Get Some Perspective

[N0WVA]

There are between 10 sextillion and 1 septillion stars in the Universe.

http://www.universetoday.com/guide-t...ow-many-stars/

Our problems seem rather insignificant in the grand scheme of things. And the inability to comprehend what is out there really makes human kind look they just crawled out of a slime pit.

If there is life out there ( quite sure there is) and they know how to control time, then we surely are the dumb ones on the block. Probably the only thing saving us from being wasted by any other intellegence is that we are hidden within the sheer numbers of stars.

[W4HAY]

Or they figure we're not worth the effort!

[AF6LJ]

Contrary to what the SETI people would have you think; radio signals don't travel very far.

Someone please correct me if I am wrong but on UHF the path loss to the moon and back is 140DB.

Every time you double the distance the path loss decreases in power by six DB or voltage by twelve DB take your pick. I have heard that our radio signals get buried in the 3 degree K background noise of space somewhere between two and three light years out.

The HF signals leave the atmosphere with much attenuation, leaving them with less distance to travel before they fade into the noise. The only way to get a signal out of the noise is to know the modulation scheme and where to look, you weak signal guys know that.

We have been transmiting analogue voice signals for just over a hundred years, CW for something close to (umm) 115 years give or take.

The nearest star is 4.3 light years out almost double the distance our radio signals would be detectable, they would be six DB or so below the three degree K background noise of space. Not knowing the modulation we use would make those signals difficult if not impossible to recover any intelligence from.

To add insult to injury;
the nearest star is believed to have no life bearing planets. Furthermore we as a civiliation have over time sent fewer and fewer high power VHF and UHF signals into space since we rely on satellite communications more and more which sends low power signals toward the planet and not into space. On top of all that, we use digital encryption and spread spectrum not simple AM or FM or even simple FSK schemes to convay information anymore.

The odds are very much against us ever being heard.
The odds of us hearing anybody else are also very much against us. We will have to look for life by other means.

[G8ADD]

Contrary to what the SETI people would have you think; radio signals don't travel very far.

Someone please correct me if I am wrong but on UHF the path loss to the moon and back is 140DB.

Every time you double the distance the path loss decreases in power by six DB or voltage by twelve DB take your pick. I have heard that our radio signals get buried in the 3 degree K background noise of space somewhere between two and three light years out.

The HF signals leave the atmosphere with much attenuation, leaving them with less distance to travel before they fade into the noise. The only way to get a signal out of the noise is to know the modulation scheme and where to look, you weak signal guys know that.

We have been transmiting analogue voice signals for just over a hundred years, CW for something close to (umm) 115 years give or take.

The nearest star is 4.3 light years out almost double the distance our radio signals would be detectable, they would be six DB or so below the three degree K background noise of space. Not knowing the modulation we use would make those signals difficult if not impossible to recover any intelligence from.

To add insult to injury;
the nearest star is believed to have no life bearing planets. Furthermore we as a civiliation have over time sent fewer and fewer high power VHF and UHF signals into space since we rely on satellite communications more and more which sends low power signals toward the planet and not into space. On top of all that, we use digital encryption and spread spectrum not simple AM or FM or even simple FSK schemes to convay information anymore.

The odds are very much against us ever being heard.
The odds of us hearing anybody else are also very much against us. We will have to look for life by other means.

Don't forget that the EME path loss includes reflection losses from the lunar surface! Current techniques permit us to detect fractional variations in the 3K background. HF attenuation depends on many factors including the state of the ionosphere and the horizon angle, and the distance at which they become undetectable in the 3K background (to our current technology) is frequency dependant. So I think you are overly pessimistic. However, the chances of a technological civilisation within the volume of space that our signals have travelled are quite slight...and I think it would be very sensible to detect them and learn as much as we can about them before we considered allowing them to detect us! Remember the conclusion of A. C. Clarkes short story "The Sentinal", the precursor of "2001".

73

Brian G8ADD

[AB8MA]

Someone please correct me if I am wrong but on UHF the path loss to the moon and back is 140DB.

Try long path?

[N0SYA]

LOL!!!!!!!!!!!!!!!1111111111111!!!!!!!!!!!!!!!!!ON E!

[WB3JLA]

We put a 45 RPM gold record on VOYGER

I hope we sent the adapter

[WB1HJS]

We're going to have to send a new record with a diagram of an HDTV packet since we did away with analog.

[AG3Y]

Isn't it funny how fast technology changes ? ? ?

[AF6LJ]

Isn't it funny how fast technology changes ? ? ?

I would bet how technology changes here is closer to the rule than the exception.


G8ADD;
My view may be overly pessimistic I do remember the last time Pioneer Eleven was contacted it took several large dishes in the western hemisphere to capture enough signal from the twenty watt transmitter running into an S-Band dish. (I worked for the place that built the power amplifiers three decades ago) to decode telemetry.

If other civilizations follow a similar path of evolution It's reasonable to expect the window of time radio signals will be strong enough to be heard is short only a hundred years or so, a very short time indeed.