Radio waves vs light waves

You kept it out of technobabble, but you kept it far from the truth.

Would you mind not stepping into an argument where you have not a clue as to the
answer?

Jim

Buff5200
shared these priceless pearls of wisdom:

-
-
-Ok, I'll try to keep it simple and free from techno babble:


Jim Weir (A&P/IA, CFI, & other good alphabet soup)
VP Eng RST Pres. Cyberchapter EAA Tech. Counselor
http://www.rst-engr.com

Jim Weir wrote in message . ..
You kept it out of technobabble, but you kept it far from the truth.

So how about explaining what was untruthful, rather than offering a
drive-by shooting critique. I read these posts to get smarter not as
a forum for putdowns.

"Tim Witt" wrote in message
om...
Jim Weir wrote in message
. ..
You kept it out of technobabble, but you kept it far from the truth.

So how about explaining what was untruthful, rather than offering a
drive-by shooting critique. I read these posts to get smarter not as
a forum for putdowns.

Mr. Weir gets offended when people post over his head. It is only his way
of expressing his displeasure.

Weir is a big asset to small GA, so he can pretty much express his
displeasure as he pleases.

"Jay Honeck" wrote in message news:%

....Radio waves are the same as light
waves, except they're not in the visible spectrum, right?

.....I wondered aloud if the lens in my
eye was at that moment focusing powerful radio waves onto my retina.

[fade theme].......You're traveling through another dimension....a dimension not only of sight and sound but of mind....

Jay

The wavelength of a VOR transmission is about 8ft long. The wavelength
of a visbile light is about 0.5 micrometer. You can fit thousands of
wavelengths inside the pupil of your eye, but you cannot fit even a
small fraction of a radio wave. For a lens to behave like a lens, its
size must be much larger than a wavelength. If it is smaller, only a
tiny fraction of a wavelength will get through. It's like trying to
squeeze a large object through a small hole. Insteading of focusing,
it simply scatters (diffracts).

If you are concerned about a VOR, consider that commercial radio and
TV stations transmit at much higher power levels. Think about that
next time you stare at a TV tower :-)




"Jay Honeck" wrote in message news:%uRYb.353608$na.522124@attbi_s04...
Okay, here's a weird one for the group: Radio waves are the same as light
waves, except they're not in the visible spectrum, right?

Here's why it matters: As we were departing from Muscatine, IA today (a
beautiful day to fly in the Midwest, BTW -- clear and warm) after a great
lunch, my gaze fell on their on-field VOR transmitter. Focusing closely on
the "Hershey's Kiss"-shaped structure (with my new glasses -- wow, what a
difference a new prescription makes!), I wondered aloud if the lens in my
eye was at that moment focusing powerful radio waves onto my retina.

Mary, a scientist with a strong physics background, was not sure if radio
waves behaved the same as light waves.

I've never heard of anyone frying their retinas by looking at a radio
transmitter, but this begs the question: Can the lens in your eye focus
radio waves?

If not, why not?

No, the cornea is too small in terms of wavelength to effectively refract,
focus radio waves... Plus there is the issue of the low refractive index
of the lens at radio frequencies, even were it were large enough...

That's not to say that radio waves cannot cause heating damage to the
tissues of the cornea and the retina, even if unfocused, as they pass
through your body...
The millimeter wavelengths - including your microwave oven - can certainly
heat damage body tissues, ask any hotdog...
But a discussion of that has to include the wavelengths involved, the
intensity of the radio field at that point in space, the temporal length of
exposure, etc... Too big a topic for this type of forum, but radar
technicians have accidently had eye damage from looking into a working
antenna...

Interestingly, or maybe not ham radio operators have to fill out an
engineering form that quantifies the level of exposure to radiation of
people near to their antennas and file it with the government... If you
have more than a passing interest in that item let me know and I'll refer
you to the relevant literature...

cheers ... denny

"Jay Honeck" wrote I wondered aloud if the lens
in my
eye was at that moment focusing powerful radio waves onto my retina.

radar technicians have accidently had eye damage from looking into a working
antenna...


or even looking away from... as proximity is the only important factor, not
orientation.

Jose


--
(for Email, make the obvious changes in my address)

Now you are getting technical... I will be forced to reorient your wave
guide mode discharge if you keep it up...
denny
"Teacherjh" wrote in message
...

radar technicians have accidently had eye damage from looking into a
working
antenna...


or even looking away from... as proximity is the only important factor,
not
orientation.

Jose


--
(for Email, make the obvious changes in my address)

On Wed, 18 Feb 2004 at 22:16:27 in message
%uRYb.353608$na.522124@attbi_s04, Jay Honeck
wrote:

I've never heard of anyone frying their retinas by looking at a radio
transmitter, but this begs the question: Can the lens in your eye focus
radio waves?

No, Firstly the transparency of materials to EM radiation varies with
frequency. Secondly the wavelength of the transmissions is very large
compared to the lens in your eye. A 3GHz transmission has a wavelength
of 10cm.Red light, the longest wavelength of visible light has a
wavelength of about 1 micron (! millionth of a metre).

E&OE
--
David CL Francis

The below answer is from the top of my knowledge. I haven't especially
studied physics, but I had some interest in the field at school, that is
about 10 years ago.


Jay Honeck wrote:

Okay, here's a weird one for the group: Radio waves are the same as light
waves, except they're not in the visible spectrum, right?

Wrong. Light is made of of particules which move in an approximate
straight line. I say approximate, because it's not going perfectly
straight. Light going perfectly straight is called 'laser'. The normal
light is not going perfectly straight, that is why you can see a large
area on the highway during the night.

Radio waves is electricity. Remember the atoms drawing from school? The
center of the atom (nucleus) is made of protons (positive charge) and
neutrons (neutral charge), and electrons (negative charge) circle around
the nucleus. To produce electricity you make the electrons to circle
faster than usual. When electrons are going fast enough they will leave
their nucleus and hit the lectrons of the next atoms, replacing it.
Electricity is the form of energy caused by this electrons activity.
When you understand the basic of electricity (what I stated was the very
basic, the reality is clearly more complex and beyond my understanding)
it becomes obvious that electricity doesn't go straight, but instead in
any direction, as long as the matter can handle it (that is, you can
lock electricity within a copper wire because the surrending matter is
not compatible atomic-wise). For radio waves you simply emit electric
signal directly into the air. Unlike for electricity used as power,
electricity used as radio waves is very light (powerless) but very
controled (the frequency must be very precise for the receptor to be
able to reproduce the original signal).


Here's why it matters: As we were departing from Muscatine, IA today (a
beautiful day to fly in the Midwest, BTW -- clear and warm) after a great
lunch, my gaze fell on their on-field VOR transmitter. Focusing closely on
the "Hershey's Kiss"-shaped structure (with my new glasses -- wow, what a
difference a new prescription makes!), I wondered aloud if the lens in my
eye was at that moment focusing powerful radio waves onto my retina.

I wouldn't think that is the case. Lens are designed to focus the light
in a particular way (to compensate for your eyes lacking at doing it as
it should be), and I doubt this would have any effect on radio waves at all.


Mary, a scientist with a strong physics background, was not sure if radio
waves behaved the same as light waves.

I've never heard of anyone frying their retinas by looking at a radio
transmitter, but this begs the question: Can the lens in your eye focus
radio waves?

If not, why not?

Have you even lit a fire with your glasses, concentration light from the
sun onto a sheet of paper? I am not quite sure, but I think this is not
possible. Unlike a magnifying glass, your glasses lens are designed to
focus the light, not concentrate it. I don't wear glasses; when you
stare at the sun do you think it burns you eyes harder with glasses than
without it?

Eventhoug radio waves behave like light, I doubt the glasses wouldn't
have any effect, as I don't think it concentrate the waves, just focus
it, and also because radio waves are very light.

Again I am no physicians. Just my 2¢ here.

Tom