22 GHz is the resonant frequency of water folks. Not 2.45 GHz. uwave ovens heat by way of dielectric heating. Oils heat much faster than water. That's why your uwave food mfrs load up on the oils and salts in the food. Which by the way, hasn't been looked into as far as a high fat diet contributing to cancer. Or has it?
Also, the higher above 1GHz you go, the more surface heating of a human body happens. Not deeper. Deep tissue heating combined with surface tissue heating happens below that. Ionization of atoms and molecules require much higher freqs which translates to higher levels of eVs. Typical eV's that occur during normal chemical reactions with STP (standard temp and pressure) is about 15 eV. The photo-electric work function of say Tungsten = 4.58 eV = 2694 Angstroms = 0.000027 cm. Pretty damn small in my opinion. And you have to get far above approx 10 mW/cm^2 to really start being a problem. 1 mW/cm^2 I think is the limit. I worked the numbers out with one uwave oven which I thought had exceedingly high emissions, and it turned out to be pretty benign in terms of W/cm^2. More like uW/cm^2. Higher freqs are required to actually start perturbation at the atomic level. At the low GHz range, you're only perturbing the general molcular structure en masse. You have to go much higher to start doing the funky thing with an atom. Trying to consider that *only* uwave ovens are even involved with the whole cancer thing leaves out many many other factors to the point of being ignored. All the above of course, IMHO. And opinions may vary at any speed. Regards, Doug McKean > -----Original Message----- > From: [email protected] [mailto:[email protected]]On Behalf > Of Ken Javor > Sent: Friday, April 20, 2001 2:40 PM > To: [email protected] > Subject: 2. 4 GHz cordless telephone, question of general interest > > > > Someone on this forum likely knows the answer to this question... > > I was at Wal-Mart the other day and they had 2.4 GHz cordless phones on > clearance. My home cordless phones are 900 MHz. One is multiple > channels, > the other is some kind of spread spectrum. 2.4 GHz is very close to 2450 > MHz, the microwave oven frequency that resonates with H2O > molecules. Is 2.4 > GHz close enough to 2450 MHz to cause significantly more heating than 900 > MHz (in the human head adjacent to the head/handset antenna)? I realize > this is very low power relative to a cell phone, but I wonder if the issue > was ever addressed. Another way of asking this question is, what > is the "Q" > of H20 resonance? If it is much better than 50, the problem is not > important. If it is 50 or less, then 2.4 GHz would transfer more > energy to > head tissue than 900 MHz. One way of measuring this effect would > be to time > how long it takes to raise the temperature of a beaker of water a > set amount > at 2450 MHz, and then time how long it takes at 2400 MHz... > > But this all must have been done already... > > ------------------------------------------- > This message is from the IEEE EMC Society Product Safety > Technical Committee emc-pstc discussion list. > > Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ > > To cancel your subscription, send mail to: > [email protected] > with the single line: > unsubscribe emc-pstc > > For help, send mail to the list administrators: > Michael Garretson: [email protected] > Dave Heald [email protected] > > For policy questions, send mail to: > Richard Nute: [email protected] > Jim Bacher: [email protected] > > All emc-pstc postings are archived and searchable on the web at: > http://www.rcic.com/ click on "Virtual Conference Hall," > ------------------------------------------- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: [email protected] with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Michael Garretson: [email protected] Dave Heald [email protected] For policy questions, send mail to: Richard Nute: [email protected] Jim Bacher: [email protected] All emc-pstc postings are archived and searchable on the web at: http://www.rcic.com/ click on "Virtual Conference Hall,"
