Cellular Phone:
Cell Phones & Shields


20 April 2000

---------- Forwarded message ----------
Date: Thu, 6 Apr 2000 06:35:38 -0500 (CDT)
From: "Roy L. Beavers" <rbeavers@llion.org>
To: emfguru <rbeavers@llion.org>
Subject: The "science" of Cell Phones & shields (Hess)(Curry)..

.......The "science" of cell phone exposure is not terribly advanced.  It has been left up to the cell phone industry -- and they are in NO HURRY to have that science advanced......!!!

But (physicist) Dr. Bill Curry has been looking into it...... (See below).....

Roy Beavers (EMFguru)

It is better to light a single candle than to curse the darkness

People are more important than profits!!

---------- Forwarded message ----------
Date: Wed, 05 Apr 2000 23:37:30 -0500
From: "Bill P. Curry" <BPCurry@MCS.com>
To: "Roy L. Beavers" <rbeavers@llion.org>
Subject: Re: Phones & shields (Hess).. (fwd)

Roy and Paul,

The basic problem with all the cell phones with which I am acquainted is that the antenna feed region occurs near the earpiece or other vulnerable areas.   Motorolla's newest phones produce fairly low SAR values, because in the tests the antenna points out at an angle from the simulated head. What I don't know is how well the tests simulate the interaction of the microwave antennas and their driving circuits with the human head.  In reality, the head, being slightly electrically conductive, partly short circuits the phone antenna system.  This means some of the energy that is normally stored in the electric and (mostly) magnetic fields of the antenna is drained into the head.

This causes the resonant circuit characteristics of that system to change. Now, the antenna feed line impedance no longer matches well into the antenna, resulting in partial blockage of waves moving out onto the antenna and standing waves existing at the feed point.  Unless the design of the antenna takes into consideration the way the head loads the antenna, there will be more radiation through the earpiece than through the antenna.  In addition, there is some radiation leakage through the mouthpiece and the key pad.  I have measured the radiation from these different areas, being careful not to put the meter probe so close to the phone as to seriously disturb the readings and allowing for self consistency checks in making the measurements.

I have also measured the effectiveness of the PhoneShield (TM) on our old analog phone, a Motorola Microtac.  By my measurements this shield cuts out 97.5% of the radiation that would otherwise come through the earpiece. I think there are several brands on the market that probably use the same technology, so I am not endorsing one shield against another for the old analog technology phones.

I have been told that the same technology (use of absorbing and possibly reflecting layers of fibers) does not work well on the newer pulsed digital phones, but I haven't tested this proposition yet. Incidentally, the CDMA technology is supposed to smooth the phone response, becuase its pulses are quasi-random.  When I measure output from such a phone (in conversation) I get a very low average level, but when I look at the pulses, I get fairly high levels - on the order of 27 microwatts per square centimeter when measuring output of a phone that was in use diagonally across a train aisle from me.

With CDMA phones, by the way, if you don't talk you won't get any measureable output.  The phone logic is designed to prevent silent transmissions.

I am sorry that you can't get any more helpful information about which phones are categorically safe, because no phones have been scientifically proven to be safe.  Unfortunately, since there is no conclusive proof that any phone is unsafe, the industry makes the fallacious leap of logic and assumes they are safe.  The government doesn't protect us against the false assurances of the industry.  [.......!!!!!!......guru......]

It is up to the users to practice prudent avoidance.  It undoubtedly helps to have a long line between the phone and earpiece and mouthpiece, but that is still not a total solution.  If you hang the phone on your belt, you will still have the problem of the antenna and feed line interacting with human tissue - not brain tissue, but gonads, kidneys, etc.

Bill Curry, Ph.D. (Electricity/physics).....

Roy L. Beavers wrote:

.........An angry/concerned response......

...........From EMF-L........

---------- Forwarded message ----------
Date: Wed, 05 Apr 2000 18:09:24 -0700
From: Paul Hess <pchess@jps.net>
To: "Roy L. Beavers" <rbeavers@llion.org>
Subject: Re: Phones & shields (Hess)..

Well Roy, you seem most interested in the politics of EMFs and convincing us to go without them.  But has it occurred to you that some jobs require these things? Will somebody please say all the shield products are useless and all their tests just lies so that I can forget about it, or indicate which products might be the most helpful.


At 05:32 PM 4/5/00 -0500, you wrote:

........That's about right, Paul, if the EMF science were as exact as people want it to be (and expect it to be) ... , then it would be a lot easier to get the government to do its job -- namely:  to stop protecting the industry while passing the "risk" to the people.....

Has it occurred to you ... that it just may be ... that there is NO "safe" cell phone......???  At least not with the present state of the knowledge about the EMF/EMR bioeffects......!!!


Roy Beavers (EMFguru)

---------- Forwarded message ----------
Date: Wed, 05 Apr 2000 14:12:43 -0700
From: Paul Hess <pchess@jps.net>
To: rbeavers@llion.org
Subject: phones& shields

Thank you for your responses. Many of the websites I visited are still inconclusive.

It seems like there is no reliable way to evaluate phones. The SAR test result is not consistent with reports that its lowest EMF phone, the Motorola, has a reputation with customer complaints about symptoms.

It also seems to be implicit in most responses that shields do not work. True? It seems this is the last hope.


Bill P. Curry, Ph.D.     |Physics is fun.
EMSciTek Consulting Co.  |Trying to make a living!
22W101 McCarron Road,    |Phone: (630) 858-9377
Glen Ellyn, IL 60137     |Fax: (630) 858-9159 with prior notice

Back to Top