Douglas A. Tutty wrote:
On Tue, Feb 05, 2008 at 11:58:28AM -0500, Christopher Judd wrote:PS FWIW, I doubt that it is really the high frequency fields that she is sensitive to, but without another explanation, you have to gowith what works for you. FYI, UHF TV signals are in the 70 - 1000 MHz range. It would be hard to escape these anywhere near civilization, although the signal strength may be quite low.I thought that the standard FM band (88.7 MHz - 108.?) sat between channels 6 & 7 on the TV VHF band. I suppose I could check wikipedia. The upper UHF TV channels go cut to make room for cell phones when they came in.
If you can find open spectrum in virtually anything DC-to-Daylight in the U.S., you're a LONG way from populated areas, or you're in the National Radio Quiet Zone.
http://en.wikipedia.org/wiki/United_States_National_Radio_Quiet_ZoneIt's why the regulatory agency (note: not a revenue generator for the government, the REGULATORS) can make $4+ billion auctioning off 30 MHz of spectrum. (And some of us are still wondering where that 4 billion goes, after the FCC runs these new-fangled spectrum auctions.)
There are not many open holes in this chart: http://www.ntia.doc.gov/osmhome/allochrt.pdf That's the real deal.There have been a lot of studies of people who claim "frequency sensitivity" and only one case where the person did seem to truly have some minor sensitivity to RF (I remember reading the article, but I can't find it now) at certain frequencies in scientific testing.
But, there were quite a few MORE people who were actually sensitive to ultra-sonic frequencies... audio that was above the normal range of human hearing.
Many of those people had reported that computers and electronics bothered them, and what was found was that they could HEAR these frequencies, in almost a subconscious way, and it would annoy them, distract them, etc.
A small and poorly done study published recently that they proved that some people sleep poorly in the presence of 800 MHz signals, but they didn't produce a very large sample and they didn't properly measure the field strengths needed.
This report immediately got spun into "GSM cell phones will cause you not to sleep", when of course, most GSM phones are NOT operating in the 800 MHz spectrum MOST of the time (they are on the higher alternate bands, unless they can't reach that network for some reason or another), and various other "reality check" problems with the stupid news reporting (and reporters who don't check sources and facts).
It's VERY easy to shield an area of a house or building to keep in or out certain frequency ranges. RF engineers do this all the time to create RF test chambers and other "quiet" areas for receiver testing, etc. (Faraday cage.)
I'd put money on the ultrasonics in her case, if she's really sensitive to electronics operating nearby. She can probably HEAR them running, and doesn't realize it because it wouldn't be real obvious... there is no training in your youth from family/friends "Hey, do you hear that?" for folks that have extended hearing ranges.
I can't hear ultrasonics, but I whiz through hearing tests up into very high frequencies and I hear things that my wife simply can't hear... I get into her car and say, "When did that noise start?! That sounds bad... we might need to get the X fixed!" and she wonders what the heck I'm talking about.
My father, and grandfather and supposedly great-grandfather also "suffered" from mild tinitis (ringing of the ears - for some people it never stops, and can literally drive people mad), but I've never dug to see if there's a real genetic link for that particular malady.
I've had episodes of mild ringing, but I understand this can simply be from damage to the cilia in the ear, and I'm pretty bad about listening to loud music, and I fly small aircraft (with hearing protection, but it's still bloody loud in a light aircraft, no matter how you slice it) and love anything that makes a hell of a lot of noise, like airshows, screaming crowds at events, etc.
This also explains why my wife thinks a $30 "boom box" is "fine" and wonders why I insist on buying quality stereo equipment and speakers anytime I can afford them. She honestly probably can't hear the difference, or not as much of one.
Nate