Slashdot Mirror
Killer Apartment Vs. Persistent Microwave Exposure?
An anonymous reader writes "I am considering buying a penthouse apartment in Manhattan that happens to be about twenty feet away from a pair of panel antennas belonging to a major cellular carrier. The antennas are on roughly the same plane as the apartment and point in its direction. I have sifted through a lot of information online about cell towers, most of which suggest that the radiation they emit is low-level and benign. Most of this information, however, seems to concern ground-level exposure at non-regular intervals. My question to Slashdot is: should the prospect of persistent exposure to microwave radiation from this pair of antennas sitting twenty feet from where I rest my head worry me? Am I just being a jackass? Can I, perhaps, line the walls of the place with a tight metal mesh and thereby deflect the radiation? My background is in computer engineering — I am not particularly knowledgeable about the physics of devices such as these. Please help me make an enlightened decision."
If you're that close, you should be able to put a small coil of wire in your apartment and induce a nice free electric current. It won't make you popular with the owners of the antenna but what do they know? Otherwise no, I don't see a problem with RF.
Tubby or not tubby. Fat is the question
The FCC enforces on a case-by-case basis. Unless someone has turned this situation (this SPECIFIC apartment being this close to a transmitting antenna) to the FCC, then chances are that they have no idea the situation even exists. As for my $0.02, you don't want to spend any more time than you have to being 20 feet from a transmitting antenna, LET ALONE living next to one.
Are there any laws against passive shielding inside your flat? After all, you could simply put standard metal office furniture inside your flat, and that would cause massive interference, too. I'd say, if the phone company doesn't want the signal to be blocked by whatever is inside a flat, it should put the tower somewhere where it won't be blocked by something inside a flat.
The Tao of math: The numbers you can count are not the real numbers.
The FCC may have something to say about that though. If he is close enough, his mesh may block enough of the signal to put the antenna out of use.
Any passive blocking that he puts on the walls or windows as an owner is something that he can't he held liable for(as opposed to active blocking or putting up a billboard or similar). I'd love to see the judge's face when the cell phone company tries to explain how their antenna requires his apartment to be non-shielded to operate properly(ie - we need to beam the signal *through* it because we put it in a bad location). They are supposed to be placed in such a manner that they are clear of buildings and physical obstructions. Hence the reason they are almost always on a small tower above a roof top. One thing, though - if you shield your place from these frequencies, you won't be able to use your cell phone at all while at home. You *can* turn your house into a giant Faraday cage. But expect it to act like one as well. You likely also won't be able to use your radio or HDTV over the air. Nothing comes in means nothing gets out as well. (OTOH, Wi-fi in home would be secure - heh)
Also, the refit won't be cheap. That Scotchtint runs about $1000 for a 60"x100ft roll. EMI resistant mesh for the walls generally runs the same. Generally you have to re-plaster or put another thin layer of drywall over top of it, which is factored into that price. And of course, it has to be installed properly. At that range(feet vs hundreds of feet) it will generate a significant amount of current.
Possible? Of course. But in today's world, being without tv, radio, wireless, and so on in such a place in NYC would be horrendous. In fact, trying to sell a place that you purposely turned into that would probably make it just as hard to resell as if you did nothing at all. I'd just keep looking. Maybe there's a similar place a block or two over?
You tried your best, but missed the relevant points, sorry to say:
The inverse-square actually depends on the directivity of the whole lot. A point source is fine, a laser isn't.
Therefore, the 'proximity' isn't good neither. Roughly, considering your side of the head to be flat and the phone a point on that plane, you get half of the energy into your brain. That's not convincing, to me, because that's easily half a watt of RF that seeps through my brains. If I put my phone 20 feet away (let's stick to scientific units: 6 m), the point source would seep around 1 watt through a surface of a sphere 4*pi*r*r, that is around 100 square meters. With the average head diameter being around 22 cm, the surface of the head through which the energy seeps is around pi*r*r, that is around 0.04 square meter. So you'd get around 1/100*0.04, that is 0.0004 watt of RF radiation. That wouldn't bug me at all.
But I wouldn't buy the place nevertheless: Firstly, you don't know the actual RF-wattage as produced. It can be significantly above 1 watt. How about 100 watt? And then, you don't know the directivity of that antenna. If it focuses the energy into your direction, and the main beam has a diameter of 1 m at 6 m of distance, it would blow 4 watt through your brain, and that 24/7. A parabola antenna is very good at concentrating energy. The place is not good at all. Fingers off, it might be totally harmless (see above), and it might be bad for your health (see below). Better safe than sorry!
That's my advice!
Even though I'm skeptical that relatively low levels of microwave radiation could really be harmful, I thought I should point out that these metallic coatings or similar solutions do not absorb the radiation, they merely reflect it. Since complete coverage (floor, ceiling, windows, doors, etc) isn't realistic, you may easily reduce radiation overall but you might be allowing standing waves in certain locations, concentrating the radiation here and there, like hot spots in a microwave oven. An appartment is much bigger than a microwave oven, the walls are less flat, and there is more absorption etc. But the overall principle still applies to some degree. So I guess if I were worried enough about microwave radiation, still bought the apartment, but applied these reflective paints and such, then I'd also be worried about standing waves. Sniffing these out would be very time-consuming.