guy in the military putting his head in front of a waveguide while saying, "Hey, is this th--" and falling down dead with his hair on fire before he could finish the sentence.

The broadcast signals from the cell tower aren't going to do any harm to anybody, certainly not on the ground. But if the tower is using a focused microwave repeater to talk to another tower somewhere...yeah, that could certainly do some damage before you realize what's going on.

Me? I don't fuck with industrial equipment I'm not certified to operate, and that means not going where I'm not authorized to go and keeping my hands in my pockets and staying within the painted lines on the ground when I'm following my escort. Even if there's no doubt in my mind that whatever it is is safe. That goes for the auto mechanic, the bookbinder, the airfield, the construction site, wherever.

Cheers,

b&
Title: Re: Bodies and cell towers?
Post by: BumpyMunky on February 27, 2013, 03:47:17 PM

Not exactly a cell tower, but I worked at a Naval Base where a frigate (naval ship) came in with its tactical radar accidentally left on.   Played havoc with the tech in the offices and fried a number of computers.    That being said, the classified servers in the "Tempest" room (basically a Faraday cage) right next to where I sat went unscathed.  Lost touch with those working there, so no idea if there were lasting effects on the humans.  I seem to be <twitch> ok. ;)

As others have said, the frequency as well as the power have a large impact on how it affects different things.  Better to err on the side of caution on this one.

(BTW, tinfoil hats can sometimes form the shape of a parabola, so careful where you stick your head while wearing one...)
Title: Re: Bodies and cell towers?
Post by: Don Haines on February 27, 2013, 06:33:45 PM
There are definetely healh related issues to electro magnetic radiation (=antenna's).
Therefore, there are safe distance limits, see attached file

You're sure that that's "definitely"? I have yet to see anything that indicates that cell phone towers or cell phone use have any impact on humans whatsoever. Yes, there are the occasional "studies" that make the headlines in the main stream media but appear to be mostly questionable interpretation of data junk. I don't buy it. The various government regulations are totally random.

That's why I was interested on any potential harm to the camera gear. I'm not worried about myself.

That's right.... no impact on humans whatsoever..... I used to do a demo to new staff on the hazzards of RF..... when they see a hotdog cook in about 5 seconds they get the point.....

You don't have a clue if the antennas are Tx or Rx, you don't know the power levels, radiation pattern, duty cycle, or frequency. Only an idiot would go where there are warning signs and I am very suprised that the access is not locked. And don't assume that a big antenna is more dangerous than a small one.... for satcoms we run 200 watts into a 1.2 meter dish and 2 watts into a 9 meter dish...
Title: Re: Bodies and cell towers?
Post by: TrumpetPower! on February 27, 2013, 06:45:55 PM
I used to do a demo to new staff on the hazzards of RF..... when they see a hotdog cook in about 5 seconds they get the point.....

I'm sure there have to be online videos of that sort of thing, but a couple quick searches turned up only nutjobs worried about driving under high-tension power lines or using an iPhone on the subway or the like.

Anybody got any real links?

b&
Title: Re: Bodies and cell towers?
Post by: Don Haines on February 27, 2013, 07:13:17 PM
I used to do a demo to new staff on the hazzards of RF..... when they see a hotdog cook in about 5 seconds they get the point.....

I'm sure there have to be online videos of that sort of thing, but a couple quick searches turned up only nutjobs worried about driving under high-tension power lines or using an iPhone on the subway or the like.

Anybody got any real links?

b&
No longer have the 10Kwatt transmitter so I can't film it.... but this is what we used it for, beaming power to a small plane so that it never had to land to refuel.
http://www.friendsofcrc.ca/Projects/SHARP/sharp.html (http://www.friendsofcrc.ca/Projects/SHARP/sharp.html)
If it's enough power to fly a plane you can bet it's not a good idea to get in the way....
Title: Re: Bodies and cell towers?
Post by: Don Haines on February 27, 2013, 07:38:13 PM
Definitely. Everybody (well, almost) knows you shouldn't microwave live animals if you don't want 'em to die - and this is the same sort of radiation. Of course, it is a LOT less radiation, but while your car isn't totalled, that doesn't mean you don't get scratches in the paint.

If bvukich can botch an metaphor, so can I! :P

actualy..... your microwave oven is a lot less power than what is fed into a cell-phone node...
Title: Re: Bodies and cell towers?
Post by: brianboru on February 27, 2013, 08:25:50 PM
Wow was it hard to find a reference to the invention of the microwave oven from a reputable source that has the melting chocolate bar story:

http://www.ieeeghn.org/wiki/index.php/Microwave_Ovens (http://www.ieeeghn.org/wiki/index.php/Microwave_Ovens)

I remember my electro-magnetism prof mentioning as a soldier in WWII standing in front of radar installations to get warm. (He was a bit odd.)
Title: Re: Bodies and cell towers?
Post by: tpatana on February 27, 2013, 10:10:00 PM
So much info here that's not really accurate, some good also, but let me clarify a bit.

In general, you can't get too much on your body. If you can, you're doing something you shouldn't, like climbing on the tower, hugging the actual antenna element, or something similar. Especially if you're below the antenna level (more than say 20feet/6 meter), quite often the beam is directed above you, and the signal level is much less compared to same distance from the antenna but at same height than the antenna. That's not always the case, but usually. The antenna beam is formed that way to get maximum distance for the signal, no point beaming it to the ground close to the tower. Makes sense, right.

So #1, you're likely safe. 99% of the time you get more cell signal radiation from the one you hold on your ear, and that's why they have the SAR-test on the phones, with certain maximum limit they have to pass or FCC don't allow them to be sold. New phones are much much better on SAR than late-90 phones. So you're safe with your cell phone too. Unless you use the old POS from 90s, and they didn't kill anyone either.

As for equipment, it's still highly unlikely, but it is possible to get interference or even malfunction. Most electronics are tested towards certain type of radiation, both different frequency and power. On top of my head I can't recall the typical levels they test, but I think they are not that strong. So depending on the equipment, how well it was shielded and such, it might cause something if you are too close to the beam. Again, being below the tower helps compared to being same level with the antennas. Again, in most cases, not always.

I'm trying to think if it could cause permanent damage, but it should try to corrupt the FW in one way or another, and that's one step more difficult. So I'd say you're safe on both accounts, you and your gear, but if you see something odd behavior, turn off the camera and find position with less beam. Most likely you don't get anything.
Title: Re: Bodies and cell towers?
Post by: dbduchene on February 28, 2013, 09:14:45 PM


actualy..... your microwave oven is a lot less power than what is fed into a cell-phone node...
[/quote]

I do not know how you came up with this but it just is not true. Most Cell transmitters are 70 watts. at 800 Megs or 1.9 gig Microwaves are 800 to 1200 watts and highly focussed at 2.4 gig. (same as your wifi, Blue tooth and many other things) I made my living through most of the 90s climbing cell and other two way towers.

To the OP's question there is no way to answer your questions without knowing a lot of info that you do not have a way to provided us. It may be a bad place to be and it may be OK it just depends on a LOT of things. The chances of it doing something that would kill your camera is very low.

Title: Re: Bodies and cell towers?
Post by: Don Haines on February 28, 2013, 10:52:44 PM


actualy..... your microwave oven is a lot less power than what is fed into a cell-phone node...

I do not know how you came up with this but it just is not true. Most Cell transmitters are 70 watts. at 800 Megs or 1.9 gig
[/quote]
I was thinking peak and your number sounds about right for average.  I was told that the tower on site is peak power of 1000 watts per cell and the waveform has a peak to average ratio of 8db... That would make an average power during transmission of about 150 watts, and since it does not transmit continuously, and guessing a 50 percent duty cycle, that would be 75, your number being 70
Title: Re: Bodies and cell towers?
Post by: LetTheRightLensIn on March 01, 2013, 05:26:06 PM
Question to all our physics and engineering experts here: I found an interesting location that is at the top of a building with cell phone transmitters attached to it. I think they're for major US carriers in case the frequencies used make a difference.

The place has the usual warning signs a la "may exceed the usual blahblah". From a medical standpoint I'm certain that it's a no-issue. But what about camera gear? I guess I might not want to use wireless triggers there but anything else at risk?

Thanks

I drove up to Mt. Wilson, they have tons of transmitting towers up there. Got out walked around a bit. Went back to the car and used the clicker to try to unlock it, click, click, click, nothing! Even from 1" away NOTHING! Thank god it wasn't one of those cars that has no physical key mechanism or I would've be shafted. And it did make you wonder what was beaming on you up there. I've never had a key clicker fail to open something from a few feet away never mind still failing at just 1-2" inches away!

Title: Re: Bodies and cell towers?
Post by: Don Haines on March 01, 2013, 06:08:15 PM
Question to all our physics and engineering experts here: I found an interesting location that is at the top of a building with cell phone transmitters attached to it. I think they're for major US carriers in case the frequencies used make a difference.

The place has the usual warning signs a la "may exceed the usual blahblah". From a medical standpoint I'm certain that it's a no-issue. But what about camera gear? I guess I might not want to use wireless triggers there but anything else at risk?

Thanks

I drove up to Mt. Wilson, they have tons of transmitting towers up there. Got out walked around a bit. Went back to the car and used the clicker to try to unlock it, click, click, click, nothing! Even from 1" away NOTHING! Thank god it wasn't one of those cars that has no physical key mechanism or I would've be shafted. And it did make you wonder what was beaming on you up there. I've never had a key clicker fail to open something from a few feet away never mind still failing at just 1-2" inches away!
I assume it worked later...

If you are near a powerful source of rf it can overload the front end of the car's receiver, everything gets clipped and nothing gets decoded. I work 19 kilometers away from a transmitter tower which blasts out 30 megawatts of tv, fm radio, and various emergency transmitters. We need to put filters on all of our hf band receivers or all we get is AM 1200, no matter where it is tuned, if the antenna is rotated anywhere near the tower