How far can a radio signal go before it degrades to the point it is indestinguishable from background noise?

Question

I was just thinking about this because of an article about seti. If we or another life form were using a signal based on radio technology how long would it take before something degraded the radio waves so someone listening for them would not be able to recognise them as artificial in the first place?

Answer 1

We really don't have a precise answer to that. It all depends - on frequency and power output. Plus, the more technology advances, the more efficient we manage to make our radios, the "further" we can talk. Technically, our radio signals sent way back when radio was first invented will eventually reach the stars and still carry intelligible information - but by that time, we'll all be long gone. We're talking millions of years here...

Answer 2

If u start out with 10,000 Watts . How many dBm is that??well it is 70 dBm .
space loss for a 1000 miles is about 125dBm .
Every time u double the previous distance it would loose 3 dB . so whine u start talking about large distances it drops quick. The back ground noise if u are not pointing to a hot body like a star is about 60 db. U have no chance of getting there without a directional antenna which could help a little but where would u point it ? 1 Light year in front??
Good luck and don't forget that we are moving 15 deg. every hour.

Answer 3

I'm no expert, but in theory, I'm thinking ... even if a radio signal from outer space were degraded, SETI may still be able to recognize an intelligent "rhythm" in the message that would distinguish it from mere background noise. Even if a message was not understandable, the broadcasted sounds may be noted and isolated from ordinary random noise.

Answer 4

That would depend on several things like how focused is the beam, how storng is the signal, what type of signal i.e. analog or digital, ect ect.


The thoery in SETI is that the sending civilization has to be relatively close i.e. 100 ly or less because they would have to had atleaset reached our level of technology to produce a strong enough signal for us to detect within the last 100 years. We have really only been listening for the last 45 - 50 years.

Answer 5

In space, degradation, depending on where the signal was coming from and what it was passing by, would be much less pronounced than it is in terrestrial signals. Remember, space is a vacuum so the signal would not be subject to the effects of travelling through a medium(until it hit our planet's atmosphere, if that's where it's being read from), only the radiation and signals generated from large solar bodies like stars.

Answer 6

All other thing being equal, the distance increases as the radiated power increases, and also increases as the sensitivity of the receiver increases. Some of the other things that will influence the maximum distance are whether the transmitted beam is concentrated in one direction or not, whether the path from transmitter to receiver contains absorbing or scattering matter, whether or the receiving antenna concentrates its reception in one direction, and the type of modulation, that is, how efficiently is the data superimposed upon the radio signal.

Answer 7

like each and every radiation, radio waves be afflicted by the inverse sq. regulation. If the gap traveled is doubled then the sign potential is decreased to a minimum of one / 4. If the gap is extra desirable with the help of 10 then the potential is split with the help of one hundred. As you will locate the sign potential straight away disappears into the historic past noise of the Universe. complicated indicators like audio or video will on no account be readable after 5 lightyears.

Answer 8

Radio signal can be distinguished from noise(NOISE is present in all frequency range) depending on frequency. Radio signal die before reaching a point due to loss of amplitude(energy). If noise frequency is same as that of radio signal .. radio signal will get corrupted.

Answer 9

It depends on the equivalent radiated power at the transmitted end. We listen to signals with radio telescopes from sources billions of light years away

Answer 10

In theory radio waves should go on indefinitely.