The Myth of Radio Spectrum Interference

Selanit writes "Just came across a fascinating article on Salon about a technologist who claims that there is no such thing as "interference" in the radio spectrum. He argues that interference is a symptom of inadequate equipment, not a fact of nature, and that with improved transceivers we could open the spectrum up to high-quality broadcasts by anyone. Reference is made to the GNU Radio Project. Neat stuff." We've posted other stories about this. I wonder if the "color" meme will catch on.

Comments

There are more sensitive radio receivers out there

[tjwhaynes]

and they are known as radio telescopes!

Radio Astronomers have a hard enough time keeping the important wavebands free of interference without the radio spectrum being unregulated. Lots of useful, hard science is being done by the radio telescopes around the world observing the machinations of galaxies out in the distant universe. One of the key problems is that these signals are amazingly faint. The standard unit used in radio measurements is the Jansky - thats 10^(-26) Joules per second per square metre - which should give you some indication as to how faint. Lift that coke can off the floor onto the table and you've just used up more energy than has been received from distant galaxies by ALL the radio telescopes on the surface of the planet.

Terestrial radio transmitters are so many orders of magnitude stronger than these signals that any sideband transmissions even 90db below peak transmission still totally swamps the surrounding spectrum. And very few transmitters are truely 'perfect'. It's not as though a transmitter broadcasting at frequency X with HWHM waveband Y can't be detected at X +/- 8 Y. Yes - better quality receivers allow you to separate out signals at close frequencies, but a very strong signal next to a very weak signal will drown out it's neighbours.

Cheers,

Toby haynes