Wave Height

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Ravenvalor

Senior Member
Hello,

Would someone please explain electromagnetic wave height (or depth)? I am trying to have a grasp of this topic in order to coherently argue the safety of bluetooth technology. I believe bluetooth technology uses around the 2.45Ghz frequency range which has a wavelength of around 12cm. Does the wave height depend upon the amount of energy in the wave?

Thanks,
 

winnie

Senior Member
Location
Springfield, MA, USA
Occupation
Electric motor research
Wave height doesn't really enter into electromagnetic waves. It matters for mechanical things like ocean waves.

I think you might be looking for 'wave length', which is the distance between corresponding portions of a repeating wave. Back to the ocean wave: wave height would be the height from peak to trough, wave length would be the distance between peaks (or troughs). For em waves the corresponding values would be amplitude (related to electrical or magnetic field strength) and length (related to frequency).

The is a relationship between wavelength and photon energy for em waves; higher frequency means shorter wavelength and higher energy per photon. Once energy is high enough, then a single photon can cause chemical ionization. This is the realm of x-ray and gamma ray ionizing radiation.

Microwaves (including bluetooth) are much too low energy to be ionizing radiation. The photon energy is also so low that it is much better to approximate microwave radiation as being continuous for most purposes. But microwave radiation can still do damage.

The classic and known issue is thermal heating. Enough microwave radiation can damage tissue by heating it up.

Currently there is significant debate about the risk of non-thermal injury caused by microwave radiation. I think that there is lots we don't know on this topic. We can set a bound on the risk, because we are exposed to lots of microwave radiation and people haven't suddenly started dropping dead rapidly, but it is plausible to me that there are subtle risks.

A couple of years back there was a preliminary report from the National Toxicology Program study of cell phone radiation. (See https://ntp.niehs.nih.gov/results/areas/cellphones/index.html for a general link, not the prelim report). As I recall they saw some very interesting results, including statistically significant increase in certain heart lesions, but also an increase in over-all life span, when exposed to rather high levels of cell phone type radiation. The levels were high but not 'thermal', and they saw differences in health effects with different types of modulation.

The last result is quite telling to me: my guess is that the radiation itself is not causing the injury directly, but is somehow being 'demodulated' and triggering the body to do things that can cause injury.

Bluetooth: much lower power levels than cell phones, in the same general frequency range, using different modulation. I think you could honestly say that the risk is very very low, but can't honestly say the risk is zero.

-Jon
 

Ravenvalor

Senior Member
So amplitude is the correct way to phrase wave height which is determined by electrical or magnetic field strength?

QUOTE" The is a relationship between wavelength and photon energy for em waves; higher frequency means shorter wavelength and higher energy per photon. QUOTE"

So in the above example higher frequency means higher energy per photon. Does this carry over to higher amplitude?

Thanks for the help....
 

hbiss

EC, Westchester, New York NEC: 2014
Location
Hawthorne, New York NEC: 2014
Occupation
EC
Hello,

I am trying to have a grasp of this topic in order to coherently argue the safety of bluetooth technology. I believe bluetooth technology uses around the 2.45Ghz frequency range which has a wavelength of around 12cm. Does the wave height depend upon the amount of energy in the wave?


It's the same as our volts/current/watts relationship because it's the same thing. I have no idea where you are going with wave height which is the amplitude or voltage. You need to be talking about power.

The higher the voltage fed to a transmitting antenna, the more current that will flow and the more wattage emitted. So it entirely dependent upon the design of the transmitter and antenna as to how much power or wattage will be emitted. As was stated, blue-tooth is very low power and limited range.

As for cell phones themselves, my concern is not with cell towers but the constant close exposure to the phones which equates to many times the exposure you would receive living next to a cell site. But people refuse to understand that.

That said, my wife knows a doctor who had a tumor removed from behind his ear. He swears it's because he was using a blue-tooth earpiece for many years. So there's anecdotal evidence against blue-tooth when used in close proximity to the body.

I hope the people you are talking to aren't the anti-smart meter tin hat crowd.

-Hal
 

winnie

Senior Member
Location
Springfield, MA, USA
Occupation
Electric motor research
QUOTE" The is a relationship between wavelength and photon energy for em waves; higher frequency means shorter wavelength and higher energy per photon. QUOTE"

So in the above example higher frequency means higher energy per photon. Does this carry over to higher amplitude?

No. Higher amplitude carries over to more photons.

The energy per photon is set by the frequency. The discovery of this was one of the keys to the founding of 'quantum mechanics'. There is something called the photoelectric effect. Light hitting metals causing electrons to be emitted from the surface. Experimentally it was found that low frequency light, no matter how intense, did not cause electrons to be emitted, but high frequency light of very low intensity would cause electrons to be emitted. A few high frequency photons alter matter in ways entirely different than lots of low frequency photons with the same total energy.

Very low power levels of x-rays and gamma rays can cause a huge amount of damage, because a single x-ray photon has very high energy and can break important chemical bonds without significant tissue heating. An X ray dose that delivers the same total energy as simply being alive for 5 seconds is enough to kill half the population.

Very high amplitude (or very high power) microwaves will heat you up. High enough power will kill you by cooking you. But so will exposure to hot water. High power microwaves will not break chemical bonds until you reach the point of thermally heating up the tissue to the point where bonds break.

-Jon
 

Ravenvalor

Senior Member
It's the same as our volts/current/watts relationship because it's the same thing. I have no idea where you are going with wave height which is the amplitude or voltage. You need to be talking about power.

The higher the voltage fed to a transmitting antenna, the more current that will flow and the more wattage emitted. So it entirely dependent upon the design of the transmitter and antenna as to how much power or wattage will be emitted. As was stated, blue-tooth is very low power and limited range.

As for cell phones themselves, my concern is not with cell towers but the constant close exposure to the phones which equates to many times the exposure you would receive living next to a cell site. But people refuse to understand that.

That said, my wife knows a doctor who had a tumor removed from behind his ear. He swears it's because he was using a blue-tooth earpiece for many years. So there's anecdotal evidence against blue-tooth when used in close proximity to the body.

I hope the people you are talking to aren't the anti-smart meter tin hat crowd.

-Hal

I think what has got me not buying the bluetooth scare is because I am hung up on the thought that since the frequency is so high the depth in which the signal can penetrate is miniscule. My own experience with high frequency is my home made tesla coil which operates in the Mhz range and therefore the arc created does not even begin to penetrate the skin.

Thanks for all of the great input....
 

hbiss

EC, Westchester, New York NEC: 2014
Location
Hawthorne, New York NEC: 2014
Occupation
EC
I've never heard of the blue-tooth scare. That story I told above actually surprised me when I heard it. I can't believe that people would be concerned about blue-tooth when cell phones are so much more powerful. If you were to be cautious that's where I would start but condemning cell phones is blasphemy.

All it takes is a few stories on the internet to make an ignorant public believe anything. :dunce:

-Hal
 

winnie

Senior Member
Location
Springfield, MA, USA
Occupation
Electric motor research

The linked article that started that thread started with a picture that roughly approximates the damage caused by _ionizing_ radiation on cells. Microwave radiation is _not_ ionizing radiation, that's the whole point about frequency relation to photon energy. Any alarmism based on that misunderstanding is the worst sort of BS.

Current research suggests that there is some risk from microwave radiation, but the data is not clear, and the mechanism is not understood.

My personal hunch (not supported by actual research, just my guessing based on general science knowledge) is that living systems can sometimes unintentionally detect/demodulate microwave signals, and respond to this sensory input. This response could then lead to damage (or benefit). As I stated above, the preliminary data from the Nat. Tox. Prog. study of cell phone RF exposure showed different response to different modulation schemes, and showed an _increase_ in lifetime even though it also showed heart lesions.

-Jon
 

__dan

Senior Member
I have not looked recently or tried to study it. I believe one of the hazards claimed was from high power microwave weather radar, which is kind of a ubiquitous implementation, everyone and everything gets exposed. I would have to look at it again, bleaching of corals may have been mentioned.

Not sure but I may recall the OP in that thread is one of a original independent thinkers, the rare kind.

The best that can be said is that all of the new tech is beta tested on the entire population and because of that improvements are rapid. If we still had 5 watt cell phones with an antenna taped to everyone's ear, there would be some measurable bad side effects,

In biological processes there is a lot going on all the time in chemical process that depend on subtle changes in state and energy level. The chemical transition can be very low power, maybe needing a catalyst. Now the ambient has changed, but the changes has not been put through the evolutionary wringer that would have happened if this was the ambient for the last 1/2m years.

We are still just beginning to look at where all the effects may happen and what they may be. I will add my own anecdote. My yard is a haven for bugs birds wildlife. They live and eat in the yard, it's all grown in and established. I have really noticed the (apparent) insect die off and a lot less birds. Noticed it in my yard but have no clue why.

https://arstechnica.com/science/201...icrowaves-to-learn-how-grapes-create-plasmas/
 
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