[LINK] 5G not safe?
Gerard.Borg at anu.edu.au
Sat Apr 6 09:50:36 AEDT 2019
Hello David et. al.
You are correct for R.M.S (root mean square electric field) which is the
usual way to express
(R.M.S. Electric Field) = (Peak Electric Field) / sqrt(2)
My calculations follow.
Relation of power density to electric field strength (assume R.M.S
electric field) is as you say
(ELECTRIC_FIELD_STRENGTH__VOLTS_PER_METER)^2 / (120 * pi)
ELECTRIC_FIELD_STRENGTH__VOLTS_PER_METER = 9 R.M.S.
POWER_DENSITY__WATTS_PER_SQMETER = 0.215
We can also compute a hard exposure limit.
Consider RF transmission with 4Watt EIRP (Equivalent Isotropic Radiated
This would apply to WiFi using 2.5GHz or 5GHz and the legal emission limit.
Then the following calculation yields the maximum received upper power
density for any
type of antenna,
POWER_DENSITY__WATTS_PER_SQMETER = TRANSMIT_EIRP__WATTS / (4 * pi *
DISTANCE__METERS = 1
TRANSMIT_EIRP__WATTS = 4
POWER_DENSITY__WATTS_PER_SQMETER = 0.318
ELECTRIC_FIELD_STRENGTH__VOLTS_PER_METER = 10.9 R.M.S.
Having said this, actual human safety limits depend on RF carrier frequency.
5G power limits will have to comply with emission standards regardless
of what antenna(s) they use.
I do not believe that this will necessarily be difficult, even if base
stations have many antennas.
As an example from 5G, consider massive MIMO - a widely studied
technology which employs hundreds of
co-located, spectrum sharing antennas on a base station. The obvious
reason for this approach is to
improve spectral efficiency by sharing the radio spectrum simultaneously
with many mobiles. This has
led to demonstrations of spectral efficiences > 70 bits-per-second-per-Hz.
Massive MIMO also has the desirable side-effect of reducing the total
power transmitted from base
stations and mobiles compared to conventional single antenna systems
under otherwise the same conditions.
On 4/5/19 4:41 PM, Marghanita da Cruz wrote:
> Here is ACMA on the subject
>> Also, the closer a small cell is to your mobile, the less power it
>> needs to communicate. The new 5G base stations will go into â€˜sleep
>> modeâ€™ when there are no active users, making their power output
>> levels even lower than current 4G base stations.
> On 3/4/19 8:09 pm, David wrote:
>> On Wednesday, 3 April 2019 17:59:16 AEDT Stephen Rapley wrote:
>>> While the health impacts of RF exposure are real a quick survey of
>>> the source of this story and the host siteâ€™s other offerings -
>>> David Icke and anti-vaxer sentiments - leaves you with the sense
>>> this site is trying to squeeze the health concerns about 5G and RF
>>> in general into a tinfoil hat that doesnâ€™t do the issue justice.
>> Yes indeed. Linkers may remember a discussion some years ago
>> regarding a desk study by the epidemiologist Dr. Bruce Hocking for
>> Telstra which found a doubling of childhood leukemia in the suburbs
>> around Gore Hill in Sydney. This was to be phase-1 of a more
>> detailed study, but I understand Telstra cancelled phase-2.
>> The opening paragraph of the website item -
>> - states "Ms. Fremault accurately identified that a *5G pilot project
>> is not compatible with Belgian radiation safety standards* (9 V/m, or
>> 95 mW/m2 according to this online converter)".
>> But I believe the power density of an EM field of 'e' volts/metre in
>> free space is given by (e^2)/(120*Pi) watts/sq.metre. A field of 9
>> volts/metre is then 0.215 watts/sq.metre or 215 mW/sq.metre, not 95.
>> An ABC source once told me that the field on the roof of their
>> administration building at Gore Hill was around 5 volts/metre, and I
>> think that also used to be the Russian standard for maximum weekday
>> So I think the story is wrong somewhere (maybe me?)....
>> David L.
>>  https://www.powerwatch.org.uk/science/unitconversion.asp
>> Link mailing list
>> Link at mailman.anu.edu.au
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