EM radiation

For an experiment, I want to be able to radiate a sample with
electromagnetic radiation that I am able to vary in frequency over as
wide a range as possible. I don't even know what a device that can do
this is called- can someone please help point me in the right
direction?

-Kevin

 

** Google TROLL Alert !

** Straight up.

Just ask a really cool guy named Scotty to " beam " you.




...... Phil

 

The fields, either magnetic or electrostatic, will vary with the radiation device, such
as antenna or coil. Antenna would need an RF power amp in the range you need.
I used to have a generic power amplifier used to test ultrasonic up to about 10 Mhz.
You feed the power amp with an RF signal generator. Low frequencies are best radiated
with a coil.

greg

 

You need an "RF Generator" or "Service Monitor".

Here are a link I Googled using "IFR" to get you started, though this
is not exhaustive by any means... (IFR is a manufacturer, and I've
used them before with good results.)

http://www.econ2way.com/service-monitors.htm

This gear probably does more than you need, and they are expensive.
You may be able to lease one. Or, you can try around two-way radio
repair shops in your area and try making friends with one of the
techs.??

HP, and others, also make stand-alone RF Generators.
You will need to know what frequency range you are interested in.
You will also need to know how much RF power you wish to generate, and
whether or not it exceeds the capabilities of the above.

Then depending on what you intend to do, you may need to design a
calibrated "antenna" system so you can control the RF transfer to your
device under test. -mpm

 

I assume you meant radio-frequency.
If otherwise, my post above may not be what you want?

 

That was very helpful- thanks a lot!

 

Hmm. A signal generator into a loop antenna? of course, you didn't
specify how much radiated power you were looking for?

 

If you really want a wide RF range you might try a spark gap
transmitter: http://en.wikipedia.org/wiki/Spark-gap_transmitter
Of course you would probably interfere with every radio and TV
for miles around.

[8~{} Uncle Monster

 

And don't forget the sun as a source! At
least IR to gamma.

Chuck

 

Actually, the bottom end is much lower than that. It radiates a lot
of 0.000125Hz

 

If my math is right, that's over 2 hours a cycle.
So I guess you really can get sunburned with just a quarter-
wave....

-mpm

 

How does it manage that? An antenna even as big as the
orbit of Earth is still small compared to that wavelength
(of 2.4 billion kilometers). The Sun is positively tiny
compared to that wavelength.

 

Carcinotron.

 

Electromagnetic radiation can be radio, microwave, infrared,
visible light, ultraviolet, soft to hard X-rays, etc.

The 'radio' range is about 200 kHz to 1 gHz - frequency difference
10**9
while the 'visible light ' range is about 10**18 hertz... so
a pinhole and prism on a sunny day gives a pretty wide frequency
variation.

For 'as wide a range as possible' there are synchrotron sources of
hard X-rays that can give 10**22 Hz frequency range.

 

As I understand it: The sun sends out streams of charged particles.
This makes it appear much larger than its obvious size and there is a
lot of horsepower available to drive the poor radiator.

 

Absolute frequency yes, but relative, no. Sunlight covers a little over one
octave, if that (~400-1000nm). The sun puts out little IR (since its
black-body peak is in the visible range), and the atmosphere filters the UV
tail.

Tim

 

a spinning magnet radiates

Bye.
Jasen

 

When you say "little IR", what are you comparing it with? Blackbody
curves for different temperatures never cross--heating up an object
makes it glow more brightly at all wavelengths. Thus the Sun is a much
brighter infrared source than any terrestrial object, other than a laser.

Cheers,

Phil Hobbs

 

Other blackbody radiators, normalized by peak output.

As I recall, they do. The sun emits very little microwave radiation, while
the cosmic background temperature gives off copious amounts.

(I suppose it might be possible to place microwave detectors on the sun
(nevermind the physical difficulty of diodes operating at 7000K, but that's
just an engineering problem), collecting the few picowatts of CBR that pass
along, relaying that power back to a cold sink which thereby radiates more
microwave radiation. Likewise, the cold sink transforms the visible
radiation from the detector into additional microwave radiation.

It's an interesting thought, but I'm sure that, if I ran the numbers, I'd
discover that it doesn't come out over unity, which is how it ought to be,
after all.)

Infrared perhaps, but not far IR or microwave.

Consider: if this were true, then celestial x-ray and gamma sources would be
visible on telescopes (assuming there is a direct line of sight, which for
energetic radiation, need not be). Many radio and x-ray sources are only
visible due to visible-spectrum matter, as I recall.

Tim

 

http://web.njit.edu/~dgary/728/Lecture11.html
Radio Astronomy Lecture Number 11

http://www-xray.ast.cam.ac.uk/xray_introduction/History.html
Introduction to X-ray Astronomy