Mobile Telephone Electromagnetic Energy Exposure - Page 1
Forum section: electronics / general

author: Halcyon
author_rank: Unknown
timestamp: July 15, 2015, 11:27:50 am
content: I received the attached SMS from my mobile carrier today and thought to myself "what a load". I get these every few months. I've never worried about exposure to mobile phone radiation, in fact, when looking for a new phone, I want one with the highest gain antenna and highest SAR rating I can get to ensure sustained coverage in rural areas.I'm sure there are plenty of other things in this world that'll kill me well before using a mobile phone will.I know a thing or two about electronics and in my opinion, this is a very old argument that refuses to die. What are your thoughts?(By the way, my handset and carrier mostly use 700MHz, 850MHz, 2100MHz and 2600MHz bands.)UPDATE: I tried using their 24/7 online chat service to opt-out of these SMS's. Two "consultants" and over 30 minutes later and they still had no idea. They eventually just referred me to their 1800 number during regular business hours.

author: tautech
author_rank: Super Contributor
timestamp: July 15, 2015, 11:41:39 am
content: Typical corporate trying to keep its arse covered.I'm with you, its an old load of

author: Halcyon
author_rank: Unknown
timestamp: July 15, 2015, 12:00:14 pm
content: Quote from: wilfred on July 15, 2015, 11:58:39 amI'm not a particularly heavy user and I've only started getting these since I re-contracted onto their new plans earlier this year (for the same price per month, I now get 10GB of data and unlimited calls, SMS, MMS... as opposed to 3GB of data before).

author: TimFox
author_rank: Super Contributor
timestamp: July 15, 2015, 02:24:15 pm
content: Technical note:If you are very close to the antenna, you are not getting EMradiation.Instead, you are in the "near field", where energy is stored to produce the radiation downrange in the "far field".The relationship between the "near field" field strength (in V/m) and the "far field" radiation (in W/m^2) depends on the details of the antenna design and other fields from the transmitter circuitry nearby.At these frequencies, most of the real data I have seen are for "far field" radiation, which is relevant to victims standing near a cell antenna tower (several wavelengths away), but not directly relevant to holding the source against your head.

author: amyk
author_rank: Super Contributor
timestamp: July 15, 2015, 03:57:18 pm
content: You get a stronger dose of EM radiation from the Sun on a good day than any mobile phone...Things like this always remind me of this story:http://mybroadband.co.za/news/wireless/11099-massive-revelation-in-iburst-tower-battle.html

author: IanB
author_rank: Super Contributor
timestamp: July 15, 2015, 04:42:34 pm
content: Cell phone antennas radiate energy at a power level sufficient to be received by a cell phone tower a mile or more away. Consider the inverse square law of radiated power and then put the phone right next to your ear. How much radiated power is potentially absorbed by your brain? The thermochemical and electrochemical effects of this on the delicate biological systems of the brain are not completely understood, so it is reasonable to be cautious and to limit exposure.I have also read that using a wired earpiece can direct and focus energy from the phone directly into your ear. So maybe it is better to use a Bluetooth headset or to use the phone in speaker mode (as I always do)?

author: Ian.M
author_rank: Super Contributor
timestamp: July 15, 2015, 05:20:37 pm
content: A bluetooth headset is itself a RF transmitter.Running the wired headset lead through a EMI suppression ferrite would do a lot to mitigate any reradiation from the lead.However, if you are concerned about exposure, use speakerphone mode with the phone on the desk!

author: RickBrant
author_rank: Unknown
timestamp: July 15, 2015, 05:46:43 pm
content: Quote from: IanB on July 15, 2015, 04:42:34 pmGetting 700 MHz or higher through a one meter or so headset cable? It would basically be shorted out by the cable capacitance long before it reached your head.

author: TimFox
author_rank: Super Contributor
timestamp: July 15, 2015, 06:37:02 pm
content: Quote from: IanB on July 15, 2015, 04:42:34 pmWith the phone right next to your ear, you are in the near field region and the inverse square law is no longer valid.

author: RickBrant
author_rank: Unknown
timestamp: July 15, 2015, 09:49:39 pm
content: Quote from: Ian.M on July 15, 2015, 05:20:37 pmBut of FAR lower power than the phone.

author: Mechanical Menace
author_rank: Super Contributor
timestamp: July 16, 2015, 01:22:27 am
content: Microwaves, no matter the power, are still non-ionising radiation yes? So if they aren't strong enough to cook you it's not going to effect a single atom in your body more than some dim light will or am I missing something?

author: Tinkerer
author_rank: Frequent Contributor
timestamp: July 16, 2015, 03:44:42 am
content: I did research on this back in college. At worst, there is an increase in risk, or instances I suppose, of something on the order of .5-1% maximum in cancer. In otherwords the benefits have far far outweighed the worst risk.

author: richard.cs
author_rank: Super Contributor
timestamp: July 16, 2015, 09:49:21 am
content: Quote from: Mechanical Menace on July 16, 2015, 01:22:27 amThis is my understanding also, the only possible effect within known physics is thermal. This is why microwaves (at higher levels than from phones) are dangerous to the lens of the eye and similar tissues which have neither circulation for cooling nor nerves to detect heat.

author: IanB
author_rank: Super Contributor
timestamp: July 16, 2015, 02:47:00 pm
content: Quote from: richard.cs on July 16, 2015, 09:49:21 amKnown physics also believes that electromagnetic waves induce voltages and currents in the receiving apparatus. Are you confident that inducing voltage gradients inside your brain where there are many sensitive electrochemical pathways and ion/membrane interfaces is entirely without risk?

author: RickBrant
author_rank: Unknown
timestamp: July 16, 2015, 04:25:16 pm
content: Quote from: IanB on July 16, 2015, 02:47:00 pmIn repeated experiments, as well as inadvertent exposure cases, at much higher power levels, there has been no evidence of such risk. The large mass of wet tissues that make up the brain make a completely lousy receiving antenna at ANY wavelength. So the EM waves, rather than inducing currents, tend very strongly to turn into heat.