So, are they dangerous or is it just an idea spread by nimbys? How far away from a mobile mast would you want to be?

no.

the radiation (whether you believe it’s dangerous or not) comes from your phone. the further from the mast you are, the more radiation is emitted by a phone. the closer you are, the less radiation there is.

there’s a lot of shit information out there from people who simply don’t understand physics/electronics, and who can’t be bothered to actually study it

Tom (son of a professor of radio electronics, who spent his career studying and developing mobile phone networks)

Cheers. The one we’re looking at is near a primary school so thought it wouldn’t be that bad.

Given the high voltage cables that are burried in most streets, should people be as concerned about them or is it simply a case of out of sight, out of mind.

I’ve built them, repaired them, and am currently surveying them for upgrades all day…
No adverse issues yet.
Like Tom says, the closer you are the better..

where are you going?

Never mind about mobile phone masts or high voltage cables, it’s chemtrails that you want to worry about. Mark my words.

Pook, looking at eckington at the moment. But always open to advice.

Same as teetoosugars have worked in mobile comms for 13 years and no ill-effects, working from the base station to the top of the towers! Who and what are you working on/for just now teetoo?

No, not chemtrails, it’s infrasound! Bloody wind turbines with their infrasound!

(We have a local fanatic on one of the village councils who is never short of finding a drum to bang about something)

Did you hear that ?

Who and what are you working on/for just now teetoo?

Set off on my own, currently on the NSN side of the CTIL L800 Beacon/ Metropolis project.
That and EE’s Darwin one.

Good move, you doing work for Clarkes by any chance? I moved to BT MSL last year best move ever!

You are safe. My PhD was in antenna design and electromagnetic wave interaction with the human body for mobile communication applications so I can confidently say that at the powers and antenna gains used in base stations the safe working distance is around a metre.

(We have a local fanatic on one of the village councils who is never short of finding a drum to bang about something)

My boss had one of those recently who claimed he could sense the flare going off. Eventually he went round to here house with a lawyer under the pretence of negotiating a settlement (££££). After the pleasantries they asked them if they’d been suffering much in the last couple of weeks? Yes apparently, right now in fact. So he skypes an operator who points his phone at the flare, which shows…………….no flare.

Slight diversion but can someone point me in the direction of EM radiation from a substation – something along the lines of “If you live 10m from a substation it’s no worse than sitting 2m from a TV” or similar?

jonm81 – is that 5mW/cm² ?

Onzadog – Member
Pook, looking at eckington at the moment.

The one near Sheffield or the one in Worcestershire?

hungry monkey – Member
no.

the radiation (whether you believe it’s dangerous or not) comes from your phone. the further from the mast you are, the more radiation is emitted by a phone. the closer you are, the less radiation there is.

A mobile phone is a 2 way radio. It has a receiver and a transmitter. so this is incorrect. However, your brain is much closer to one than the other.

Now then, what about wireless charging points…next to your bed?

Ned, the Sheffield/ NE Derbyshire one.

Ah. Wife’s from the other one!

I’d be more worried about having a baby monitor.. They kick out huge amounts of power.

I’d be more worried about having a baby monitor.. They kick out huge amounts of power.

Ours kicked out enough crap to fool the heating into being on all the time (whilst the monitor was on).

“Banging an Infrasound Drum” – I like that..very Zaphod Beebblebrox

the radiation (whether you believe it’s dangerous or not) comes from your phone. the further from the mast you are, the more radiation is emitted by a phone. the closer you are, the less radiation there is.

Err, no.

As said before mobile phones are 2 way, so the Base station transmit and your phone transmit. However, the duty cycle of the base station will be much higher (100% when busy), whereas your phone only transmits periodically when you’re not making a call, so the duty cycle is tiny eg 0.01%. A mobile phone base station also transmit more power than a handset eg 40W vs maybe 2W for a handset.

Now some maths…

Let’s assume you’re 1m away from your handset, FSL for 1m @ 900 MHz = 31.5 dB

Let’s assume you’re 100m away from a base station, FSL for 100m @ 900 MHz = 71.5 dB

So, on the face of it the power from the Base Station is 40 dB less (10,000x). However, the duty cycle of a busy mast is at least 10,000x greater than that of a dormant handset, so the power over time will be the same.

A typical GSM BS is 40 Watts vs 2 Watts for a handset, so the BS is kicking out 20x the power of a handset.

So, in the case of 1m mobile vs 100m GSM mast, you’ll get more EM radiation from the mast when it’s busy by at least 20x, probably more.

NB As for your handset reducing power when it’s near the mast, this assumes that the mast near you is your provider, which is about a 1 in 4 chance.

This is where your argument falls down.

Your phone transmits intermittently to communicate with base towers, even if not calling. It’s probably in your pocket near you balls most of the time it’s doing this.

It’s mm from you brain when calling so that maths up there is bunk

When you are far from a station, your phone increases the receiver gain and the transmit power. If you are close with good line of sight, the phone’s transmitter output is minimized.

I would not worry about being close to a base station.

You also have to consider that the mast isn’t pumping out the signal in an omnidirectional fashion most likely it is using multiple directional antenna and only transmitting on the ones it needs to (plus an element of beam forming) In fact due to the height and the directional characteristics of the antenna being too close to the mast puts you outside of the optimum beam path from the antenna.

I’m sure it is something to do with Big Pharma. Must be.

I thought about mentioning this one earlier. The optimum place to be to minimise the signal from the mast is likely to be directly underneath it.

So ideally everyone should have a mobile phone mast on the roof of their homes ?

You also have to consider that the mast isn’t pumping out the signal in an omnidirectional fashion most likely it is using multiple directional antenna and only transmitting on the ones it needs to (plus an element of beam forming) In fact due to the height and the directional characteristics of the antenna being too close to the mast puts you outside of the optimum beam path from the antenna.

Most masts are either mono or tri-sectored. In towns the most common configuration is tri-sectored where you have three antennas 120 degrees apart, which give a petal like pattern, rather than uniform coverage; but even at the crossover points you’re probably only 6dB down on bore sight gain.

They have an elevation pattern, so there is a bit of a shadow immediately below them, but in central London it’s quite easy to be sat directly in the main beam across the road (less than 100m away).

Eg this is an O2 site on a hotel nr Russel Square, tri-sectored, pointing down off the roof right at the offices opposite:

[url=https://flic.kr/p/aJi2yM]Hotel Roof[/url] by Ben Freeman, on Flickr

So ideally everyone should have a mobile phone mast on the roof of their homes ?

Preferably with a concrete roof to act as a shield, antenna beam patterns at GSM frequenies roll off quite gently, so there is still reasonable power below a mast.

This is where your argument falls down.

All depends on where you keep your phone. I almost never have it in a pocket, it’s either on my desk at work or at home it sits on the kitchen table.

jonm81 – is that 5mW/cm² ?

Cant remember the exact value without looking it up but it was the worker exposure limit within the ICNIRP standards. The public limit is lower but with the pathloss at those frequencies it only added about 20cm to the safe working range.

Incidently, the heat build up within the head does not come from the radiation but from heat dissipation from the phone itself and the fact you are holding it to the head. Whilst the transmitter within the phone may be about a watt the antennas are only around 15-20% efficient meaning that the power lost is turned into heat further exacerbating the heating of the ear and head.

Ah used to work in Eckington. There are some nice man made trails in the woods to the NW of the Eckington. Think there are some DH type trails at Rother Valley as well but never got round to trying them.

Does frequency have an effect, just thinking all those people protesting mobile phone masts yet they don’t complain about WiFi in a school which is an eesential for little Chardonnay

Where do you keep it when you’re using it?

It does. Though the levels of power and the distances involved are also different (and in exactly the same way it’s the device which will irradiate you more than the base station as it’s a lot closer – of course a phone will typically be spewing out both phone and Wifi radiation 😯 ). I wouldn’t like to say which was more harmful, because realistically the answer is neither – and I suspect those who might complain about phone masts or even about wifi if they were sufficiently clued up to get worried about that are probably also the ones who will race up to the school gates in their 4×4 and park on the zig-zags because Chardonnay can’t walk that far 🙄 If you want to get people like that worried, then plastering a few of these on anything using wifi might do the job

Oh.. I thought you would lead with the fact that WiFi at 2.4Gig is the same frequency as microwave ovens, them being tuned to that as its the frequency needed to excite aka heat water. Yes ovens run at 100 Watts etc But do we see the tinfoil hat wearers go around protesting about microwave ovens and the regular testing of the seals on them or the WiFi AP’s in schools or at homes?

Ah, the reason I didn’t is that industrial ovens actually use lower frequencies, rather closer to mobile phone frequencies, as that is closer to the resonant frequency so more efficient at heating up water molecules. Water molecules get excited by quite a wide range of frequencies.

That and I CBA checking exactly what the relationship is between frequency, power transfer and human health, but it does vary – for example frequencies higher than 10^19 Hz are definitely hazardous 😉

That and I CBA checking exactly what the relationship is between frequency, power transfer and human health, but it does vary – for example frequencies higher than 10^19 Hz are definitely hazardous

From an absorption perspective, penetration of the EM wave into the body (ie, Skin, fat and muscle) lessens at frequencies above ~1GHz. Once you get to about 1.2-1.5GHz the signal does not penetrate much beyond the skin (about 3mm thickness) and anything beyond that falls off rapidly once entering the fat layer. Fat is a very lossy and quite a lot of the power is actually reflected from the skin surface at these frequencies thus not absorbed at all. I have no idea what happens above around 12Ghz as that was the upper frequency of any of the equipment I was involved with.

Anyway, all the base station and handset equipment meets the ICNIRP requirements for RADHAZ (radiation hazard) for both the public and worker exposure levels at the safe working distance. If anyone complains of headaches etc near masts they are suffering purely from a psychological placebo effect (or are just NIMBYs).

Work with GSM a lot of the time, climb radio masts as well. We have NARDA alarms to warn of dangerous RF and even holding it on the face of a mobile sector 30M up it still wont go off! That said the BTS was probably not call handling, just transmitting its BCCH.

there’s very little difference between the dielectric properties of water at ~900MHz (eg mobile frequencies) and 2.4GHz (wifi, domestic microwave ovens)

I think people naturally assume that domestic microwave ovens work at 2.45GHz because it’s most efficient for heating water, when in fact it’s the best Industrial Scientific and Medical (ISM) frequency available for even heating of a wide variety of meal-shaped loads