Subject: How truly complicated is the BLUE WORLD (Philips).
Date: Wed, 22 Nov 2000 103659 -0600
From: Roy Beavers
To: guru
--------------------------------------------------
........Response from EMF-L.......
.........More from our techincal experts about the "double exposure"
question....
Previously I said that I was cutting off this discussion to keep it
separate in the "engineers" circle.... But Alasdair's response
below -- with all the earlier messages extended below -- provide too
good an opportunity to make an importanmt point which I believe we
ALL need to GRASP (at least) -- even if we don't fully understand....
What you can see in this discussion is: (1) How INTERACTIVE is the
Blue World, (2) How SYNERGISTIC (reinforcing) it may be, and (3)
How difficult it is too reach USEABLE conclusions about the EMF risk
in your locale merely by considering that ONE new power line or cell
tower that is suddenly appearing in your neighborhood......
If you talk and think that way (or if you allow the company reps to
talk that way)-- you are very likely FAR underestimating the true
consequences of the latest EMF/EMR addition into your local environment.
It is time for the "activists" to GET SMART about this aspect!!!
Think and measure and **litigate** IN TERMS OF THE TOTAL BLUE WORLD
consequences -- including, in particular, the FUTURE additions that
the telecom company will likely be adding to that tower (or the FUTURE
power requirements which are likely to increase the current on that
power line)....!!!
The discussion below gets right to the heart of this matter in a very
(too) technical way..... But it is important for everybody (including
your lawyer and local politicians) to fully understand......
Also, please go and read again guru's "Open Letter to the Commissioners
of Jefferson County, Colorado." It speaks to this very aspect -- in
layman's terms..... (Linked on the home page of my website.....
Down near the bottom)...... As is written there: the REAL QUESTION
ought always to be **What are we opening the door to??? In terms of
future (additive or synergistic) exposures.**......guru.....
(Thanks, again, Alasdair, Neil Cherry, et al.....)
-------- Original Message --------
Subject: Double exposure (Lei.t)(Ch.ry)(Curry)(Kane)
Date: Tue, 21 Nov 2000 22:21:05
From: Alasdair Philips
To: roy@emfguru.com, guru
CC: "Bill P. Curry" , "robert c. kane"
,"neil.cherry@crc.govt.nz" ,"Bruce Leifheit"
I am trying not to respond much at present, however......
I have inserted Bill Curry's long piece in this email as it contains much
wisdom and sets out some reasons why these issues are so complicated.
Robert Kane is correct in terms of how it is normally done. Measure all
the signals, peak over 6 minutes is usual, using a spectrum analyser. Then
take the square-root of the sum of squares of all the individual signals
in terms of Electric field, then translate that sq.root number back into
a power density using Neil's S=E^2/3.77. Neil was wrong with his
simple addition, though. Signals do not add like that unless they are
the same frequency and phase from the same place ~ ie unless you
effectively just turn up the power level of the output amplifier.
This is a fudge, but actually usually gives a fairly accurate estimate
of overall power level.
However, signal levels near a cellular mast (say 100 metres away)
usually vary ENORMOUSLY due to reflections, etc and can easily change
by a factor of about 3 (E-field) or 9 (power) within a few centimetres
(say 5 to 20 cms). These peaks will be at different places for each
frequency and so it is a pretty pointless exercise trying to determine
the total power in an area the size of a house (for example).
It is also complicated by many modern cellular signals being phase encoded.
It can also be complicated in the ways Bill sets out. (I do intend to respond
to him sometime when I get the time ~ it is a good piece, though!)
Also, we must remember that mostly we are not concerned with power levels
but with signal levels. The music from a CD does not come off in terms of
power. The laser light shone to it and reflected off it has virtually no
power in it, but it enables the CD player to detect the music signal and
play it to us at many hundreds of watts if we want. Living systems also
contain amplifiers and are non-linear, which is why most of us are more
concerned about non-thermal (ie not power) effects.
If you take Ted Litovitz's work (Catholic Uni, Washington), he shows that
a single ELF pulsing mobile phone can have dramtic adverse effects on living
systems, but if you ADD similar levels of extra noise with pseudo-random
timing, the adverse biological effects disappear! So, more MAY (just may!)
be better in some circumstances! Aaaargh.
It is essential, in my opinion, not to get too caught up with the power
question. If you look at ionsing radiation damage to living cells in a
living being, then there is a sharp high peak of damage at very low levels
of radiation exposure, then protective responses kick in and the effective
damage goes back almost to zero, when it then starts to rise slowly with
exposure in a typical dose response curve. We ignore that very low level
high damage peak at our peril. I suspect that it is similar with digital
microwave and ELF regularly pulsing EMF signals. We have one response at
the power end of the curve, and that is probably protected against fairly
well by the highish ICNIRP guidance levels. What we have yet to determine
are the details of the low level window effects.
That's my cents worth!
Good wishes, as ever,
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Alasdair Philips, BSc(Eng), DAgE, MIAgE
Director, UK Powerwatch, (aphilips@gn.apc.org)
EMC Engineer and EMF-bioeffects researcher
http://www.powerwatch.org.uk
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
At 10:58 21/11/2000 -0600, Roy Beavers wrote:
>........Another response from EMF-L on this item.....
>We seem to have discovered another electronics engineer!!! Good!!
>.....guru.....
>-------- Original Message --------
>Subject: Re: Double exposure (Leifheit)(Cherry).....
>Date: Tue, 21 Nov 2000 09:58:57 -0800
>From: "robert c. kane"
>Reply-To: rkane@tds.net
>To: roy@emfguru.com
>References: <3A18D8FE.59AB1C8E@emfguru.com>
>
>Physically it doesn't work quite that way. True, if the field intensity
>doubles the energy density increases by a factor of four, but adding a
>second radiator/antenna will not cause the field intensity to double.
>
>Of concern for a real situation are:
> 1) Phase coherence
> 2) Source frequencies (and each antenna transmits on many
>frequencies/channels simultaneously)
> 3) Mutual coupling of antennas
> 4) Directivity
> 5) Orientation
> 6) Configuration
> 7) Energy source type (i.e independent current source?)
>
>The question is ill posed because it does not define many necessary
>parameters for an adequate solution.
>
>Fundamentally, we might say that since energy is conservative, you won't
>get four times the energy at a measurement point by doubling the energy
>output at the sources. Better to take the square root of the sum of the
>squares approach for both E and H field intensities.
>
I forward this extremely technical item only to ensure that our techies
get it and get a chance to participate..... Please continue this
discussion direct within the technical community and off-line of EMF-L....
....guru.....
-------- Original Message --------
Subject: Re: Double exposure (Leifheit)(Cherry).
Date: Mon, 20 Nov 2000 12:33:50 -0600
From: "Bill P. Curry"
To: roy@emfguru.com
References: <3A18D7D4.B318F8A@emfguru.com>
Roy and Neil,
I think the usual practice is to add antennas that are far enough apart
not to be in each other's near field. Otherwise, the frequencies of the
resultant radiation would be the sum of the primary frequencies of the two
separate RF sources and the difference of these two frequencies. This would
not be good practice for communications links. Putting two RF sources at a
spacing of several wavelengths (of the lowest frequency source) will generally
avoid this problem and allow the intensity (radiation density) of the two
sources to be added linearly, instead of adding the fields.
My concern is whether, in the presence of a ubiquitous low frequency field
(wavelength longer than the RF tower height) might not allow the RF power
density to be magnified, because of the addition of the RF electric field to
the low frequency field. If the frequency of the low frequency field is
sufficiently low, the sum and difference frequencies of the resultants field
will differ negligibly from the original RF frequencies, so the human body
will perceive the resultant radiation to be the original RF radiation, but at
an enhanced radiation density - provided the strength of the low frequency
field exceeds the strength of the original RF field.
The paper that I delivered in Salzburg last June at the International
Conference on Cell Tower siting considered this problem, using a formulation
due to A. Sommerfeld (1925) for the mathematical description of the ground
wave from a low frequency AM broadcast source whose wavelength was
sufficiently large to submerge both terrain variations and the microwave
sources on the cell phone tower under consideration.
The significance of the ground wave is the fact
that it dies off with distance more slowly than the conventional sky wave
radiation from a point source, and it has the same polarization as the field
from a cell tower antenna. This means that the electric fields of the low
frequency ground wave and the microwave source are pointed in the same
direction; hence, the fields may then be added linearly, and the resultant
radiation density will be proportional to the product of the low frequency
field strength and the microwave field strength.
The key to this amplifying
mechanism is the requirement that the low frequency source must be stronger at
the location of interest than the microwave field. This is why I chose to
consider the low frequency source to have so low a frequency as to produce a
substantial ground wave. I would expect a similar amplification, however,
when a cell phone antenna is hung on a broadcast tower - AM, FM, or TV -
provided only that the electric fields have to be parallel to the field of the
low frequency source.
I invite your comments about this mechanism of amplifying RF radiation.
>
>Roy Beavers wrote:
>>
>> .........Response from Dr. Cherry......
>>
>> He says the double exposure calculation is off by half.... i.e., It
>> SHOULD BE FOUR TIMES!!!..... He's probably right.... Any more argument?
>> Clas, Alasdair, Bill, et. al.........guru......
>> (Now, consider what happens when the NEXT pair of antennae are added???)
>>
>> -------- Original Message --------
>> Subject: RE: Double exposure (Leifheit).
>> Date: Mon, 20 Nov 2000 20:22:19 +1300
>> From: Neil Cherry
>> Reply-To: "neil.cherry@crc.govt.nz"
>> Organization: Canterbury Regional Council
>> To: "'roy@emfguru.com'"
>>
>> Dear Roy,
>>
>> As we know the power density (microwatts/sq cm) is a function of the square
>> of the electric field (S = E^2/3.77) where E is the electric field in V/m.
>> i.e. E = 10 V/m converts to S = 100/3.77 = 26.5 microwatts/sq cm. I
>> understand that the fields are additive. This would mean that rather than
>> adding two equal signals of 26.5 microwatts/sq cm (giving 53 microwatts/sq
>> cm) instead we add the two E fields, i.e. 10 + 10 = 20 V/m. This then
>> becomes S = 400/3.77 = 106.1 microwatts/sq cm (4 times the power density).
>>
>> Can any of our engineering experts confirm or correct this ?
>>
>> Regards
>> Neil Cherry
>>
>> -----Original Message-----
>> From: Roy Beavers [SMTP:guru@emfguru.com]
>> Sent: Sunday, 19 November 2000 21:08
>> To: guru
>> Subject: Double exposure (Leifheit).
>>
>> ............From EMF-L........
>>
>> Yes, it very likely will double the exposure (approximately)..... P.S.
>> There will likely
>> be MORE to follow........
>>
>> That is probably the REAL problem with these towers -- not the first
>> lonely antenna
>> that is mounted..... But those that follow....... Is that right,
>> Sutro Tower????.....guru....
>>
>> -------- Original Message --------
>>
>> Subject: cell tower emf
>> Date: Sat, 18 Nov 2000 16:52:33 -0500
>> From: "Bruce Leifheit"
>> To:
>>
>> DEAR ROY, SPRINT PCS ERECTED A CELL TOWER IN 1998 LESS THAN 100' FROM
>> MY HOME. WE TRIED IN VAIN TO HAVE IT STOPPEDBUT AS I WRITE THIS IT IS
>> STILL IN APPEAL. I WAS WONDERING IF YOU COULD SHED SOME LIGHT IN LAYMENS
>> TERMSABOUT POSSIBLE HEALTH EFFECTS THIS COULD HAVE UPON MY WIFE ,KIDS
>> AND I.ALSO AS I WRITE THIS THEY AREADDING A SECOND SET OF ANTENNA AND
>> ALL NESCESARY HARDWARE TO PROVIDE FOR A SECOND CARRIER. DOES THIS DOUBLE
>> MY FAMILIES EXPOSURE AND RISK. ANY INFORMATION YOU COULD PROVIDE WOULD
>> BE GREATLY APPRECIATED.
>> SINCERLY
>> BRUCE LEIFHEIT
>> 3928 STATE ROUTE 225
>> DIAMOND, OHIO 44412
>> 330-654-3492
>> << File: ATT00004.html >>
>
>
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Alasdair Philips, BSc(Eng), DAgE, MIAgE
Director, UK Powerwatch, (aphilips@gn.apc.org)
EMC Engineer and EMF-bioeffects researcher
http://www.powerwatch.org.uk
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Archive provided courtesy of WaveGuide, http://www.wave-guide.org
Reprinted with permission of Roy Beavers, http://www.emfguru.com