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Old Mar 12, 2005, 6:29 AM   #11
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let's see... 600kHz is about 500 meters, for which 1/2 wave would be 250 meters or about 800 feet. 1500kHz is 200 meters - 1/2 wave is 100 meters or about 320 feet.
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Old Mar 12, 2005, 7:12 AM   #12
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Alan T wrote:
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As a chemist who spent a lot of his working life trying to cause chemical changes using RF & microwave energy, I agree in principle.

However, you'd have to sit very near the antenna for a long time for it do anything much. All it's going to do is warm you up a bit. There's nothing magic about RF & microwave energy. The energy isn't great enough to break chemical bonds, except by getting you hot enough if you're near enough for long enough. It's NOT like UV radiation, which is able to break chemical bonds, and therefore cause cancer. When you're gently warmed by the sun, it's IR that's doing it. When you're burnt by the sun, it's UV.

Radiofrequency and microwave energy are lower frequency than the visible range - longer wavelength than IR. UV has *higher* energy, *shorter* wavelength, than the visible. The energy per quantum is proportional to the frequency.When you get sunburnt, it's UV that's doing it.

So don't sit for long too near powerful radio transmitters, but don't worry too much about it. Worry about the lethal short wavelength (UV) radiation from the sun. That's why the ozone layer (which shields us) is important!
I never said that the RF will break bonds, I was just informing people of the dangers that can be associated with antenna towers. Everything is dependent on the power and the frequencies. Frequencies in the AM and FM band wont do much other than possibly burn you. Its when you get into the Microwave frequencies 1 GHz and above that you really have to worry. I work with satellite and tropospheric scatter equipment that puts out up to 500W at 7-8GHz and 3000W at 4-5GHz respectively.

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Otherwise might end up getting some permanent health problem, or have kids with three eyes etc.
Depends on the frequencies, most true Microwave transmitters will either make you sterile or unable to have male children. I have been radiated several times at low power levels, feeling sick with a headache and really warm, but no major issues.
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Old Mar 12, 2005, 2:31 PM   #13
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Do you think there would be any ill effects from being 10 feet from a 50kW tower in the AM band?
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Old Mar 12, 2005, 4:05 PM   #14
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Probably not, the frequency is too low. It may give you a headache but there shouldn't be any serious effects.
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Old Mar 12, 2005, 4:50 PM   #15
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Stevekin wrote:
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I am a Microwave Radio technician,
Handy to have one of these as a member.

But looking at Requiem's avatar............................do you think it's too late ?

i do aircraft wxr radar, satcom, HF, and VHF. ok i do commercial aircraft avionics.
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Old Mar 12, 2005, 8:44 PM   #16
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rob_strain wrote:
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Your camera will be fine.

You however may not. I am a Microwave Radio technician, and depending on the power of that antenna, it can be lethal to you.
Off topic here, Rob, but what about cell-phone antennas; they also use microwave radiation, right? We have two of them just about 100 meters or so from our house. I assume that distance is sufficient for the radiation to be dispersed (inverse square and all that), but it's worrisome at times.
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Old Mar 13, 2005, 10:06 AM   #17
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There is probably no danger. I dont know about Japan, but in the US, the frequencies and the power levels used by cell phones are too low to cause any life threatening damage.
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Old Mar 13, 2005, 10:32 AM   #18
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sjms wrote:
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i do aircraft wxr radar, satcom, HF, and VHF. ok i do commercial aircraft avionics.
You remind me that years ago I was walking on the popular beauty spot of Clee Hill in Shropshire, UK. It has a golf ball type of air traffic control radar transmitter on the top. Although I was well outside all the safety fences and a few hundred yards away, my camcorder footage registered a bright flash with with every rotation of the scanner.

So I suspect a digicam would give a very odd result if its exposure concided with one of these flashes.
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Old Mar 13, 2005, 1:46 PM   #19
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The answer to your question is "It depends". On a lot of factors. I am almost certain there will be no permanent damage to your camera, but if the rf energy is high enough, and at the right (wrong, actually) frequency, it can interfere with the recorded image. I have seen posted pictures that were taken near TV and radio transmitters, that did show this. Saw someone try to use a camcorder on Mt. Washington in NH, who got a tape full of the TV station which broadcasts from there, instead of the mountain view. Another gentleman was receiving the audio of the same station trhough his hearing aid.

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Old Mar 13, 2005, 3:10 PM   #20
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yah...true..but they were only affecting the audio right? But if we only take photos, then the picture should be just fine. I guess if you stick the camera very close the a transmitting antenna, then you 'may' get problems with the camera operation, due to the magnetic field linking up with the camera. But we're not going to have the camera that close to the transmitting antenna.
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