If your serious about getting into this, you should get a licence for the 13.56MHz band.

I dont know the ins and outs for obtaining such a license, but I would start with the HAM sites.

Or better yet, FCC's website.

 

47 CFR is the Telecommunications Act. It is commonly called the FCC Rules and Regulations.

You can see the breakdown of the CFR ... with links ... at http://www.fcctests.com/47CFR.asp

You were on your merry way to do whatever you thought would work ... and someone even pointed to a document where someone was obviously unfamiliar with 47 CFR, and disregarded the frequency band assignments, I figured you were going to follow suit.

Bill gave you one frequency you can use.

 

Thanks. I visited the website but here's the issue. I don't know what my experiment falls under. I mean, the document is hard to read and it doesn't say anywhere (that I know of yet) these are open public frequencies and these are not. They just tell you the frequencies assigned to different countries and all. I sent them an email and hopefully they'll be able to clear it up.

P.S. Does anyone know anything about the 135 - 137.8 KHz band? According to the internetz its also open for anyone to use, can anybody confirm this please?

 

Since you're not actually broadcasting on the frequency and explicitly trying to avoid RF radiation I don't believe these particular rules apply to you (unless you just fail at it and radiate significantly anyway).
The ones you'd be worried about are the radiated emissions rules, which simply give you maximum limits for radiation at different frequencies.

http://www.ce-mag.com/99ARG/Gubish31.html

If you have harmonics (which you will with a square wave) you will enter much higher frequencies accidentally.

I could be wrong, I'm not that familiar with the regulations.

 

135 kHz is in the marine band and the fcc granted limited amateur radio (ham) use with an effective EIRP of 1 or 2 watts ... as it is currently proposed. I didn't see anything authorizing it, although the ECC (European) has already proposed the same thing.

If you use transmit than 100 mW power, you fall under the FCC's rules and regulations.

To reduce your electromagnetic emissions, build a screen room.

 

Or whatever the Canadian equivalent is. It is worth researching though, I doubt you want to find out the hard way.

 

Ah, okay. I see. I just wanted to know what the public open frequencies were so that just in case I DO radiate I would be safe and all despite my experiment is supposed to use mainly magnetic fields and very very little RF radiation. I will be tweaking here and there so I just wanted to be safe in case it did radiate RF.

According to your link Ghar,

Subpart C: Intentional Radiators (15.201–5.255)
FCC approval is not required for home-built devices, but such devices must not cause interference.

Frequency (MHz)​

Field strength (µV/m)​

Measurement Distance (m)​

0.009-0.490​

2400/F (kHz)​

300​

0.490-1.705​

2400/F (kHz)​

30​

1.705-30​

30​

30​

30-88​

100*​

3​

88-216​

150*​

3​

216-960​

200*​

3​

Above 960​

500​

3​

How do you measure the field strength? Is it just my peak voltage from the generator divided by the distance at where I take the measurement at?



Also, how do you know how much power you are radiating? I mean, is it just my current output multiplied by my peak voltage output in the signal generator?

 

http://www.fcc.gov/oet/faqs/elbfaqs.html

This says any non-govenment frequency is open for experimental use .... assuming you have a license to operate whatever. Your license will specify the frequency, emission, etc, for your experimental station.

It also makes great assumptions on your equipment.

As far as electromagnetic fields radiating ... consider the power lines and the studies concerning the emissions causing cancer.

 

Also, how do you know how much power you are radiating?

You use a device called an FSM - http://electroschematics.com/405/field-strength-meter/

 

You use a device called an FSM - http://electroschematics.com/405/field-strength-meter/

Thanks! I'm assuming there is also a magnetic field meter, since this one measures the strength of electric field portion of the electromagnetic wave.

 

Thanks! I'm assuming there is also a magnetic field meter, since this one measures the strength of electric field portion of the electromagnetic wave.

http://www.amazon.com/E-L-F-Zone-E-L-F-Zone-Gaussmeter/dp/B000519WXA

Very popular for paranormal work too!

Real meter. http://www.magneticsciences.com/Bell5100-Gaussmeters.html

 

The actual emissions tests are done using an antenna in a anechoic chamber (or open area) at some given distance and with a given procedure. It's very hard to get repeatable results because everything matters.
The limits only apply in the exact configuration stated in the rules and if you test it in any other way the limits must change in some specific way.

Without an accredited test facility you won't know the exact answer, but you can get a very rough idea using your own tools. At the very least you need a spectrum analyzer...

Those linked gaussmeters are meant for high strength fields like from a permanent magnet or for residual magnetism. What you need to measure is very weak fields up to 1 GHz or more.

Practically speaking you just need to avoid interference. If beside your device the radio is clear, WiFi networks still work, cell phones work etc. then you know at least that you're not horrifically ruining the neighbourhood.

 

The MIT version was transparent biologically speaking, and was fairly high power levels. At high power any RF can cause some effects (mostly bad), which is one of the reasons I think they got away from RF and focused on magnetic coupling. I'm looking forward to a better explication from them.

 

Yeah me too. Their paper is just too mathematically involved. I want to know to know how they did this through magnetic coupling only. It's hard to say because in my experiment, the only way I think a magnetic field will dominate the electric field is to have an LC circuit oscillate back and forth at resonance, but this is how radio tuners work too. I can't figure out how to actually do this even though I think I may have figured it out, but not really. There will be RF radiation for sure, but how do you minimize this to almost zero??

 

I can't figure out how to actually do this even though I think I may have figured it out, but not really.

The guys at Toyota said the same thing about cars.

 

I can't figure out how to actually do this even though I think I may have figured it out, but not really.

So did the guys at BP (it isn't called British Petroleum, by the way, although the American news network seems to think so).

 

<snip>

Speaking of solar cells, their efficiencies are going to be taking some nice jumps in the near future, and they are even better than wireless. Keep up on the literature. One of my favorite sites is http://www.physorg.com/

Bill,
Speaking of physorg, have you seen the article they had on LED lighting that also doubles as a communication device??

http://www.physorg.com/news168623704.html

B. Morse

 

I hadn't seen that one, or thought of the application.

What I've been keeping an eye on is graphene, and superconductors.

There have been a series of quiet breakthroughs on superconductors, mostly theory. They are getting close to being able to reliably predict whether a material is a superconductor and under what conditions. Some materials temperatures go way up if they are stressed or put under specific pressures. The holy grail of room temperature is a long ways away, but it's looking more possible.