Strong radio signal at 1420 MHZR eminating from a location off of the planet!, page 2
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reply posted on 4-5-2004 @ 01:08 AM by Durandal
Originally posted by EmbryonicEssence
Durandal, I just meant: Originating, located, or occurring outside Earth or its atmosphere - not the intelligent extraterrestrial life part. :-D

I'm curious though, do you know of how many times there has been a true repeating pattern, that maybe lasted just a few seconds, and was truly extra-terrestrial in origin (one that could have been artificially made)?


EE, I'm not sure that any organization has encountered a signal that has had those characteristics, at least none have been released publically. But there are some promising signals...

from www.setileague.org...
Modern SETI was born in 1959, with the publication in Nature of a short paper by Cocconi and Morrison [3] proposing a search of nearby Sun-like stars, near the 1420 MHz neutral hydrogen frequency, for artificially generated signals. Unbeknownst to the authors, even as they wrote their paper Frank Drake was preparing to perform the very experiment which they were proposing. Project Ozma searched only two stars, at that single frequency, for two months during the summer of 1960. During the succeeding years, several dozen other SETI experiments have been performed, many still concentrating on the hydrogen line as a likely frequency for interstellar communications.

The longest running of these is the Ohio State sky survey, which has been continuously operational since 1973. It was the Ohio State Radio Observatory which on August 15, 1977 detected the most tantalizing and promising candidate signal to date, the so-called "Wow!" signal. The computer printout of this historic signal is shown in Figure 1.

The "Wow! received its name from the marginal note on the computer printout, penned by SETI volunteer Dr. Jerry Ehman. "I came across the strangest signal I had ever seen, and immediately scribbled 'Wow!' next to it," Ehman explained. "At first, I thought it was an earth signal reflected from space debris, but after I studied it further, I found that couldn't be the case." [4]

The letters and numbers in the printout are today widely misinterpreted as a message. "What does the progression 6EQUJ5 actually stand for?" asked one SETI enthusiast. "A sequence in need of completion? A matrix in need of expanding? A computer malfunction? The ASCII equivalent to a binary code?" [5]

Let me emphasize that the "Wow!" sequence itself is not a message. What was received appeared to be a CW (unmodulated) signal. The numbers and letters in the much-reproduced computer printout are merely a time-series representation of the signal amplitude, as received at the Big Ear radiotelescope. Specifically, the symbols represent the number of standard deviations by which the received signal exceeded average background noise, on a scale of 0 to 35. So a 0 means no stronger than background noise, 1 is one sigma above noise, 9 means nine sigma above noise, an A would be ten units, and U (the strongest peak of the actual signal) is 30 standard deviations above the mean background noise in the receiver. If you graph the sequence as amplitude values over time you get roughly a Gaussian distribution, consistent with the antenna pattern of the Big Ear in drift-scan mode. The data set depicts signal amplitude over both frequency and time.

Figure 2 shows just such a graph of the output of the Ohio State 50-channel receiver during the transit through the antenna pattern of the "Wow!" source. Time is plotted horizontally, amplitude vertically, and frequency in the depth axis. The time increments are twelve seconds per sample. Each of the channels is 10 kHz wide; thus, a half MHz surrounding the hydrogen line is depicted. Note that the signal rises almost 15 dB above the background noise, in a single channel, then falls back into the noise, its amplitude pattern exactly coinciding with the known beamwidth pattern of the dish (including its feed-induced skew, and coma sidelobes).

From the "Wow!" signal's temporal correspondence to the antenna pattern, we know that its source was moving with the background stars. From its Doppler shift signature (the local oscillator of the receiver was being chirped at a rate which corresponds to the Earth's motion with respect to the Galactic center of rest) we can eliminate terrestrial interference, aircraft or spacecraft from consideration. The antenna coordinates indicated that the signal was coming from no known nearby sun-like star, though at any time, in any direction, the antenna pattern encompasses on average about half a dozen distant stars. Most significantly, though over a hundred follow-on studies of the same region of the sky were performed, from several different radio observatories, the signal never repeated. [6]

Of course, it should not have. Consider that the Big Ear radiotelescope at the Ohio State Radio Observatory is extremely narrow in beamwidth, viewing just one part in a million of the sky at a given time. That means if you are listening on exactly the right frequency, at exactly the instant when The Call arrives, there's still a 99.9999% chance you'll be pointed the wrong way. And if we imagine that the "Wow!" signal emanated from a similar high gain antenna, which (let us assume) illuminates only one millionth of the sky, what are the chances the two antennas will be pointed at each other at the same time? That's easy, says the statistician: (1e-6) squared equals (1e-12).

But wait, if we know the direction from which the signal emanated, and concentrate our antennas there, we've removed one factor of (1e-6), and we're back to million-to-one odds. Even still, we've only looked in that direction for a total of a few tens of hours. Not only have we not yet scratched the surface, we haven't even felt the itch.


SETI@home's Best Gaussians
Candidate skymap

Hope this helps,

-Durandal





[Edited on 4-5-2004 by Durandal]


reply posted on 4-5-2004 @ 09:38 AM by Genya
First off, sorry to (once again) be late for the party here!! It is all related to our time difference and - yipes! - work...

Second, thanx to pantha who flagged this thread to me by U2U, which I was delighted to receive. Thanx p!!

I've read all the material in the thread here and have tried to find definitive information on the source of the story (nothing new there - I'm sure you have all done the same too).

SETI@home isn't carrying this story on their home page at present, although as others have mentioned this might be because they are following their protocols (getting confirmation of the signal, trying to ensure it's not generated "locally", etc) before they went public with an announcement?

Simialrly, a search of keywords like SETI signals, etc, on Google news, didn't present this story either.

The "best fit" I could get to the source of this story is from

www.faqs.org...

and then this

groups.google.com...

and then (3 May 2004 1428 Mhz Loud Noise every night (19 articles) P. Backus this

groups.google.com.../groups%3Fgroup%3Dsci.a stro.seti

The story *seems* to be based on these comments (from the above article):

"From: Perseus@hol.gr (Perseus@hol.gr)
Subject: 1428 Mhz Loud Noise every night

Newsgroups: sci.astro.seti
Date: 2004-04-27 18:44:22 PST

Every night i hear a loud noise at 1428mhz all modes but sounds better on WAM. It looks like some digital mode. It fades litle by litle at morning .10-11 o,clock you hear nothing.

What is this noise on H freq ?"

There are then various suggestions as to the possible source, ranging from cpu interefence ie perhaps an harmonic of a cpu being driven at 133Mhz etc, to GTS/ ISS uplink frequencies, although both these ideas appear to have been discounted.

So, I've got no idea what this signal might be: unfortunately, my transceiver only operates up to UHF, so I'm unable to verify whether this signal is audible in this part of the UK or not. Perhaps somebody else has access to a suitable receiver - if so, please tell us about it here!!

One thing I am sceptical about (with regards to the possibility of this signal coming from deep space) is the sheer intensity of the reported signal, which is being quoted as being

"No it is not ISS or low orbit satellite because the signal is very stable for many hours and very strong 9++."

That means the signal is extremely strong and sounds (to me) rather like localised interference rather than a signal that was transmitted several light years away (or even from a "mothership" unless this was in very close proximity to Earth).

I am concerned, however, that "the signal is very stable for many hours" because, as the Earth rotates, *if* the transmitter was external to the Earth, then I would expect the source to "appear" to move with the sky (just as the Sun appears to rise, culminate and set over the course of a nominal 12 hours). That it appears to be "stable" suggests (to me) that the transmitter is Earth-based (or in geo-synchronous orbit) rather than "out there" somewhere.

So, sorry, I've got no further information on this. I guess we will have to wait to see how this story develops (which it might be doing even as I write this, of course!!)

Certainly very interesting - thanx for "making my day" so far!!
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