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Speed of Radiowaves

J

jongyoo

Member
I was wondering if the advancement of electrical technology has actually increased the speed of radiowaves to send information. Being an electrical engineering student I know that the propagation of EM waves are C but I was wondering if there was anything that actually changed this speed.

And I remember my chem II teacher in high school telling me something about slowing down the speed of light to 18mph or something through a certain type of cooled glass. Any ideas? Thanks
 
Speed of light (EM waves) change depending on the medium it is in. The maximum it can ever be is c, and that is in free space. What you mentioned about slowing light down to 18mph is through shining light through very cold sodium gas IIRC (please correct me if I'm wrong). There is no advancement that can change that constant AFAIK. Unless you change the method of sending the information itself, you will be limited to c ...always.
 
C is a universally defined constant, no advances in science can change that

Some one had been claiming c may have changed since the creation of universe but no one can ever prove it
 
Originally posted by: jongyoo
I was wondering if the advancement of electrical technology has actually increased the speed of radiowaves...I know that the propagation of EM waves are C..... Being an electrical engineering student
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:Q
 
They increased the usable bandwidth. Considering that usually the internet bandwidth is referred as speed, I still found your ignorance disturbing
 
Originally posted by: jagec
Originally posted by: jongyoo
I was wondering if the advancement of electrical technology has actually increased the speed of radiowaves...I know that the propagation of EM waves are C..... Being an electrical engineering student
Click to expand...

:Q
Click to expand...

Perhaps a freshman engineering student who hasn't taken E&M yet?
 
It sounds like the question is really about the effective speed of electronic devices, rather than the speed of the radiowaves themselves. Everyone has commented that the speed of light is relatively constant (ha, Einstein joke) in a given medium... but the problem with electronics has been Moore's Law Vs The Laws of the Universe.

Back when I was in Devices Physics... the fastest CPU ran at 300Mhz, and everyone was worried that silicon just couldn't be pushed any faster at those voltages or with any current. The little transistors would never be able to switch that fast, or recover afterward before the next signal. Clearly we have gotten around that, but it's by more "smoke & mirrors" than actual MHz.

We use multiple pipelines, and staged instruction sets to act as an group of assembly lines, rather than a single line doing all of the work. Shrinking the CPU die size has also had a big effect by effectively shortening the length an electrical signal has to travel. There's all kinds of little tricks they have used to eek out more "MHz" every year... but there is a limit to silicon. That's why AMD uses the PR rating. Their chips running at 2600Mhz and a 9 stage line are just as fast as Intels running at 3400MHz with a 22 stage line. It more mechanical design than actual science.

Drawing this trainwreck to a close... No, scientists have not make waves move faster through Silicon. However, the extremely-deadly-to-produce Gallium arsenide used in LEDs is a whole different story, as signals do move (a little) faster in it (up to 300TeraHz). Could be the way of the future, but I doubt it. We'll invent something totally new by then.
 
Originally posted by: MelkorTDL
WAIT!!!! There's a new scientific BREAKTHRU that actually DOES increase the speed of radio waves through a medium (like air)!!

http://j-walk.com/other/wifispray
Click to expand...


If you're not 100% satisfied, return the unopened bottle
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Disclaimers

WiFi Speed Spray? is safe and effective when used as directed. However, the product is known to the State of California to cause cancer; developmental toxicity; and/or male pattern baldness. For outdoor use only. Do not use near electrical appliances. WiFi Speed Spray? should not be used in the presence of pregnant women, women who have been pregnant, or women who may some day become pregnant. Keep away from children and household pets (especially birds). Do not take internally. If a persistent cough or partial paralysis develops, consult a physician,
Click to expand...
Made in Malaysia, by Malaysians. Not intended for use by Malaysians
Click to expand...
Celebrity Endorsement

"I've been using this stuff since 1948"
Click to expand...

some pretty funny stuff.
 
Originally posted by: jongyoo
I was wondering if the advancement of electrical technology has actually increased the speed of radiowaves to send information. Being an electrical engineering student I know that the propagation of EM waves are C but I was wondering if there was anything that actually changed this speed.

And I remember my chem II teacher in high school telling me something about slowing down the speed of light to 18mph or something through a certain type of cooled glass. Any ideas? Thanks
Click to expand...

Whatchoo talking about Willis?
 
Originally posted by: MelkorTDL
WAIT!!!! There's a new scientific BREAKTHRU that actually DOES increase the speed of radio waves through a medium (like air)!!

http://j-walk.com/other/wifispray
Click to expand...

"Compatible with Windows and most versions of Linux."
😛
 
Originally posted by: leha
(to teh original post) You messing up two different quantities. There are the speed of light and a group velocity ( the later most often refered as speed of light ). The light speed is constant and a group velocity varies in different media. See http://en.wikipedia.org/wiki/Group_velocity
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With a gazillion HS physics teachers (Dr. Pizza excepted) telling their students that C is medium dependant - good luck.

 
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