Schwan

I was playing around with my tuner today, during what turned out to be a very boring day. In fact it was so boring, that I was listening to the radio noise, since the antenna was broken. And then, as it usually happens under these circumstances, I started thinking - what is it that I’m actually hearing? To be more specific - what is radio noise? I've tried looking it up on the net, but the closest I came to an answer is that its radio waves coming from either man made sources, or from natural phenomena. So does that mean that if I went to a very desolate place in the galaxy, and would hook my earphones to the tuner, I'd hear nothing? Or would there still be noise?

Pointless, I know. But still interesting.

the_marq

I am pretty sure you would hear background noise anywhere in the known universe. As I understand it most stars give off some sort of radio signal that can be picked up by a tuner, that's how radio telescopes (like in the Jodi Foster movie "Contact") work.

But I'm no expert.

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irseg

The radio's gain control is maxed out trying to tune into a non-existant signal. When this happens you hear electrical noise from the radio itself, along with random stray radio waves. Those waves are both manmade and naturally occurring (you've probably heard a pop in the radio from a lightning strike, for instance).

Based on that I'd think if you tuned in from a desolate place in the galaxy, you'd still hear static, just possibly less of it due to the lack of interference from manmade sources aside from the radio itself.

Mephisto2

You hear a mixture of "noise" generated by the radio itself, as irseg states but also some Cosmic Backround Radiation (depending upon the sensitivity of the radio). This is, of course, not discernable to the normal ear as it it totally swamped by the "white noise"; only with very sensitive detectors and complex filters could you really hear the CBR. Check out http://csep10.phys.utk.edu/astr162/l...ology/cbr.html

As an aside, you also quite often can hear repetitive blips, squeeks and yawks. Not so common any more, but still easy enough to find. These are mostly a holdover from the Cold War when both NATO and the Warsaw Block used coded rapid radio signals to communicate with their agents, vessels and subs around the world. There's also a lot of standard low-level military and civilian traffic out there that sounds like noise.

All quite interesting in a geeky kind of way.


Mr Mephisto

flat5

the above is only for Amplitude Modulation detection.

Frequency Modulation detection is a very different noise from a tuner.
I think it's random and completely generated in the tuner itself.
Not sure at all, just guessing.

Remember, he said no antenna. well, broken.

the420star

antenna broken means very little.... a fraction of an antenna can recive signals, it just becomes how well its does it. There is a great deal of noise out there... if you notice raido stations are seperated by 2mhz i think, that is b/c none of the radio stations really put out their signal on exactly like 90.5 fm, its reall like 90.4-90.6. so you end up with bits and pieces of randomly generated noise in the gaps. That is the static and the other noise you here. as for the noise in the circuit, possible but not so likly, your radio employs numersous filters that are able to elminate the majority of that noise as well as other noise.

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Charlatan

Some of the sounds you are hearing were made at the dawn of time...



...if you listen you listen real close you can hear God saying, "Jesus! Stop playing with Adam and come in for supper!"

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Schwan

Let my clarify the antena thing. It's not plugged in. That's the whole issue with it. However, the static noise I hear without the antena doesn't seem to differ from the noise I hear when it's plugged in, but no station is set. I came up with the problem when, after a long day, I just layed on the bed and listened to the noise, and tried to make something out of it. You know, one of those days.

the420star

like i said... in or out really not a huge deal for reciving noise.... antenna's are classified by what fraction of a wavelength they are. So that place where the antenna plugs in, as well as the wire from the port to the board antenna, traces on the board antenna... lots of stuff to pick up noise. i dunno if that explains it more, keep asking more if you need more explination, i am an EE and am looking to specialize in Radio Frequency Design. But like i said, if i am not making sense let me know, i do that a lot.

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Schwan

Great! In that case the question is how far is the noise being picked up from? Some people said that it's the onboard electronics, others said that it's either stuff close by, or natural phennomenae, like thunder. Still, others said that the noise is generated by the whole universe, distant planets, and so on. I was wondering if the noise I'm hearing might be something coming from space .

wolf

LMAO

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flat5

no point saying what I put here. It only had meaning for me.
So, it's gone.

chateau_margaux

You'd hear noise everywhere, as the tuner itself would be searching and finding nothing. Does a tree in the forest with noone around make a sound when it falls? Yes, it creates the 'noise' for the sound, so if a tuner was positioned correctly, it could interpret the soudnd. Me personally, I think you hear the aliens when you hear radio noise

Schwan

I kind of suspect that's the case.