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Padraic
Special Collaborator
Honorary Collaborator
Joined: February 16 2006
Location: Pennsylvania
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Points: 31169
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Posted: April 24 2013 at 11:31 |
Dean wrote:
Padraic wrote:
OK, so thermal noise at 300 K is -204 dBW/Hz. I'll give you 1 kHz of bandwidth for transmission, so that gives us -174 dBW noise floor. So you have an SNR of 40 dB, a pretty whopping signal. |
Well, no - the SNR is zero - I suspect we're now at cross-purposes.
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You lost me there. -136 dBW - (-174 dBW) = 38 dB
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Dean
Special Collaborator
Retired Admin and Amateur Layabout
Joined: May 13 2007
Location: Europe
Status: Offline
Points: 37575
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Posted: April 24 2013 at 12:19 |
Padraic wrote:
Dean wrote:
Padraic wrote:
OK, so thermal noise at 300 K is -204 dBW/Hz. I'll give you 1 kHz of bandwidth for transmission, so that gives us -174 dBW noise floor. So you have an SNR of 40 dB, a pretty whopping signal. |
Well, no - the SNR is zero - I suspect we're now at cross-purposes.
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You lost me there. -136 dBW - (-174 dBW) = 38 dB |
The purpose of the exercises was to calculate the minimum transmitter power needed to achieve an SNR of zero at the receiver (with respect to the CMBR+Thermal Noise+switching and other spurious noises+Quasars and other assorted celestial noise sources) - if the back-calculation failed to do that then the transmitter output would be 38dB too big.
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The Doctor
Special Collaborator
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Joined: June 23 2005
Location: The Tardis
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Points: 8543
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Posted: April 24 2013 at 12:22 |
The SNR of the DWF less the function of the square-root of the PDQ plus the LOL to the power of the WTF must be less than -.37856352746352947563554756221 of AAAGGGGHHHHH!
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I can understand your anger at me, but what did the horse I rode in on ever do to you?
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Padraic
Special Collaborator
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Joined: February 16 2006
Location: Pennsylvania
Status: Offline
Points: 31169
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Posted: April 24 2013 at 12:23 |
Dean wrote:
Padraic wrote:
Dean wrote:
Padraic wrote:
OK, so thermal noise at 300 K is -204 dBW/Hz. I'll give you 1 kHz of bandwidth for transmission, so that gives us -174 dBW noise floor. So you have an SNR of 40 dB, a pretty whopping signal. |
Well, no - the SNR is zero - I suspect we're now at cross-purposes.
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You lost me there. -136 dBW - (-174 dBW) = 38 dB |
The purpose of the exercises was to calculate the minimum transmitter power needed to achieve an SNR of zero at the receiver (with respect to the CMBR+Thermal Noise+switching and other spurious noises+Quasars and other assorted celestial noise sources) - if the back-calculation failed to do that then the transmitter output would be 38dB too big. |
That's all I was getting at. I don't think we have any more quibbles.
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Dean
Special Collaborator
Retired Admin and Amateur Layabout
Joined: May 13 2007
Location: Europe
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Points: 37575
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Posted: April 24 2013 at 12:23 |
^^ see that, the silly bugger's completely lost without his sonic screwdriver.
Edited by Dean - April 24 2013 at 12:24
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Padraic
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Joined: February 16 2006
Location: Pennsylvania
Status: Offline
Points: 31169
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Posted: April 24 2013 at 12:24 |
The Doctor wrote:
LOL to the power of the WTF |
That's an accurate description of a lot of posts on this forum.
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The T
Special Collaborator
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Joined: October 16 2006
Location: FL, USA
Status: Offline
Points: 17493
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Posted: April 24 2013 at 12:31 |
I dispute your calculations.
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Dean
Special Collaborator
Retired Admin and Amateur Layabout
Joined: May 13 2007
Location: Europe
Status: Offline
Points: 37575
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Posted: April 24 2013 at 12:31 |
Padraic wrote:
Dean wrote:
The purpose of the exercises was to calculate the minimum transmitter power needed to achieve an SNR of zero at the receiver (with respect to the CMBR+Thermal Noise+switching and other spurious noises+Quasars and other assorted celestial noise sources) - if the back-calculation failed to do that then the transmitter output would be 38dB too big. |
That's all I was getting at. I don't think we have any more quibbles. |
Tell you what, I'll knock 4 noughts off the 240ZW (so that's now 24EW) and we'll call it a day.
...anyone got 10 quadrillion Duracel Ultra AA batteries?
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Dean
Special Collaborator
Retired Admin and Amateur Layabout
Joined: May 13 2007
Location: Europe
Status: Offline
Points: 37575
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Posted: April 24 2013 at 12:33 |
The T wrote:
I dispute your calculations. |
You have the floor my friend...
...we wait with baited breath.
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Padraic
Special Collaborator
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Joined: February 16 2006
Location: Pennsylvania
Status: Offline
Points: 31169
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Posted: April 24 2013 at 12:35 |
Dean wrote:
Padraic wrote:
Dean wrote:
The purpose of the exercises was to calculate the minimum transmitter power needed to achieve an SNR of zero at the receiver (with respect to the CMBR+Thermal Noise+switching and other spurious noises+Quasars and other assorted celestial noise sources) - if the back-calculation failed to do that then the transmitter output would be 38dB too big. |
That's all I was getting at. I don't think we have any more quibbles. |
Tell you what, I'll knock 4 noughts off the 240ZW (so that's now 24EW) and we'll call it a day.
...anyone got 10 quadrillion Duracel Ultra AA batteries? |
Yep - I have two little boys at home.
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stonebeard
Forum Senior Member
Joined: May 27 2005
Location: NE Indiana
Status: Offline
Points: 28057
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Posted: April 24 2013 at 13:46 |
There are UFOs. They are not driven by aliens. Most of them are probably weird natural phenomena and the rest are weird government projects. Aliens almost certainly exist, but there's no reason to believe we've been visited by them. They're not going to travel billions of light years to invert cattle, sex up rednecks, and do u-ies (spelling? It's a word that you say but never write...) in the sky. Let's get real folks. They'd either not intervene in earth's development (a la Prime Directive) or they'd make damn well sure they were known (Independence Day or Close Encounter).
That about covers it.
Edited by stonebeard - April 25 2013 at 13:04
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ArturdeLara
Forum Senior Member
Joined: April 06 2012
Location: Faro, Portugal
Status: Offline
Points: 124
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Posted: April 24 2013 at 15:28 |
stonebeard wrote:
There are UFOs. They are not driven by aliens. Most of them are probably weird natural phenomena and the rest are weird government projects. Aliens almost certainly exist, but there's no reason to believe we've been visited by them. They're not going to travel billions of light years to invert cattle, sex up redneck, and do u-ies (spelling? It's a word that you say but never write...) in the sky. Let's get real folks. They'd either not intervent in earth's development (a la Prime Directive) or they'd make damn well sure they were known (Independence Day or Close Encounter).
That about covers it. |
^ That awkward moment when you remember what the thread is about...
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"Those who are not shocked when they first come across Prog theory cannot possibly have understood it." - Niels Bohr
"If you think you understand Prog, you don't understand Prog." - Richard Feynman
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CPicard
Forum Senior Member
Joined: October 03 2008
Location: Là, sui monti.
Status: Offline
Points: 10841
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Posted: April 24 2013 at 15:44 |
^Yes, it's all about Unexpected Forumites Obsessions...
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Dean
Special Collaborator
Retired Admin and Amateur Layabout
Joined: May 13 2007
Location: Europe
Status: Offline
Points: 37575
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Posted: April 24 2013 at 16:25 |
ArturdeLara wrote:
stonebeard wrote:
There are UFOs. They are not driven by aliens. Most of them are probably weird natural phenomena and the rest are weird government projects. Aliens almost certainly exist, but there's no reason to believe we've been visited by them. They're not going to travel billions of light years to invert cattle, sex up redneck, and do u-ies (spelling? It's a word that you say but never write...) in the sky. Let's get real folks. They'd either not intervent in earth's development (a la Prime Directive) or they'd make damn well sure they were known (Independence Day or Close Encounter).
That about covers it. |
^ That awkward moment when you remember what the thread is about... |
Really, you find none of this relevant? You were the one who suggested this line of study:
ArturdeLara wrote:
Some possible ways for an alien civilization to detect us:
- Satellite and radio signals sent to space (for a sufficiently close civilization).
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I think Centauri Proxima counts as being "sufficiently close" don't you?
I cannot say whether there is a civilisation there, but I can pretend there is one.
I cannot say whether they have invented radio recievers, but I can pretend that they have.
You can mock all you like, but unless people like me actually do the mathematical calculations to prove one way or the other then everything that people guess and speculate and wish for in this thread will forever remain a guess, a speculation and a wasted wish. The maths could have proved that it was all very possible and all very achieveable - sadly it didn't - but until you do that calculation everything is all a fanciful fiction and a lot of hot air.
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dr wu23
Forum Senior Member
Joined: August 22 2010
Location: Indiana
Status: Offline
Points: 20642
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Posted: April 24 2013 at 16:57 |
ArturdeLara wrote:
stonebeard wrote:
There are UFOs. They are not driven by aliens. Most of them are probably weird natural phenomena and the rest are weird government projects. Aliens almost certainly exist, but there's no reason to believe we've been visited by them. They're not going to travel billions of light years to invert cattle, sex up redneck, and do u-ies (spelling? It's a word that you say but never write...) in the sky. Let's get real folks. They'd either not intervent in earth's development (a la Prime Directive) or they'd make damn well sure they were known (Independence Day or Close Encounter).
That about covers it. |
^ That awkward moment when you remember what the thread is about... |
LOL....yes, and I'm glad I started this thread since it obviously gave Dean something to do.
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One does nothing yet nothing is left undone. Haquin
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Dean
Special Collaborator
Retired Admin and Amateur Layabout
Joined: May 13 2007
Location: Europe
Status: Offline
Points: 37575
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Posted: April 24 2013 at 17:04 |
Oh, pardon me - the floor is yours...
...we wait with baited breath.
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dr wu23
Forum Senior Member
Joined: August 22 2010
Location: Indiana
Status: Offline
Points: 20642
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Posted: April 24 2013 at 17:29 |
There are certainly UFO's by definition; unidentified flying objects. The question is are any of them due to a non human presence. Some are undoutedly weird phenomena we might not yet understand and others covert govt projects and still others are merely misidents. I also think it's unlikely they would travel light years just to mutilate some cattle, buzz around in our skies, make crop circles, or abduct humans for some genetic agenda. As you mentioned if they have a prime directive ala Star Trek then they are doing a poor job of staying hidden and not interfering but then Kirk could never follow that damn directive either. Yet... credible people; police, military,etc including several astronauts, claim to have seen ufos that did not look like anything they could identify and some of these credible people believe ufos are alien in orign. Other credible people over the years have had not only sightings but close encounters with seemingly unkown beings. So are we then to assume they are all lying or just plain crazy or seeing things...? IMO it's naive to simply dismiss all of the sightings and events over the decades if not centuries with out a good investigation . Sadly no one has done this on a proper level so we are left with ufologists and others who with little funding have been unable to get very far. That's bad science. And the problem is that science due to academic politics and other reasons are simply afraid to tackle the subject due to the 'giggle and ridicule' factor. They don't want to lose their tenure...sad comment on science these days when no one cares enough to dig into an unknown phenomenon. It's easy to take the null hypothesis road and just dismiss it all as 'silliness' and people seeing things but then if we had looked the other way on many events in the past and those few brave souls hadn't bucked the prevailing system back then , which was one of relgious bias, we might still be living in the Dark Ages. I'm also skeptical about ufos being ET for some of the same reasons mentioned above as well as others, but I'm not skeptical that people have genuine weird experiences that imo are not just hallucination and misidents but interaction with something unknown. After weeding through all the noise and years of reading and talking to people who have had very strange experiences I believe there is a signal here. For me the question is what does this represent? An unknown phenomenon affecting human consciousness or an unknown sentience screwing with our consciousness or perhaps a new sociologica/psychological l phenomenon tied into human consciousness...? Saying it's all just loonies will get us about as far as those in the past who said rocks could not fall from the sky or man would never fly.
Edited by dr wu23 - April 24 2013 at 17:38
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One does nothing yet nothing is left undone. Haquin
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Dean
Special Collaborator
Retired Admin and Amateur Layabout
Joined: May 13 2007
Location: Europe
Status: Offline
Points: 37575
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Posted: April 24 2013 at 18:16 |
No one has said it is silliness or loony. Being sceptical just means questioning the evidence, not blindly dismissing it or blindly accepting it.
If you do not think those events that cannot be explained are extraterrestrial in origin but are some phenomenon messing with human consciousness then I've nothing to add here - once it becomes an affect on consciousness rather than a measurable physical event then I see no reason to look for external sources because we cannot quantify or measure the effect to determine an external cause so the problem cannot be addressed by the scientific method.
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The T
Special Collaborator
Honorary Collaborator
Joined: October 16 2006
Location: FL, USA
Status: Offline
Points: 17493
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Posted: April 24 2013 at 21:09 |
I dispute everything that has been said on this thread.
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The Doctor
Special Collaborator
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Joined: June 23 2005
Location: The Tardis
Status: Offline
Points: 8543
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Posted: April 24 2013 at 21:20 |
^I dispute that.
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I can understand your anger at me, but what did the horse I rode in on ever do to you?
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