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Thread ID: 44253	2004-04-13 08:30:00	How to block radio signals / Monitor radiation reduction	KingWave (5517)	Press F1

Post ID	Timestamp	Content	User
229008	2004-04-13 08:30:00	1) I've got a number of radio/wireless devices in my room: Woosh, mobile, radio, cellphone. I'm thinking that all these radio signals can't be good for me, although I don't think anyone has proved it yet. The booster antenna for woosh sits on the window, so would it be possible to minimise the radio waves coming into the room, by making some type of Farady Cage and covering the whole window frame, but behind the woosh booster antenna, so that can still receive signals and set it down the line to the Woosh modem. 2) My 17" monitor is quite bright, and I have to sit quite close to it, and I'm worried about the radiation emitting from it. Can you buy glare/radiation reduction screens to put over it???	KingWave (5517)
229009	2004-04-13 08:55:00	Line the room with copper or lead, no windows... (Broadcasting Corporation had rooms just like that). Its possible that this radiation is harmful, perhaps the next generation will know more than us by the effects they see in us. However, I would be just as worried by the lower frequency radiation. If your 17" monitor is CRT then the light sourced radiation and the RF radiation you are exposed to is a minute amount compared to the low frequencies of Electro Magnetic Radiation from the monitor (that is almost impossible to block). Same for TV. You can buy glare filters for screens. The faraday cage over the window would need to be constructed in such a way that it did not act as a reflector at the wrong wavelength for Woosh or it would lower the signal by cancellation. It would inhibit the light as well. I use an external cellphone antenna located >10 m away to minimise exposure, plus use LCD monitors. Billy T would have good info on this area, hopefully he will post on the subject.	godfather (25)
229010	2004-04-13 09:08:00	> 1) I've got a number of radio/wireless devices in my > room: Woosh, mobile, radio, cellphone. > > I'm thinking that all these radio signals can't be > good for me, although I don't think anyone has proved > it yet. > > The booster antenna for woosh sits on the window, so > would it be possible to minimise the radio waves > coming into the room, by making some type of Farady > Cage and covering the whole window frame, but behind > the woosh booster antenna, so that can still receive > signals and set it down the line to the Woosh modem. Yes, it is possible to back-screen RF emissions from your Woosh antenna, that is providing it is a boosted up-link not a boosted receive antenna. However, it is probably not worth your while to even try as the emission levels are minimal. What do you mean by mobile, radio, cellphone? The cellphone is easy to deal with so I'll come back to that, but what is the mobile, and what is the radio? Are they both transmitting devices or just receivers?. > 2) My 17" monitor is quite bright, and I have to sit > quite close to it, and I'm worried about the > radiation emitting from it. Can you buy > glare/radiation reduction screens to put over it??? Screen brilliance has virtually nothing to do with screen emissions as it is simply visible light, so if you don't like how bright it is, just turn down the brightness and give your eyes a break. As far as emissions are concerned, all modern monitors conform to the Swedish MPR and American TCO emission standards, which in simple terms means that provided you stay at least 50cm from the screen there are no emissions to speak of. I have never checked a modern screen and found emission levels higher than MPR/TCO. Note I use the word emissions, that is because the term "radiation" is extremely emotive and conveys the spectre of ionising radiation. Ionising radiation comes from radioactive materials, X-rays, cosmic radiation from space, radon gas from the earth etc and generally speaking is "not a good thing" however you are exposed to it constantly whether you like it or not by virtue of your existence on this planet. Back to the cellphone, of all your devices, only the cellphone is a potential problem, and that is because the transmission powr levels are capable of heating up your brain after about 5-10 minutes. The further away you are from the nearest cell site the more powerful you phone's output becomes. If you get a chance, watch a guy with a shaven head talking on his phone. If he talks long enough you will see a pink patch appear on his scalp adjacent to the phone. Only works with pakehas though, brown heads don't go pink eh! Digital phones transmissions are more invasive than analogue, and they tend to need stronger signal levels so they can sometimes transmit at higher power levels than the analogue equivalent. I won't have a digital phone until I have to. I am sticking with analogue.:| That'll do for now, but I have given generalised answers only. If you have specific questions post the necessary info about your devices and your specific questions and I'll reply as soon as I can. Beware of mumbo-jumbo! Cheers Billy 8-{)	Billy T (70)
229011	2004-04-13 09:18:00	Here's an old post (pressf1.pcworld.co.nz) that gives some specifics on monitor radiation. You will have to go down to the ninth, tenth and eleventh posts to find it though. Cheers Billy 8-{) P.S. Thanks for the testimonial Godfather I'll reciprocate when I get the opportunity	Billy T (70)
229012	2004-04-13 14:00:00	Hi, thanks Godfather and BillyT for the comments :) > You can buy glare filters for screens . But these don't stop much radiation getting through?? They just stop glare?? Do they not have anything that can block some of the more harmful stuff coming out of the monitor? Where do you buy them from? > The faraday cage over the window would need to be constructed in such a way that it did not act as a reflector at the wrong wavelength for Woosh or it would lower the signal by cancellation . It would inhibit the light as well . I guess thats true . Would the copper wire absorb the radio frequencies or reflect?? How big would the holes in the wire mesh have to be? Can the radio signals still penetrate through outside walls etc (brick/roughcast)? Or walls separating rooms in your house? (wood/plaster) Even if I decided to go ahead and make one, how do I go about doing it? Does the wire have to be grounded? That would mean drilling a hole through the carpet? ;) > I use an external cellphone antenna located > 10 m away to minimise exposure Can you explain that in more detail? > What do you mean by mobile, radio, cellphone? Whoops I repeated myself there . I just have Woosh, a cellphone thats in the room all the time, and occasionally I use the radio on my stereo . No WiFi devices just yet . > If you get a chance, watch a guy with a shaven head talking on his phone . If he talks long enough you will see a pink patch appear on his scalp adjacent to the phone . lol, I'll be on the lookout! :p > Back to the cellphone, of all your devices, only the cellphone is a potential problem, and that is because the transmission powr levels are capable of heating up your brain after about 5-10 minutes . The further away you are from the nearest cell site the more powerful you phone's output becomes . Yeah thats possibly my main worry . Not sure if its a good idea to have a cellphone next to your bed while sleeping?? > I won't have a digital phone until I have to . I am sticking with analogue . Yeah my cellphone is digital - Telecom CDMA . Woosh is W-CDMA, also digital . :( > Here's an old post that gives some specifics on monitor radiation . You will have to go down to the ninth, tenth and eleventh posts to find it though . Yes I read through that, very interesting . So the monitors with apeture grill technology stop a fair bit more 'rays' coming through than normal ones?? I guess If I had my way, I'd make a small box thing, with the inside lined with copper mesh, and put that right around the booster antenna, and have only the front of the antenna facing the window . That would conceivably seal off the antenna, but I guess radio waves would come through the window anyway??	KingWave (5517)
229013	2004-04-13 16:17:00	OOOOH Ill have to stop reading these boards, you guys scare me silly. Here I am sitting with my wireless keyboard and mouse, wearing my wireless MP3 player headphones, beside my wireless baby monitor, (so I can hear the phone ring), and sitting much closer to my monitor than 50cms. Too much in one room for one ageing bod would you say? What to do? More importantly though what do you think of this teen craze of sleeping (when they are not texting) with their cell phones on all night on their pillow in case a text comes in? I can see glowing heads all over the country. I think you technowizards need to spread the word in your columns, websites, boards etc or soon we will see a whole generation of teens - mainly girls I think- dead from brain tumours. I know I know, Ive done my best to warn and ban, but whats a mere mother compared to a geek? In praise of whom can I just say as a newbie what a world it would be if it was a PC World;) All these wonderful people giving their time and advice free from the goodness of their hearts to help us lesser mortals ie Newbies and Dummies. What a wonderful world. In my genealogy forums we call them SKS - Some Kind Souls - and thats what you all are. Blowin kisses. I wish I knew how to add emoticons to these sites my Smiley Central cant do it.	leonie (5511)
229014	2004-04-13 22:33:00	> I wish I knew how to add emoticons to these sites my Smiley Central cant do it . Leonie, if you go to the Help page (link top right of this page) it tells you there how to add smilies/emoticons to your posts . Basically all you do is type in the ASCII characters for the emoticon you want, eg for a smile you would type :- ) (without any spaces between the characters) . :-) Click on the Emoticons link above the reply box to see what characters you need to type for each emoticon .	Susan B (19)
229015	2004-04-13 23:03:00	> > You can buy glare filters for screens. > But these don't stop much radiation getting through?? > They just stop glare?? Do they not have anything that > can block some of the more harmful stuff coming out > of the monitor? Where do you buy them from? They are just what they say, glare filters, but those with a flying lead to ground the filter use a form of conductive glass that stops high frequency electric fields from passing through. These fields are not generally associated with health effects, though they have been known to cause facial dermatitis effects in people with sensitive skin. The worst offender though is the static field from the EHT supply as this can charge the screen up to several thousand volts. Dust and other particulate matter drifting around in the air may be positively or negatively charged, and since opposite charges attract and like charges repel, the negative particles will be atracted to your screen (which is why computer monitors get much dirtier than anything else in an office). Positively charges particles will be repelled and will naturally seek out the nearest negatively charged object, which happens to be the user because you are grounded via your chair and floor contact, and also via the home keys (F & J) on your keyboard which are meant to be conductive (provided it is not an el-cheapo model). Most modern screens have an antistatic treatment but cleaning the screen too much can destroy the anti-static properties. An add-on grounded screen effectively blocks the static field. Good static screens cost money though, so beware cheap models without the flying lead. I have also seen models with fake leads that were just plastic! To be effective the flying lead must be grounded to earthed metal, not to keyboard trays or penholders etc which are common choices. The securing nut on a serial or parallel port is usually the only earthed metal available on a modern computer or perhaps the PSU fan grille > > The faraday cage over the window would need to be > constructed in such a way that it did not act as a > reflector at the wrong wavelength for Woosh or it > would lower the signal by cancellation. It would > inhibit the light as well. > I guess thats true. Would the copper wire absorb the > radio frequencies or reflect?? It reflects in most cases, but if well grounded some absorption occurs. > How big would the holes in the wire mesh have to be? For cellphone frequencies, something like flyscreen mesh would be about right. Lower frequencies can be screened with chicken wire! > Can the radio signals still penetrate through outside > walls etc (brick/roughcast)? Or walls separating > rooms in your house? (wood/plaster) They are electromagnetic signals and pass freely through virtually every material other than those that are highly conductive, i.e. metals. > > Even if I decided to go ahead and make one, how do I > go about doing it? Does the wire have to be grounded? > That would mean drilling a hole through the carpet? If it makes you feel more comfortable, by all means make one but the practical effect would be almost impossible to measure as you are permanently surrounded by radio signals at all times and from all sides. If I were to take my communications receiver into your room, with just a short whip antenna I could listen to stations all over the world and pickup many non-voice transmissions as well. To be able to do that means the electromagnetic signals from those stations are already present within your room. In fact, it is highly likely that the signals in your room from your local TV stations are already much higher than your Woosh signals. Scary isn't it? > > I use an external cellphone antenna located > 10 m > away to minimise exposure > Can you explain that in more detail? GF attaches an external antenna to his cellphone to take the radiating signal away from him the user. This is helpful but is only partially effective and the other half of a transmitting antenna is the earthing system which acts as a counterpoise to the radiating antenna. Expressed very simply, for cellphones the counterpoise is your hand holding the phone plus the conductive mass of your head and brain. This also causes "hot ear" syndrome for serial cellphone users, I kid you not! > > What do you mean by mobile, radio, cellphone? > Whoops I repeated myself there. I just have Woosh, a > cellphone thats in the room all the time, and > occasionally I use the radio on my stereo. No WiFi > devices just yet. Your radio is a non-event, enjoy. > > Back to the cellphone, of all your devices, only > the cellphone is a potential problem, and that is > because the transmission powr levels are capable of > heating up your brain after about 5-10 minutes. The > further away you are from the nearest cell site the > more powerful you phone's output becomes. > > Yeah thats possibly my main worry. Not sure if its a > good idea to have a cellphone next to your bed while > sleeping?? Just turn it off, but if you can't do that for some reason, don't worry as it will not transmit very often if it stays in the one place. Cellphones use a non-voice channle to maintain contact with the nearest cellsite so they can transmit withot you even knowing! This is a good reason for not having a digital cellphone too close to your computer and those data bursts can play havoc if the timing is right (wrong!) > I guess If I had my way, I'd make a small box thing, > with the inside lined with copper mesh, and put that > right around the booster antenna, and have only the > front of the antenna facing the window. That would > conceivably seal off the antenna, but I guess radio > waves would come through the window anyway?? Not worth the effort, see my earlier comment re commercial broadcast signals. I wouldn't get paranoid about all this, just limit digital cellphone use (saves megabucks anyway) and get on with life. I earn my living going into electromagnetically hostile environments, I spent years bench-working on radiotelephone transmitting 25 watts into a whip antenna 200mm from my head (ah, ignorance) and I h2vn$t be*n a^^ect%d at all. Cheers Billy 8-{)	Billy T (70)
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