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Mast with this message

Posted: Tue Jan 12, 2016 9:39 pm
by Dan
Anyone know anything about this ? Iv set up on a few masts before but never seen anything like this before. Did some googling but can't really find anything concrete about health issues being near it for a short period.
Image

Re: Mast with this message

Posted: Tue Jan 12, 2016 10:38 pm
by Gum
In a nut shell, don't hang about... ;)

https://www.gov.uk/government/uploads/s ... _35_RF.pdf

Re: Mast with this message

Posted: Tue Jan 12, 2016 10:55 pm
by sinus trouble
Hello Dan! :)
Its most likely just a 'Health and safety' requirement to display warnings like that?
There is many conspiracy theories floating around about mobile phones killing our brains lol
On one hand? the theories are backed up? afterall concentrated RF is used in some cancer treatments to kill bad tissue!
But on the other hand? mobile phones do not produce nearly enough power to cause damage (allegedly)
I should imagine short term exposure wont do any harm? but be aware some antenna can cause serious RF burns if you get too close! lol

Re: Mast with this message

Posted: Tue Jan 12, 2016 11:03 pm
by Dan
I'll literally be at the top for 5 mins max, this mast seems to never get serviced and that's the main reason I was going to use it. Just abit worried seeing this as in the top left it says "non ionising radiation". Did a Google search but I still don't understand lol.

Re: Mast with this message

Posted: Tue Jan 12, 2016 11:25 pm
by Gum
Ionizing radiation Image gives you cancer and radiation sickness.

Non-ionizing radiation Image doesn't....... probably! :)

Like I said, just don't hang about. The dose you receive is the product of how powerful the radiation is and how long you are exposed to it for. Closer you are to an antenna, the more powerful the radiation so limit your exposure accordingly.

Re: Mast with this message

Posted: Tue Jan 12, 2016 11:28 pm
by shuffy
That sign looks old, and if it's Cellnet who put that sign up, then it is old. We haven't had Cellnet since the early 2000's. I'd suggest it's probably high power gear on the mast they're referring to and as Sinus says some (possibly obsolete) regulation that was driving the need to put up the sign. If memory serves, Cellnet were still exclusively using the 900 MHz band for their base stations at that time.

These days of course, you've got 3G/HSPA services on 2.1 GHz and some 4G services (but not O2) use 2.6GHz both of which are closer (but probably not close enough) to the resonant frequency of water molecules :O but as far as I know, and assuming that mast now belongs to O2, the highest frequency they use for cellular phones is 2.1 GHz.

I wouldn't spend too much time up there in any case.

Slightly off topic but I've never understood these "site masts safely" campaigns which say don't plonk a mast on a school, for example. A mobile phone against your head produces way higher field strength in your soft tissue than a base station mast a few tens of yards away, and the weaker the signal received by your phone, the more it will crank up the output power to reach the base station anyway. So, your phone will fry your brain far less if you're closer to the base station. QED.

Re: Mast with this message

Posted: Tue Jan 12, 2016 11:36 pm
by teckniqs
sinus trouble wrote:Hello Dan! :)
Its most likely just a 'Health and safety' requirement to display warnings like that?
There is many conspiracy theories floating around about mobile phones killing our brains lol
On one hand? the theories are backed up? afterall concentrated RF is used in some cancer treatments to kill bad tissue!
But on the other hand? mobile phones do not produce nearly enough power to cause damage (allegedly)
I should imagine short term exposure wont do any harm? but be aware some antenna can cause serious RF burns if you get too close! lol

Yeah but those masts chuck out about 300/400w of GSM frequency and the panels are very directional so when you're on the mast you're (as far as I know) safely unexposed behind them.

....The reason they are so powerful unlike compared to mobiles is because mobile phone receivers are shit and GSM base stations have very good pre-amps which boost the incoming cell-phone signal.

Re: Mast with this message

Posted: Wed Jan 13, 2016 12:10 am
by sinus trouble
Shuffy and tech have made some good points!
the research on this subject is soo vague and inconclusive??? as a hunch? i believe that too much of anything is not good!
Also frequency defo has an effect on my body! i remember once i was working on some audio power amplifiers and was testing them on a frequency generator! suddenly when i went down to around 20hz? i felt a strange feeling of nausea (sick) the speakers were wobbling like crazy but i couldnt hear a thing?? weird mann!!

Re: Mast with this message

Posted: Wed Jan 13, 2016 8:54 am
by thewisepranker
shuffy wrote:These days of course, you've got 3G/HSPA services on 2.1 GHz and some 4G services (but not O2) use 2.6GHz both of which are closer (but probably not close enough) to the resonant frequency of water molecules.
<snip>
QED.
That isn't true. The resonant frequency of water is up in the THz range. It's a common misconception.

Re: Mast with this message

Posted: Wed Jan 13, 2016 9:03 am
by shuffy
I stand corrected - thank you. I still wouldn't spend much time up that mast though.

Re: Mast with this message

Posted: Wed Jan 13, 2016 12:17 pm
by mrillusion
wrap up in tin foil or something lol

Re: Mast with this message

Posted: Wed Jan 13, 2016 2:22 pm
by teckniqs
A tin foil pair of Y-fronts and hat should do the trick.

Re: Mast with this message

Posted: Wed Jan 13, 2016 4:15 pm
by Maximus
All I know is don't stand in front of the panels. If in doubt, build a low sensitivity thingy, like a Geiger counter or dosimeter.
Common sense prevails, plus that picture is years old!


Sent from my iPhone using Tapatalk

Re: Mast with this message

Posted: Wed Jan 13, 2016 4:30 pm
by teckniqs
Yeah it's got a few things growing on it and Cellnet must've changed to o2 about 15 years ago lol.

Re: Mast with this message

Posted: Wed Jan 13, 2016 10:23 pm
by Spokes
I would be very doubtful those panels were even radiating anything anymore! There are a few old derelict masts around you should check you can still get power at the site as some of them are locked off.

Re: Mast with this message

Posted: Thu Jan 14, 2016 5:36 am
by teckniqs
The panels should have been upgraded as the networks get updated.

Re: Mast with this message

Posted: Wed Jan 20, 2016 6:09 pm
by NOYB
It's all about ICNIRP Occupational limit (google it).

Typical base station transmitters are 20-40 watts. But there can be lots of transmitters combined - say upto 8 maximum typically. A dB or 2 feeder loss, then the antenna has about 16-18dB gain. Net effect is that it can combine to +61 dBm (the legal maximum) per carrier - and there might be 8 of them. +61 dBm is a little over 1kW - do you want to hang around for long at 5m away from multiple 1kW RF sources? Probably not.

There is a trend in Europe elsewhere (driven by perception, not science) to make regualations even more restrictive than ICNIRP, so probably a newer sign might have a larger distance to keep clear.

Wisepranker - water molecules have several resonant frequencies, and one of them is around 2.4GHz which is no coincidence the frequency microwave ovens operate at - otherwise they wouldn't heat up your baked beans or whatever!

Re: Mast with this message

Posted: Wed Jan 20, 2016 9:03 pm
by thewisepranker
NOYB wrote: Wisepranker - water molecules have several resonant frequencies, and one of them is around 2.4GHz which is no coincidence the frequency microwave ovens operate at - otherwise they wouldn't heat up your baked beans or whatever!
That is simply not true. Please go and do some reading - you might learn something and it will only take a few minutes.

Re: Mast with this message

Posted: Wed Jan 20, 2016 10:39 pm
by sinus trouble
As we all know, the highest risk of radiation is in front of the microwave parabolics which are more than likely to be facing away from the mast itself!
Magnetrons operate at silly powers (around a kilowatt) and are concentrated into a small cavity which intensifies the energy! not the same thing as a mast!

Re: Mast with this message

Posted: Wed Jan 20, 2016 10:48 pm
by sinus trouble
If you happen to be an engineer maintaining these masts daily? theres a good chance you could be in the firing line lol
The chances of you growing a extra head due to putting up a rig is highly unlikely!!