How do I detect and measure RF/EM radiation?

[Steve K]

.... 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.

[Paladin]

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

[Paladin]

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!?

[PhotonWrangler]

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.

[BriteIdea]

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