# How do I detect and measure RF/EM radiation?



## LowBat (Dec 6, 2006)

I maybe moving next to a rather large communications tower. I'm wondering what sort of radiation sould I be concerned about and how do I measure it? I'm guessing radio frequency energy and perhaps electro-magnetic radiation are what I need to be looking for. As I know very little about this stuff, I thought I'd see if we had some expects on board who could enlighten me. I'm also guessing a geiger counter isn't the right measuring device for this type of radiation.


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## carbine15 (Dec 6, 2006)

you need a Agilent 8565EC portable, color display millimeter wave spectrum analyzer.


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## London Lad (Dec 6, 2006)

carbine15 said:


> you need a Agilent 8565EC portable, color display millimeter wave spectrum analyzer.



Might be cheaper to move !


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## LowBat (Dec 6, 2006)

carbine15 said:


> you need a Agilent 8565EC portable, color display millimeter wave spectrum analyzer.


That looks expensive and complicated. I'd venture to say the manual would probably resemble a phone book. Anything a little simpler for a novice like myself?


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## Lasernerd (Dec 6, 2006)

AM radio hooked to Spectrum labs software


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## Steve K (Dec 6, 2006)

It depends on what sort of concerns you have. 

If you are worried about violations of FCC regulations, just verify that your radio, TV, cell phone, cordless phone, etc. still work okay. If there's no degradation in their performance, then you are fine. 

If you are worried about health issues, then I'm not sure what to tell you. Are there any standards? I'm betting that there are some standards regarding how much RF a microwave oven can emit, and I think there are some affordable instruments to measure this emission. Other than this, you may be left with more empirical sorts of experiments. For instance, if you can take a hot dog out of the fridge, set it on a plate on the counter, and it cooks just sitting there, then you probably have a problem with microwave emissions.  

Those are all of the low-cost options that I can think of. The proper way to measure RF levels is indeed to use a spectrum analyzer, and that's not cheap. There are places that rent this sort of equipment, if you are interested. And then there's the question of what level of RF is acceptable. I know the specs for the industry that I work in, but I'm sure that the requirements for (intentional) broadcasting is different.

good luck,
Steve K


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## Outrider (Dec 6, 2006)

Hi Lobat Go to www.trifield.com and check out the "trifield meter". At $ 145.00 these work very well and have been around for years. Not a Lab Standard but will do what you want quite well.


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## carbine15 (Dec 6, 2006)

i read of some studies that showed a correlation between increased beta radiation and healthier offspring, longer lives and fewer diseases. If there's no annoying buzzing sound you should be fine. That buzzing sound is your brain frying, plus it's really annoying.


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## LowBat (Dec 6, 2006)

I just want to get a general idea of exposure levels. It sounds like that trifield meter is about what I'm looking for.

Thanks everyone!


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## geepondy (Dec 6, 2006)

We have to do EMI testing in our products. The product is fired up and a directional antenna is pointed at the object from a set distance. The antenna is attached to a spectrum analyzer where a spectrum sweep is performed. We always pick up a couple of local strong radio stations but they are ruled out because we do an ambient reading first with the unit under test not operating and then subtract the ambient reading when testing with the device on. Let me tell you, it can be a pain in a butt to find and seal the emi leaks in some of the devices.

Not sure of a home EMI cost effective testing solution.


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## Ordin_Aryguy (Dec 8, 2006)

Geepondy,
There's an old saying amongst those of us that have to take prototypes and make them EMC compliant, "Ambients are my friend." More than once I've blazed through a certification test because of the ambients "hiding" a few problem frequencies.

LowBat,
For the most part RF energy decays as a square root of the distance that you are away from the transmitter (this holds mostly true for unidirectional xmtrs, I believe.) Meaning, if you're 10ft away from the transmitter, then move to 20ft away (a doubling of the distance) the power falls off by the inverse of the square root of the distance you moved away, or 1/sqrt(10). You can see that it doesn't take too long to get really small numbers.
You're subjected to MUCH greater levels of RF by putting a cell phone right next to your brain!


Ordin


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## hopkins (Nov 15, 2007)

A simple way to detect RF is with an AM radio. Walk around your home with
a portable AM radio, turned up loud and hold it near your computer monitor,
television, fluorescent lights, electric bed blankets, microwave ovens,
cell phone LCD displays, digital wrist watch, Regulated LED headlamps,
digital camera, etc.

Some devices emit RF when turned OFF but plugged in an AC outlet.

-notice non-regulated LED lights do not emit RF.


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## TedTheLed (Nov 17, 2007)

well for what's it's worth I know when the Navy is on high alert because they increase the radar power which causes tiny interference dots on my DTV screen.. they are tiny little dots, about the size of a period. "." and are distributed in a 'dancing' grid pattern across the screen.. it's ominous when they appear, sometimes at night, you wonder what they're searching for out there..


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## James S (Nov 18, 2007)

is it just a cell phone tower? Those things are pretty closely regulated and even with a bazillion people using transmitters a few inches from their brain the studies that might show an effect are still so close to the nose level that there is unlikely to be any real effect there. So your exposure by living near a tower where you're a lot further from the transmitters isn't likely to do anything bad to you at all even over the long term. At least according to any of the current data. 

you will want to read the wikipedia article on the Inverse Square Law and understand that your exposure will be very small.

It's really not worth stressing over. If there were a real effect of living under the thing it would show up quite clearly on the data. Afterall there are a LOT of these things, especially in urban areas where people often live right inside an apartment with the antennas mounted right outside their bedroom windows.


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## TedTheLed (Nov 18, 2007)

the electrical activity of the brain is so tiny that the most sensitive instruments man has made are needed to measure the magnetic fields they produce outside (!) the brain. see the 'squid' device-- http://www.lanl.gov/quarterly/q_spring03/squid_text.shtml

a little research turns up much to indicate that magnetic fields applied to the brain most definitely affect thought, and even the ability to discern truth from falsehood. I can't help thinking that the immense magnetic fields present in everyday life both man made and cosmic have a profound affect on our brains..


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## PhotonWrangler (Nov 18, 2007)

LowBat said:


> I just want to get a general idea of exposure levels. It sounds like that trifield meter is about what I'm looking for.
> 
> Thanks everyone!



I've had a TriField meter for years and I like it. While it's not going to be anywhere nearly as sensitive as the labratory grade instruments, it will tell you if there's an unusually large amount of RFI or EMI in the immediate area.

Having said that, RF energy falls off in intensity with the inverse-square law. In other words, as soon as it leaves the antenna, the field strength goes way, way down.


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## hopkins (Nov 18, 2007)

Hi Tedtheled - There was the scifi novel 'The Terminal Man' about putting
wires into a guys head to control his violent seizures. No inverse square
law reduction for that situation. 
Whats seems to true is that people can think themselves sick as well as
spontaneously cure themselves, ie the placebo effect. 
So lets not worry about low power RF from flashlights.


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## James S (Nov 19, 2007)

TedTheLed said:


> the electrical activity of the brain is so tiny that the most sensitive instruments man has made are needed to measure the magnetic fields they produce outside (!) the brain. see the 'squid' device-- http://www.lanl.gov/quarterly/q_spring03/squid_text.shtml
> 
> a little research turns up much to indicate that magnetic fields applied to the brain most definitely affect thought, and even the ability to discern truth from falsehood. I can't help thinking that the immense magnetic fields present in everyday life both man made and cosmic have a profound affect on our brains..



they measure the miniscule magnetic effects because in order to measure the actual electrical (or chemical) signals they would need to open up your head and stick pins in your brain 

And yet we can put you in a MRI scanner with a magnetic field above 3 teslas (which is HUGE, big enough to pull an iron gas canister across the room and decapitate the tech standing next to the machine, this has happened and is one way that very large magnetic fields are really dangerous!) and you can sit there quite happily and the iron doesn't get pulled out of your blood (the iron as chemically bound in hemoglobin is completely 100% non-magnetic which is why anybody that wants to sell you a magnet to do something to your blood is selling snake oil) and the fields that run your thoughts inside your head remain completely unaffected by that.

Then there is the fact that there is a bit of a difference between magnetic fields and radio frequency fields. These things all interact very weakly or not at all in any level you're likely to experience outside of a laboratory (or some of the folks around here in the basements  ) Remember that the ability of microwaves to heat food was not discovered because of any effect it was having on people, but rather because the people working in operating radar dishes who were otherwise completely unaffected found that chocolate bars in their pockets would melt.

You are not so sensitive to low levels of electromagnetic, radio or magnetic fields. The reason we have government agencies is to find out how much before there is an effect. They do a fairly decent job of protecting us from poisonous levels of all sorts of things. They generally find the lowest level from something for which it has been demonstrated that there is no effect, and then decrease what they consider to be the "safe" exposure level another order of magnitude or more below that just to be sure.

So you're already being exposed to an order of magnitude less RF from those than has ever been measured to have any kind of effect at all.

There was a really wonderful "stunt" pulled in the UK a couple of years ago. There are always people who are worried about the effects of a new tower. After a new tower went up in some town the locals were interviewed about how they think it affected their health. Many people did claim that it had made them dizzy or sick or increased pain or various other vague symptoms. The joke was that they hadn't actually turned it on yet. So indeed, you can think yourself sick, but the tower wont make you sick. Do not let yourself worry about it! Worry and stress are far more destructive to both your physical and emotional health than a little stray RF.


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## TedTheLed (Nov 19, 2007)

James, sure we notice when the RMI machine sucks up gas cannisters, or would notice if it pulled the iron out of our veins while lying there, but what about subtle, miniscule changes in thought itself? Nothing blaring and grotesque but just enough to confuse the line between right and wrong, (has been done in the lab) just enough to get you to think drinking that infamous glass of 'koolaid' would be just the thing to do right now..
even if the guberment did know about such effects, would you trust THEM to inform you?

and this minimalisation of the rf energy by quoting the square inverse law makes me wonder how come any Beethoven comes out of that little box at all..obviously some of the energy travels great distances to perform the miracle..


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## James S (Nov 19, 2007)

TedTheLed said:


> James, sure we notice when the RMI machine sucks up gas cannisters, or would notice if it pulled the iron out of our veins while lying there, but what about subtle, miniscule changes in thought itself? Nothing blaring and grotesque but just enough to confuse the line between right and wrong, (has been done in the lab) just enough to get you to think drinking that infamous glass of 'koolaid' would be just the thing to do right now..
> even if the guberment did know about such effects, would you trust THEM to inform you?
> 
> and this minimalisation of the rf energy by quoting the square inverse law makes me wonder how come any Beethoven comes out of that little box at all..obviously some of the energy travels great distances to perform the miracle..



 Beethoven comes out of the box because of the wonderfulness of the amplifier circuit which uses the miracle of the transistor or vacuum tube. Those are necessary to take the microvolts that the RF in the air are able to induce in the antenna and turn them into a voltage level which the rest of the system can work with  You need the box because you have no tools built into your body to receive or listen to that kind of energy.

Just because we are able to build a machine that can detect a thing it does not therefore follow that the levels we are able to detect cause an effect on our bodies. The dose makes the poison. There was a measurable amount of arsenic and cyanide in whatever you drank with your dinner, there is a measurable amount of botulinum toxin in the honey you put on your toast yesterday and there is a measurable amount of gamma radiation flowing through your body right now. But none of it begins to reach a level when it will have an effect on you. Pump the levels of any poison or toxin high enough and it becomes toxic and poisonous but it does not necessarily follow that therefore any detectable level of those things is bad for you.

There is actually some good data now that shows that very long term high level exposure to cell phone radiation might cause the level of harm to rise above the noise level. Greater than 10 years of headset use daily. But its still hard to see. Science isn't bad at finding these things. They can measure very very small effects given a large enough sample and yet these kinds of exposures still do not rise above the noise far enough that they are certain there is anything there at all. But, instead of trying to cover it up and join a vast governmental conspiracy instead they publish their data in the open and continue to gather more data to try to answer the question once and for all.

I know the government and many folks at various universities have experimented with inducing mental things by injecting rf and mangetic energy directly into the brain. There was that guy at some university that can induce both the sensation of intense religious epiphany and feeling that "this means something!" even when it doesn't. But that doesn't mean that those signals can be broadcast from a cell phone tower. It requires more resolution to your head than that, you have to wear a helmet covered in electromagnet coils 

I dont know about you, but most RF energy passes right through me without any effect at all. My brain relies on both chemical and ionic/electrical methods of sending pulses around that are not so easily disrupted.

Nope, I'm not buying that it does anything to you until somebody shows that it does. Someday the government might pull out it's less-lethal crowd control fear generator gun based on some RF technology, but thinking that they can do anything to you through a cellphone tower is more suited to a novel... perhaps I'll write a novel about it


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## TedTheLed (Nov 19, 2007)

James, I didn't mean just cell phone towers, but, what IF cell phone towers made SOME people a little more nervous, a little more suspicious, angry, 
paranoid, or depressed? Again I'm not talking tumors and death here, but subtle personality changes.. How would we possibly notice or discover this without a thorough campaign of questioning and examination of the people and the lives they live around the towers?
The only government I've heard of that actually asks it's subjects how they are feeling is the Tibetan, and they just want to know if you're happy.

There IS an experiment that has been done, with the subjects wearing helmet devices that generate very mild magnetic waves, that DID change their perception of truth and falsehoods. The waves affected what was called the "repudiation effect" of the brain, that is they eliminated it, so what a subject would normally say is false, they say is true under the waves affect -- I'll try to find it. Just saw it yesterday on TV..


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## PhotonWrangler (Nov 19, 2007)

I know a guy who claims that he gets disoriented by strong magnetic fields.

This was somewhat "confirmed" when a co-worker who knew about his claim brought a large, powerful magnet within an inch of the back of the guy's head without his knowledge. He immediately became disoriended without knowing why.

You decide... :thinking:


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## scott.cr (Nov 20, 2007)

I work for a company that manufactures high-power RF amplifiers. RF exposure is not a concern here, but RF burns are.

Medical MRIs use very high-intensity RF fields to induce proton spin. They do not consider this to be a hazard because it is non-ionizing ("radioactive") radiation.

However, that does not mean *I* trust "them" hahaha. While online Christmas shopping yesterday, I came across the Ramsey Tri-Field Meter kit. It's the lowest-cost tri-field meter I've seen @ $65.


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## James S (Nov 20, 2007)

And if you do pick up the meter and find their output to be out of spec from what is allowed, you can call in the authorities and get them slapped with some not-insignificant penalties. So check up on them if you're interested, but dont be worried just because some RF is passing through you!


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## hopkins (Nov 22, 2007)

Hi Lowbat
Recently noticed that when our neighbor turned on their laundry room fluorescent light AM radio reception was scrambled by loud 60hz buzzing.
I went over with a new ballast, explained to her the problem and got a free
drink after the repair. 

Einstein said:
*You see, wire telegraph is a kind of a very, very long cat. You pull his tail in New York and his head is meowing in Los Angeles. Do you understand this? And radio operates exactly the same way: you send signals here, they receive them there. The only difference is that there is no cat*


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## BigusLightus (Nov 25, 2007)

LowBat,

The simple answer is to check the web and find the local Ham Radio Club. There will be some serious radio geeks there with serious equipment. They will be able to help you out and they will probably find it to be an exciting challenge.

James
KF4WXH


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## LowBat (Nov 26, 2007)

Wow, I'm surprised this thread is still going. I no longer have a need for a detector as the place I was thinking of moving to (lots of antennas and electrical equipment) didn't happen. I do thank you all for your input.


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## jrmcferren (Nov 26, 2007)

BigusLightus said:


> LowBat,
> 
> The simple answer is to check the web and find the local Ham Radio Club. There will be some serious radio geeks there with serious equipment. They will be able to help you out and they will probably find it to be an exciting challenge.
> 
> ...




Yes, what you are looking for is a field strength meter. Do not use an AM transistor radio for this purpose as it will be prone to front-end overload. Find out what is on this tower we may be able to help with that info.


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## Joe_Beam (Jun 3, 2011)

While keeping the "inverse square law" in mind, there are antenna directional characteristics to consider. Most high power transmitters feed directional antennas. In these cases there may be less radio frequency emissions close to the bottom of the tower than there are when you move a slight distance away, at that point the inverse square law comes into effect. The frequency of the emissions determine the distance from the tower that you start to receive full power with respect to the type of antenna. If you are close to a tower, you can get the radiation info from the engineering department of the antenna owner. All commercial antennas are registered with the FCC and they also have this info.

PS: I know that the plural term for antenna is antennae (I'm just trying to keep it simple)


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## Steve K (Jun 3, 2011)

hopkins said:


> Einstein said:
> *You see, wire telegraph is a kind of a very, very long cat. You pull his tail in New York and his head is meowing in Los Angeles. Do you understand this? And radio operates exactly the same way: you send signals here, they receive them there. The only difference is that there is no cat*


 
I forgot about that quote.. I may have to name my next cat "Ether". 
(my current cat is named after Tesla)

Steve K.


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## Steve K (Jun 3, 2011)

TedTheLed said:


> .... I can't help thinking that the immense magnetic fields present in everyday life both man made and cosmic have a profound affect on our brains..


 
but what if it was the magnetic fields that made you think that???

Generally speaking, I'm not aware of experiencing large magnetic fields in my daily life. The earth's magnetic field is probably the largest field I encounter on a regular basis. The next might be the little earbuds for my mp3 player/radio. I've had an MRI done on my brain too. I'm unaware of any mental/emotional/orientation effect of any of these. 

As part of my job, I've spent a while working with rare earth magnets (500 gauss), use a gauss meter to measure fields, have built a helmholtz coil to generate modest uniform magnetic fields (50 gauss), and even made magnetic field measurements at a scrap iron handing plant (and measured the field at one of those giant electromagnets that they use to pick up the scrap iron!). I haven't noticed any effect as a result of being in proximity to magnets or magnetic fields.

I think there are risks to working around large electromagnetic fields. I've heard of stories of folks working with microwave communications amplifiers that put out enough power to make a bird go *pop* when it flew in front of the feedhorn antenna. The stories also say that if there was a RF leak in the room with the amplifier, they would feel sick. Obviously, these fields are hugely larger than anything most folks are exposed to. I don't know that I've ever heard any explanation of what the mechanism of the cause of such RF illness might be, and I've only heard this from a friend who heard it from someone else. 

Since I do work with RF equipment as part of an EMC test lab, I'm careful about avoiding exposure when our amplifiers are running. The routine exposure to electromagnetic fields don't cause me any concern, though... (but I don't use a cell phone either.  )

Steve K.


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## Paladin (Jun 3, 2011)

I used to climb microwave towers. One project in a D.C. suburb met opposition from local residents concerned about the emi. The testing by a third party company found the levels to be minimal.

A far greater hazard is from dropped objects when maintenance is performed. Don't ask me how I know...

Paladin


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## Paladin (Jun 3, 2011)

I used to climb microwave towers. One project in a D.C. suburb met opposition from local residents concerned about the emi. The testing by a third party company found the levels to be minimal.

A far greater hazard is from dropped objects when maintenance is performed. Don't ask me how I know...

Paladin

eta: double post from site issue!?


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## PhotonWrangler (Jun 3, 2011)

Paladin said:


> I used to climb microwave towers. One project in a D.C. suburb met opposition from local residents concerned about the emi. The testing by a third party company found the levels to be minimal.
> Paladin


 
I did an informal test at a microwave transmitter site once. There was a 10' Andrews parabolic with a +9dbm input from the transmitter, running around 13ghz. The primary lobe of the signal was quite tight, however it was still able to drive a radar detector absolutely nuts on the ground, about 75' from the tower. Even so I felt quite safe as this was still a very low level signal at ground level.


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## BriteIdea (Jun 6, 2011)

This is the exact industry that I work in and I detect leaking RF coming from cable plants. Add to that I'm also a ham operator. The amount of RF that I detect is measure in micro-volts. We are also watched by the federal government guide lines and our idnexes are quite low.. Our measurements are in the VHF and UHF zone, while others can be in the 900MHz to GHz zones. 

Please remember that any transmission site is strictly monitored by federal goverment and is why all these sites have to be licenced before they are approved.

The wost that anyone has to be concerned about is the typical cell phone that is commonly "glued" to a users ear. I don't know much about the details of cell phones so can't comment. The diffrence being is that it's the close proximity of cell phones to the human body.

As for any other RF "nearing" the human body you must also be aware of the inverse square law, which states that the RF power diminishes exponatially per distance away from the source.

If, for example you literally lived right under the tower and expose there for a long time, then you should, or could, have concerns. But if that same tower is across the road, that inverse square law takes over and the amount of power is insignificant. 

I'm sure there are others that are better informed on the absolute details but my perspective is based on general theory and documentation.
Maybe it would be best to call your local FCC or Industry Canada Office and get the information straight from the horse's mouth.
Hope that helps


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