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radiotelescope and sterility...
Hi,
We know that during the emission of a radiotelescope (rare, for tests or to send SETI msg, Hi!), the radiation can sterilize people working in the dish. Has someone some idea of the power require to produce such a effect or any generic graph (from IEEE standards ?) showing the risk vs frequency or emitting power ? I have one, http://www.astrosurf.com/lombry/Radi...ower-field.gif but I would like to get a better idea of the power require (in W, Jy, etc). If I had an idea of the require dBi and W , I could compute the EIRP and all concerned values. Thanks in advance Thierry, ON4SKY http://www.astrosurf.com/lombry |
Thierry wrote:
We know... Do we ? ...that during the emission of a radiotelescope (rare, for tests or to send SETI msg, Hi!), the radiation can sterilize people working in the dish. rolls eyes Try tin foil pants to match the tin foil hat. Has someone some idea of the power require to produce such a effect or any generic graph (from IEEE standards ?) showing the risk vs frequency or emitting power ? Health Canada's Safety Code 6. Hint - it's not a dish issue with huge dishes. It might be a feed issue in the worst case. The bigger the dish, the less the issue (the feed being further away). Likely, the 600mW cell phone is worse. And the 5w hand held W/T is even worse than that. If you own a strong magnet and an electric stove, hold the magnet in your hand and turn on one stove top electric burner element to max. Bring the magnet close to the element and feel the very strong vibrations. (Don't burn your hand.) |
Thierry wrote:
We know that during the emission of a radiotelescope (rare, for tests or to send SETI msg, Hi!), the radiation can sterilize people working in the dish. Nonsense - we know nothing of the sort. -- 73 from Ian G3SEK 'In Practice' columnist for RadCom (RSGB) http://www.ifwtech.co.uk/g3sek |
In article , "Thierry" - wrote:
We know that during the emission of a radiotelescope (rare, for tests or to send SETI msg, Hi!), the radiation can sterilize people working in the dish. If "We" know all this, "We" should not be in the dish when these test are being conducted. Duhhhh..... Me |
Thierry wrote: We know that during the emission of a radiotelescope (rare, for tests or to send SETI msg, Hi!), the radiation can sterilize people working in the dish. Nonsense - we know nothing of the sort. -- 73 from Ian G3SEK 'In Practice' columnist for RadCom (RSGB) No-nonsense, it is sense. RF exposure causes temporary sterility, kinda birth control. Too much RF can cook us. Yuri, K3BU.us |
A radio telescope is a receive-only device. It is incapable of rendering
anything sterile. A radar telescope--using a dish--can be dangerous and the EIRP can be megawatts. In this case, a number of health dangers apply. Fortunately those most likely to be exposed are the best informed, and I am not familiar with a single case of dangerous exposure. SETI has nothing to do with this. 73, Chip N1IR |
"Yuri Blanarovich" wrote in message ... Thierry wrote: We know that during the emission of a radiotelescope (rare, for tests or to send SETI msg, Hi!), the radiation can sterilize people working in the dish. Nonsense - we know nothing of the sort. -- 73 from Ian G3SEK 'In Practice' columnist for RadCom (RSGB) No-nonsense, it is sense. RF exposure causes temporary sterility, kinda birth control. Too much RF can cook us. Yuri, K3BU.us Yuri Depends on the fequency. The fact that you're still here confirms it's not too bad. 73 |
We recommend getting a vasectomy instead of microwaving yourself. Its less
painful, and cleaner. |
Fractenna wrote:
A radio telescope is a receive-only device. It is incapable of rendering anything sterile. A radar telescope--using a dish--can be dangerous and the EIRP can be megawatts. In this case, a number of health dangers apply. Fortunately those most likely to be exposed are the best informed, and I am not familiar with a single case of dangerous exposure. SETI has nothing to do with this. 73, Chip N1IR According to a article I read sometime ago the people that built the BWMEWS system in Greenland used to stand in front of the antenna and warm up. Dave WD9BDZ |
Yuri Blanarovich wrote:
Thierry wrote: We know that during the emission of a radiotelescope (rare, for tests or to send SETI msg, Hi!), the radiation can sterilize people working in the dish. Nonsense - we know nothing of the sort. -- 73 from Ian G3SEK 'In Practice' columnist for RadCom (RSGB) No-nonsense, it is sense. RF exposure causes temporary sterility, kinda birth control. Too much RF can cook us. Yuri, K3BU.us I wouldn't depend on it, Yuri. You'd have better luck with the rhythm method. 73, Tom Donaly, KA6RUH |
"Yuri Blanarovich" wrote in message ... Thierry wrote: We know that during the emission of a radiotelescope (rare, for tests or to send SETI msg, Hi!), the radiation can sterilize people working in the dish. Nonsense - we know nothing of the sort. -- 73 from Ian G3SEK 'In Practice' columnist for RadCom (RSGB) No-nonsense, it is sense. RF exposure causes temporary sterility, kinda birth control. Too much RF can cook us. Yuri, K3BU.us First, let's agree on nomenclature; a radio telescope is a receiving device only, it is not an emitter. Feel free to coin a new term for a highly directional, high power emitter used for astronomical research. RF exposure can cause many things, from nothing sensible to boiling to carbonization to vaporization. It all depends on the RF power, the absorption and the time of exposure. Absorption is dependent on frequency and conductivity of the sample. Heating is dependent on the power, the absorption and the ability to transfer heat from the sample. For instance, 14 GHz exposure will result in most radiation reflecting off a human body; move the exposure to 2.4 GHz, and the effective depth of heating will be several inches into the tissues. Move down to 960 MHz, and you will get even deeper heating. (Consider why industrial microwave ovens are at 960 MHz.) Some body tissues are more exposed to RF, and, having only modest blood circulation, have a poor ability to transfer heat. Assuming you are male, those tissues at risk would include your earlobes, fingertips, nose, corneas, elbows, penis, scrotum, testicles and toes. Your earlobes, nose, fingers and scrotum have good circulation, so the blood cooling helps to protect them. Your toes are usually electrically close to the ground, and in a region of lower power density. Your penis is also well cooled and poorly exposed, unless RF exposure gives you a woodie. And who cares what happens to your elbows? So that leaves your corneas and testicles as the most vulnerable tissues. Canadian Safety Code 6 is a well-written document that will also teach you a lot about RF emissions, RF measurement and biological effects. It's limits are based on old ANSI C95.3-1991 work, which has been codified as IEEE STD C95.1-1999. The USA FCC also uses the IEEE standard. Both the IEEE and ANSI want to charge you for access, but Industry Canada courteously provides a free download at: http://www.hc-sc.gc.ca/hecs-sesc/ccrpb/pdf/99ehd237.pdf Thanks, Canada! So we see that RF can do essentially nothing, it can sterilize, it can cook, it can kill, and it can destroy. It's all a matter of power, frequency, target and time. Ed wb6wsn |
Yuri Blanarovich wrote:
Thierry wrote: We know that during the emission of a radiotelescope (rare, for tests or to send SETI msg, Hi!), the radiation can sterilize people working in the dish. Nonsense - we know nothing of the sort. -- 73 from Ian G3SEK 'In Practice' columnist for RadCom (RSGB) No-nonsense, it is sense. RF exposure causes temporary sterility, kinda birth control. Too much RF can cook us. TOO MUCH certainly can, and of course there are many documented cases. It's Thierry's use of "we know" that bugs me. Does anyone actually *know* of any case whe People have been working in (inside) a radiotelescope dish AND The transmitter has been on (most radiotelescopes don't even have one) AND They have become sterile? No, I thought not. That's because it's pure techno-folklore. -- 73 from Ian G3SEK 'In Practice' columnist for RadCom (RSGB) http://www.ifwtech.co.uk/g3sek |
Fractenna wrote:
A radar telescope--using a dish--can be dangerous and the EIRP can be megawatts. More techno-folklore. The only heating power available is the power supplied up the feedline. "Magnification" by the antenna is irrelevant, and EIRP figures only serve to scare people. Actually, the exact opposite is true. RF hazards are a function of power density (mW/cm^2 or W/m^2). The higher the antenna gain is, and the higher the far-field EIRP, the larger the aperture area must be and therefore the lower the power density becomes. The most dangerous antenna is the smallest, for example, an open-ended waveguide or a small horn. That is because all the available power is concentrated into such a small area. Looking into an open waveguide is like looking into the barrel of a gun - you don't do it until you've made darn sure about the other end! But if you take that horn outside and mount it on a big dish where it's hard to come anywhere near, it is immediately much safer. And the larger the dish is, the smaller the RF hazard becomes. Bottom line: "EIRP" and "RF hazard" don't belong in the same sentence - except this one. -- 73 from Ian G3SEK 'In Practice' columnist for RadCom (RSGB) http://www.ifwtech.co.uk/g3sek |
A radar telescope--using a dish--can be dangerous and the EIRP can be
megawatts. More techno-folklore. The only heating power available is the power supplied up the feedline. Well, why don't you go on the catwalk at Arecibo and see if they'll let you try a little experiment while the radar is on. I am speaking from knowledge, my friend. 73, Chip N1IR |
On Mon, 10 Jan 2005 09:09:35 +0000, "Ian White, G3SEK"
wrote: Bottom line: "EIRP" and "RF hazard" don't belong in the same sentence - except this one. Hi Ian, Even more remote is EIRP and nearness (EIRP demands the source appear to be a point so that all phases from the reflector add to produce the EIRP). Another boner is that "a radio telescope is a receive-only device." This bald statement would consign Arecibo to the ash heap of radio telescopes because it has a 430 MHz radar system built into it. I suppose by the same logic, a radar is a receive-only device between pulses. 73's Richard Clark, KB7QHC |
Fractenna wrote:
A radar telescope--using a dish--can be dangerous and the EIRP can be megawatts. More techno-folklore. The only heating power available is the power supplied up the feedline. Well, why don't you go on the catwalk at Arecibo and see if they'll let you try a little experiment while the radar is on. It doesn't matter whether it's Arecibo or just an open waveguide, you cannot ever be heated by more energy than is being supplied by the transmitter. The transmitter supplies all the available energy - there is no other energy source involved - and it all comes out of the feedhorn. If you're on the catwalk close to the feedhorn, and if there is enough energy, then of course you'll feel it. But that interaction involves only the transmitter, the feedhorn and you. The dish and its gain have absolutely nothing to do with it. If the dish were completely removed, you would still experience exactly the same. I am speaking from knowledge, my friend. I know that you possess the knowledge; but that's not where you're speaking from. -- 73 from Ian G3SEK 'In Practice' columnist for RadCom (RSGB) http://www.ifwtech.co.uk/g3sek |
"Fractenna" wrote in message ... A radio telescope is a receive-only device. It is incapable of rendering anything sterile. A radar telescope--using a dish--can be dangerous and the EIRP can be megawatts. In this case, a number of health dangers apply. Fortunately those most likely to be exposed are the best informed, and I am not familiar with a single case of dangerous exposure. SETI has nothing to do with this. Yes it does. My post states in the case of the RT is used (was sued) to send SETI msg, like to Arecibo and others. Please believe, I know what I say. http://www.astrosurf.com/lombry/menu-seti.htm Thierry 73, Chip N1IR |
"Ian White, G3SEK" wrote in message ... Fractenna wrote: A radar telescope--using a dish--can be dangerous and the EIRP can be megawatts. More techno-folklore. The only heating power available is the power supplied up the feedline. "Magnification" by the antenna is irrelevant, and EIRP figures only serve to scare people. Actually, the exact opposite is true. RF hazards are a function of power density (mW/cm^2 or W/m^2). The higher the antenna gain is, and the higher the far-field EIRP, the larger the aperture area must be and therefore the lower the power density becomes. Ok Ian I think that I can compute it now. I know the gain and MW sent by some RT, the RF limits for the health, etc. Thanks. Thierry, ON4SKY The most dangerous antenna is the smallest, for example, an open-ended waveguide or a small horn. That is because all the available power is concentrated into such a small area. Looking into an open waveguide is like looking into the barrel of a gun - you don't do it until you've made darn sure about the other end! But if you take that horn outside and mount it on a big dish where it's hard to come anywhere near, it is immediately much safer. And the larger the dish is, the smaller the RF hazard becomes. Bottom line: "EIRP" and "RF hazard" don't belong in the same sentence - except this one. -- 73 from Ian G3SEK 'In Practice' columnist for RadCom (RSGB) http://www.ifwtech.co.uk/g3sek |
"Me" wrote in message ... In article , "Thierry" - wrote: We know that during the emission of a radiotelescope (rare, for tests or to send SETI msg, Hi!), the radiation can sterilize people working in the dish. If "We" know all this, "We" should not be in the dish when these test are being conducted. Duhhhh..... remark very useful to answer the question Me |
"Ian White, G3SEK" wrote in message ... Yuri Blanarovich wrote: ... It's Thierry's use of "we know" that bugs me. Does anyone actually *know* of any case whe People have been working in (inside) a radiotelescope dish AND The transmitter has been on (most radiotelescopes don't even have one) AND They have become sterile? No, I thought not. That's because it's pure techno-folklore. Where is the problem ? Folkore ? Non sense. You never work with maths ?, you know, these kind of relaiton useless... on the air. but without which there hadn't had antennas either. Why are you all so off-subject ? Is this so hard to answer a question. It is more simple maybe to be involved in controversy... pfff -- 73 from Ian G3SEK 'In Practice' columnist for RadCom (RSGB) http://www.ifwtech.co.uk/g3sek |
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