Hello David et. al. You are correct for R.M.S (root mean square electric field) which is the usual way to express averages.
(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 given by POWER_DENSITY__WATTS_PER_SQMETER = (ELECTRIC_FIELD_STRENGTH__VOLTS_PER_METER)^2 / (120 * pi) If... ELECTRIC_FIELD_STRENGTH__VOLTS_PER_METER = 9 R.M.S. then.. POWER_DENSITY__WATTS_PER_SQMETER = 0.215 We can also compute a hard exposure limit. Consider RF transmission with 4Watt EIRP (Equivalent Isotropic Radiated Power). This would apply to WiFi using 2.5GHz or 5GHz and the legal emission limit. https://www.legislation.gov.au/Details/F2014C00930/ff366b29-3c57-447d-a6e7-e15451eeee83 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^2) and for... DISTANCE__METERS = 1 TRANSMIT_EIRP__WATTS = 4 we obtain... 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. Gerard 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 ‘sleep >> mode’ when there are no active users, making their power output >> levels even lower than current 4G base stations. > > https://www.acma.gov.au/Home/theACMA/a-guide-to-small-cells?utm_medium=email&utm_campaign=Engage+Issue+85+February+2019&utm_content=Engage+Issue+85+February+2019+CID_0998af901bd146f29999a70232559280&utm_source=SendEmailCampaigns&utm_term=small+cells+fact+sheet > > > > 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 site’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 doesn’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 - >> https://takebackyourpower.net/brussels-first-major-city-to-halt-5g-due-to-health-effects/ >> >> - 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[1])". >> >> 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 >> exposure. >> >> So I think the story is wrong somewhere (maybe me?).... >> >> David L. >> >> >> -------- >> [1] https://www.powerwatch.org.uk/science/unitconversion.asp >> _______________________________________________ >> Link mailing list >> [email protected] >> http://mailman.anu.edu.au/mailman/listinfo/link > _______________________________________________ Link mailing list [email protected] http://mailman.anu.edu.au/mailman/listinfo/link
