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Most of terrestrial communications on VHF and above is done with antennas that don't radiate much into space. HF and longer wavelengths reflect from ionosphere and don't leave Earth. Most unintended transmissions don't have enough power to be detected outside of the Solar system, and they don't employ noise-resistant coding.

However if you take a 60 dBi dish, shove a kilowatt or ten into the feed, and slowly modulate the signal with error correction codes, that transmission might be detectable from a larger distance - depending on how much gain the receiving antenna has.

Suppose the aliens evolved on the dark side of a tidally locked planet and are busy braodcasting light signals at us?

i assume you mean visible light. visible light and all radio frequencies are just certain wavelengths of EM radiation. it's all the same thing. if you are suggesting that SETI won't find ET because they aren't looking in the visible light spectrum, you are incorrect,
http://www.setileague.org/askdr/light.htm

beyond that, SETI listens at what it thinks other technologically advanced civilizations would assume to be a "common" band ... for example, the molecular line frequency of the hydrogen atom. there also some practical limitations that they take into considerations. for example, certain frequencies are not passed through a planet's atmosphere. ET would certainly make the same observations. you can read more here,
http://www.radiosky.com/faq.html#freq

More seriously though it's about timing.

since we don't even know other technologically advanced civilizations exist, we have no idea how long lived they are. a billion years? that stretches our imagination but it's certainly possible. how long did it take humanity to obtain the technology to broadcast and listen for signals from space? 10,000 years?

how long have these possible long-lived civilizations been broadcasting and listening? possibly, a very long, long time. what sort of technology could a million-year civilization apply to the problem? what sort of power could be applied to a broadcast / directed transmission?

For the last couple of decades SETI has been searching the sky methodically looking for any interesting signals around the 1.420 gigahertz range which is the "precession frequency of neutral hydrogen". SETI will now be able to point their radio telescopes at places we already know are interesting and check them on a much wider range of frequencies. I may be hopeful but I can't help feeling it's an exciting time to be alive.

Yeah, any radio astronomer should be able to do this in their sleep.

The classical response is that Arecibo (our biggest telescope, supporting the Earth's most powerful radar) could detect a clone of itself across most of the galaxy. Even this pessimistic (or conservative) estimate is 10,000 light years, a considerable distance.

However, that is detection (with a 1 or more hour integration time). If you want to communicate at a reasonable rate (say, 100 bits per second), you need to be maybe 100 times closer, so the distance you could actually communicate is more like a few hundred light years at best. Optical communications have some advantages, and could certainly match and maybe exceed these distances with existing technology. Note that any probe we are likely to send for a very long time to come will be within these sorts of communication ranges.

http://www.setileague.org/ has loads of info on horns that can be built or bought.

But the SETI League has a use for it.

The SETI league is a good place to find info on doing your own SETI observations.

"They're made out of meat." "Meat?" "Meat. Their houses are made out of meat." "Meat?" http://www.setileague.org/articles/meat.htm

A few hundred years ago it was nearly impossible and highly, highly impractical to load up goods and persons on little wooden ships and sail them across the Atlantic. Yet we did. And yes, we colonized as we went. Did we, though, colonize every single leaf of grass we passed over? Not exactly. There are still wild areas of this Earth, even with humans being able to readily and easily travel to each inch of it.

We haven't colonized the whole planet YET. Ask again after 10,000 years of population pressure and resource depletion. The only factors which prevent this from being inevitable is the need for ecosystem balance (e.g. deforestation v. global warming), lack of suitability or desirability (e.g. Antarctica), or sentimental attachment (e.g. parks and nature preserves).

This doesn't work at the level of planets, and it ignores extra-planetary colonization via orbital structures that exploit the mineral and other resources of an uninhabitable world.

Is it not even remotely possible that another, more attractive system is nearby, and that was the one colonized?

Oh, yes. But how likely is it that no where in the galaxy has been colonized within the span of time that it would take for a radio signal to reach us?

For SETI purposes, we usually only consider stars within 50 light years of us because those are systems that our first radio signals could have reached that could have responded to us in time. Just in that small volume of space, there are 133 stars like our own sun and roughly 1400 total star systems. No one colonized any of these systems?

Okay, so maybe we live in a 50 ly radius "nature park." (Not that I can fathom what one principle would unify all these systems as "protected" instead of treating them individually, but we'll go with that.) What about radio signals from worlds that weren't aware of us at the time they were broadcasting? Why don't we see radar signals within 200 to 600 light-years?

That is a range of less than .1% of the width of the Milky Way (but good enough to cover the thickness), but for us not to have seen someone by now, they would have had to have evolved to space flight sometime in the past few hundred million years -- which is trivial compared to the age of the galaxy. Either we're one of the first (on a galactic time-scale), no one is interested in exploration, or we're alone.

At this point, if there's anyone else out there, they are so far out that we'll have millennia to prepare to meet them. We may as well just operate under the assumption that they aren't there because they'll have no impact on us any time soon.

http://www.setileague.org/articles/meat.htm

http://www.setileague.org/iaaseti/protdet.htm "The discoverer should inform his/her or its relevant national authorities." This is in Step 2 of the protocol. The implication is that Step 3 will not happen, unless Step 2 is allowed.

This practice is not anything new. When Mars meteorite ALH 84001 was suspected to have fossilized life, previous White House administration was notified. Only after getting permission from White House (took about couple of weeks) was that news even published.

These dishes are great for radio astronomy. See http://www.setileague.org/hardware/parabola.htm for details.

http://radio-astronomy.org/

http://www.nitehawk.com/rasmit/ras.html

or even SETI:

http://www.setileague.org/

I have no idea of the actual feasibility of this, but I remember in the early 1980s standing on a rooftop in NYC with a handheld, hand made parabolic antenna, a ham radio, and an Apple ][+ and watching the Apple draw in blocks from a really low-rez 1-bit digital signal from one of the early exploratory probes. For some more recent examples, see here or learn to talk to ham radio satellites here or Google your own!

I nominate planet Earth for a planet-wide Darwin Award:

http://www.setileague.org/editor/metitran.htm

The San Marino Scale is being developed "to quantify the potential impact of transmission from Earth of messages into space".
http://www.setileague.org/iaaseti/smiscale.htm

Aren't they signatories to the SETI Declaration? Oh, maybe not Iran - but the USofA is.

Aren't they signatories to the SETI Declaration? Oh, maybe not Iran - but the USofA is.

> Show me an intermediate result of SETI.

SETI systematically scans the entire sky in every direction, and even in failure to locate signals finds other astronomical events, and provides statistical upper bounds on the possible existence of broadcasting civilizations. An example:

http://seti.harvard.edu/oseti/targeted/results.htm

In addition, SETI is cheap, often piggybacking search onto the back of other funded projects, or using volunteers' time and resources (typically amateur radio and astronomers). It's tens of thousands of private dollars, not hundreds of billions of public dollars that the majority did not want to spend.

http://www.setileague.org/general/compare.htm

Who knows. Maybe SETI will spot an inbound asteroid 30 years in advance of impact and give us time to nudge it. They're the only ones trying to look at the whole sky. Someone should be looking. How embarrassing would it be if the aliens arrive great us, and no one answers?

You can build one from an old C-Band satellite dish. Everything you need to know can be found at the setileague.org website. I would start with the system diagram here.

You can build one from an old C-Band satellite dish. Everything you need to know can be found at the setileague.org website. I would start with the system diagram here.

> I'd find the short story, but there was something a sci-fi writer wrote about aliens being
> offended that meat could be intelligent so the alien scientists decided to cover up what
> they found on earth and took it off the map.

http://www.setileague.org/articles/meat.htm

We're not listening for their 802.11b access points you know. The hydrogen line (http://www.setileague.org/askdr/hydrogen.htm) is considered to be the best place to listen for interstellar communications. The only assumption that is made here is that other civilizations are bothering to try to send communications; if so this is the best place to do it.

While there is still a long ways to go as far as communications are concerned, I'd say we have the basics down pretty well. If you want to transmit a signal to another group of people (whom you don't know) a long distance away (and again, your purpose is for communication) you're going to try the most obvious means possible. This means broadcasting a lot of power in a very narrow frequency with a very high SNR in adjacent frequencies, in a way that would be both meaningful and obseravable to the most simplistic receiver.

Once again, trying to communicate with other (lesser) species using the most complicated system you have available to you would be inherently DUMB. I would hope a hyper-advanced civilization had enough common sense to realize that to maximize your potential targets you must seek the lowest common denominator. This means you don't 1. Use fancy encryption 2. Use patterns that are common in nature 3. Make your signal hard to find by purposefully hiding it in the background noise of the universe, etc.

While your points are valid in that they do affect our chances of finding a signal, you're completely wrong that SETI researches make a bunch of different assumptions that are inherently flawed. The only *real* assumption they make is that another civilization WANTS TO BE HEARD. Everything else follows from that assumption.

Hi, re the bpf, its only a 2 cavity filter made in wg16, cf=8420 with about 50MHz bandwidth, and RF coupled in and out via the standard probed with appropriate matching screws. Using that dish, the signal isnt that strong, its detectable though on an FFT as per the article. There is a nice page on x-band space probe reception with some example audio at http://www.setileague.org/photos/probes.htm
The next plan is to try to hear the orbiters that are currently at Mars, but that will need the 3.7m dish.

It's surprising to see there are still people contributing through dial up modems. I salute your determination, but I think you've got a noisy phone line.

Hi, re the bpf, its only a 2 cavity filter made in wg16, cf=8420 with about 50MHz bandwidth, and RF coupled in and out via the standard probed with appropriate matching screws. Using that dish, the signal isnt that strong, its detectable though on an FFT as per the article. There is a nice page on x-band space probe reception with some example audio at http://www.setileague.org/photos/probes.htm
The next plan is to try to hear the orbiters that are currently at Mars, but that will need the 3.7m dish.
regards,
Paul (uhf-satcom.com contributor)

The byline for the story has me puzzled.

Here's the deal. The SETI project is listening right around the hydrogen line (right around 1420MHz, or 1.420GHz if you like).

Now, let's look at a typical US-based cellphone. They're dual-band capable, operating at approximately 850MHz or 1.9GHz.

The second harmonic of 850MHz is 1.700GHz, nearly 300MHz above where SETI is listening. As for 1.9GHz, its second harmonic is way the heck up at 3.80GHz. When you get up past the third harmonic of any signal, the amplitude is usually so low as to be insignificant.

Now, I don't claim to have all the answers, but it seems to this long-time ham radio op that the possibility of cellphones interfering with SETI hardware is pretty darn slim.

Unless I'm missing something? Perhaps there's an RF engineer, or someone who's seeing something that I'm missing, that would care to comment?

Keep the peace(es).

Both the parent and the grandparent post are using an essentially wrong definition of N in the Drake Equation. N is defined as the number of communicating civilizations, not the number of civilizations that we can communicate with.
To see how this is different, you can use the probability estimate in the Birthday Paradox. Just substitute communicating civilizations for people sharing the same birthday. You will find that the probability of N communicating civilizations will always be higher than the probability of us being able to communicate with them.
I have always wondered why the Drake Equation was not stated as an inequality i.e. the left hand side could always be less than or equal but never greater than the right hand side. Consider for instance the possibility that some civilisation X has heard civilisation Y but simply never bothered to reply...

There are certain parts of the bandwidth which are "off limits" to everyone, public or private.

Take a look here for some of the frequencies.

The idea is that, if we want to take clear radio-frequency "images" of distant images, it makes sense to avoid polluting the sections of the bandwidth where those images are to be found. No, I don't think any of these lower-power trasmitters will be broadcasting directly in these ranges. Unfortunately, most transmitters also transmit harmonics of their main frequency, at lower power. Consequently, everyone gives these frequencies, AND their lower harmonics, a pretty wide berth.

From: Dr. H. Paul Shuch
Date: Fri, 03 Sep 2004 00:41:07 -0400
Subject: SETI public: False SETI@home alarm, courtesy of the press
To: "Dr. H. Paul Shuch"

SETIzens,
Today, I've received nearly a hundred emails about a three-time
SETI@home hit, reported in today's New Scientist. Sorry to throw a wet
blanket on this otherwise exciting announcement, but I have to tell you
the press attaches more significance to this observation than do the
astronomers themselves. Here is the text of an email received today
from SEI@home director Dan Werthimer of U.C. Berkeley (and now in Arecibo):

>it's a zero on the rio scale.

>none of our candidates are very interesting - they are all
consisitent with noise. we will continue to observe many
of the candidates over the next few years, but there's
nothing on the candidate lists we are particularly excited about.

>a reporter from new scientist read the seti@home web pages:
in particular there's a section on "candidate signals" where
we discuss how we score signals and we show the data from
the 220 candidates we re-observed at arecibo 1.5 years ago.
these web pages are old, but the reporter made an exciting
story about them, by exagerating their content and mis-quoting
us and quoting us out of context, and making a press release
about one of the candidates that has a bit higher score than
the others.

>i talked to a couple of reporters today, explaining we've seen
stuff like this for the last 30 years, and it's always turned
out to be rfi or noise, and that there's nothing to get excited
about, and that when you look at 50 trillion bytes of data,
occasionally you'll find patterns that look unusual just from
noise...

>i wish we had something in our data to get excited about.

>tomorrow we'll start using the multibeam receiver you guys made
to map HI in the galaxy. the HI survey will take about five years.
we begin in 12 hours.

>best wishes from arecibo,

>dan

The Rio Scale to which Dan refers is a one-to-ten tool SETI scientists
use for quantifying the importance of a candidate detection. For
details, see http://www.setileague.org/iaaseti/rioscale.htm.

Sorry this one wasn't The Signal, but as you can see from Dan's last
comment, that won't stop us from continuing the search!

Yours for SETI success,
Paul

SETI researchers favor those frequencies because they lie in a metaphorical "water hole" .

I, for one, welcome our No-Definitive-Proof-Of-Existance Overlords... or something.

Oh, and to be on topic, here's some other interesting signals....

Oh, that old chestnut. There's really very little evidence that Bruno's cosmological views had much (if anything) to do with his execution.

We can't currently pick up ET signals equivalent to what Earth is broadcasting to space, even if they were coming from Alpha Centauri; they're just too weak.

This is an analog problem of signal to noise ratio, far more than anything else, so faster processing won't help a bit.

A cryogenic Allen array (to minimize thermal noise), especially in space far from Earth, or on the far side of the moon, would help a tremendous amount.

Usually discussions about SETI itself don't bring that up, because of issues of optimism and such, but it was easy to find web hits on the eseentially identical question: can ETs pick up Earth signals?

"No", says this Seti League guest editorial "ET Detection of Earth TV Unlikely" that goes into a little technical detail.

Similar comments by John Dreher, Staff Astronomer, SETI Institute, although he goes on to assume that ETs would be able to pick up weaker signals than humans are able to -- assuming implicitly that ETs will have better analog technology than we do (maybe they do, but that doesn't help us to do the same).

What about ETs actually beaming a signal at us? Maybe they do so to all nearby stars, one by one. Maybe...would we do that?

"...it has been agreed by all relevant groups that we should not be actively sending out messages to try to reach other civilisations", says another page

Ok, so we would not be so foolish as to attract undue attention from an unknown and possibly hostile galaxy, but maybe ETs will be more naive than that. Or a lot more confident (play ominous music here ;-)

So, bottom line, this is a cool topic, but are we planning to build a cryogenic Allen array in space in the next two decades?

I think we should, but any predictions really should be based largely on that one issue.

P.S. the recent lab verification of photons having orbital angular momentum, able to carry arbitrary amounts of information per photon, implies a new medium we'll need to check for ET signals. Maybe that's what all advanced civilizations use.

See e.g. Photons Spin More Data

We can't currently pick up ET signals equivalent to what Earth is broadcasting to space, even if they were coming from Alpha Centauri; they're just too weak.

This is an analog problem of signal to noise ratio, far more than anything else, so faster processing won't help a bit.

A cryogenic Allen array (to minimize thermal noise), especially in space far from Earth, or on the far side of the moon, would help a tremendous amount.

Usually discussions about SETI itself don't bring that up, because of issues of optimism and such, but it was easy to find web hits on the eseentially identical question: can ETs pick up Earth signals?

"No", says this Seti League guest editorial "ET Detection of Earth TV Unlikely" that goes into a little technical detail.

Similar comments by John Dreher, Staff Astronomer, SETI Institute, although he goes on to assume that ETs would be able to pick up weaker signals than humans are able to -- assuming implicitly that ETs will have better analog technology than we do (maybe they do, but that doesn't help us to do the same).

What about ETs actually beaming a signal at us? Maybe they do so to all nearby stars, one by one. Maybe...would we do that?

"...it has been agreed by all relevant groups that we should not be actively sending out messages to try to reach other civilisations", says another page

Ok, so we would not be so foolish as to attract undue attention from an unknown and possibly hostile galaxy, but maybe ETs will be more naive than that. Or a lot more confident (play ominous music here ;-)

So, bottom line, this is a cool topic, but are we planning to build a cryogenic Allen array in space in the next two decades?

I think we should, but any predictions really should be based largely on that one issue.

P.S. the recent lab verification of photons having orbital angular momentum, able to carry arbitrary amounts of information per photon, implies a new medium we'll need to check for ET signals. Maybe that's what all advanced civilizations use.

See e.g. Photons Spin More Data

In fact, I think that we should seriously question whether the entire premise of SETI@home--that other life forms would transmit data at the radio frequency of water--is still valid

Actually, the searching is done at the frequency of hydrogen, not water. The hydrogen line (1420.40575 MHz) is the precession frequency of neutral hydrogen atoms, the most abundant substance in the universe. From SETI League: "In 1959 two scholars (Philip Morrison at Cornell University and Frank Drake at NRAO) independently recognized that the hydrogen line would be a likely frequency for interstellar beacons. They reasoned that more advanced civilizations would reason that young civilizations (like ours) might already be listening there. Based upon that circular reasoning, Morrison went on to co-author the world's first modern SETI article ("Searching for Interstellar Communications," Nature 184(4690):844-846, September 19, 1959), and Drake conducted a the first modern SETI study, "Project Ozma," a hydrogen line search of two nearby Sun-like stars for possible artificial signals."

But, if you have a better idea of what frequency to look at, I'm sure the SETI project is listening -- no pun intended. ;)

I know i am going to get modded flamebait here, but i dont care.

What a typical fundamentalist christian statement you have there. "The search for extra-terrestrial life is only a substitute for the search for meaning within one's self and with one's God."

Translation: Dont be searching for ET you sinners, cause if you do find proof of intelligent life out there, it shoots giant fucking holes in our dogma. Thats why the catholic church, ever an institution thats quick to condemn anything that crosses their ideology, burnt
Giordano Bruno at the stake for even suggesting the possibility of intelligent life that was not on earth.

As far as your assertions that ET would of already heard us and visited us if they existed, there are MANY possibilities that can include intelligent life not traveling here for any number of reasons. But that goes into the realm of speculation. Seti is about hard science, and the seti project is extremely cautious about making any sort of claim.

That's exactly what Array2k is.

As a ham who works satellites I would not just casually give away the 1.2 Ghz band. Rather, I would like to see WiFi move up to the 5 Ghz band rather than 1.2 Ghz. While I sort of agree that 1.2 Ghz is underutilized, 2.4 Ghz is where the primary downlink for AO-40 is located, and used worldwide. The 2.4 Ghz downlink suffers from interference by microwave ovens, and increasingly WiFi appliances, as well as other services near the band. 1.2 Ghz is a good frequency to uplink to the bird, if you have the equipment, though I agree with you that that 1.2 Ghz stations are hard to find and not easy or cheap to set up properly, due to high feedline losses, and lack of commercial equipment easily modifiable to work in the band.

On the other hand, the technology to clean up signals on microwave ovens could be a bonanza for those hams crazy enough to bounce signals off of the moon in the form of a cheap 500 watt transmitter on 2.4 Ghz. Finally moonbouncers will be able to get armchair copy of EME signals without having to visit Areceibo. I don't want to be in the line of fire of that signal though.

From This place

I would like to see more funding put into projects such as those run by the non-profit organisation Seti League http://www.setileague.org/

Seti League's Project Argus aims to have approximatley 5000 small aperture radio telescopes (generally modified satellite TV antennas) operating in a coordinated effort which allows the entire sky to be continuously monitored. The problem with telescopes such as Arecibo is that because of their large size, they can only see a fraction of the sky. And we don't known when or where we are going to receive 'the call', which is why amateur organisations are important. Just think how many discoveries have been made by amateur (optical) astronomers.

Looniness is quite natural for me, I don't mind at all. But the explanation is entertaining, so I'll share with you. (Hint: negative evidence is still evidence)

Carl Sagan said it better than I ever could. The Drake Equation posits that by now, at least 100 (or anywhere from 5 to 50000, depending on your assumptions) electronics-capable intelligent species have existed in our area of the galaxy so far.

So where are their radio signals? Their space probes? Why does SETI strain fruitless to discover any kind of extraterrestrial signal?

The possible explanations are that there either never was any other intelligent life, or that it lost its ability to send radio signals and space probes shortly after acquiring it. (The Dyson Sphere is another possiblity. So is the Prime Directive, and plain xenophobic paranoia.)

Look at the technology level on earth today. We can already send probes out of the solar system. Given this ability, within 100-300 years at most, we'll be flinging a capsule laden with data storage and solar-powered radio transmitters towards every star we can see.

If we ever manage to colonize other worlds, then over a few millenia there will be an exponential population growth, and nary a corner of the galaxy will be free of us.

But evidently, this hasn't happened yet. Where are all the alien visitors?

Again, using ourselves as an example, the most likely possibility is that whenever technology increases to the point where a species can venture into space, it also allows the species to destroy the viability of it's entire ecosystem. Looking around at the relative popularity of military activities vice space exploration, which one do you think will happen first?

Darwinian evolution dooms us- it creates a locally optimal species, which struggles violently against its peers for resources, always knowing there is a frontier to explore where more open land can be found. But when the frontiers are gone, and the planet is full, it leaves us with a competitive psychology that will be unlikely to abide cooperation long enough for us to "get off the rock".

Look at the science-fiction worlds of something like Clarke's 2001. Flight to Jupiter in 1997? It seemed reasonable then- because it was on the assumption that petty nationalist squabbles wouldn't divert our attention and resources in the meantime. Sadly, that is exactly what's been happening.

I am worried that the seti@home project has lost its focus and gone astray. Seti@home was a romantic notion that captured the hearts and minds^h^h^h^h^h of many of it's users. Mindshare YES, brain power NO.

I think seti@home should transform itself from being a passive project to being an active project. Utilizing the spare CPU cycles of a million idle computers is great but utilizing the millions of idle minds that stare at the screen-saver is revolutionary. Imagine the computing potential. It's incredible.

I know the Seti League's project Argus is a volunteer effort, but unfortunately most of us don't have the space, money, skill, or time required to build a seti microwave station in our own backyard.

My idea is to collect high quality microwave data from antennas such as Arecibo and Parkes and distribute that to users over the internet. Instead of (or in parallel to) a seti@program client, the user would use a signal analysis tool such as baudline to search for drifting signals. Search strategies would need to be conceived and programmed. A collaborative component would need to be built to allow IM like communication, second opinions, and instant peer review. It would be true distributed science that anyone with a creative mind and a computer could participate in.

Since baudline can read and decode the seti@home work_unit.sah files you can perform your own secondary analysis of the seti@home data. Baudline is free but it only runs on x86 linux so give it a try if you can. Most WU data files appear to be pure noise and are boring to look at but occasionally you get an interesting one. Auto-drift rulez.

The ukentucky link below a similar concept that is rough and needs more polish. The potential is there but the implementation is flawed. It also needs more volunteers.

In a word, yes. I have a WinRadio 1550e, which allows monitoring within the waterhole (~1.4GHz) which is where most amateur seti astronomers look.

I have a dish, which had to get signoff from the secretary of state before I could install it :-) The picture shows the width of the house, with the dish being approx 4m across...

Making an interferometer poses major problems with time resolution though - to merge all these amateur radio telescopes together would (a) take a huge chunk of bandwidth for each telescope (ADSL ain't enough...), (b) need excellent synchronisation between the telescopes, which almost all of us don't have, and (c) need the dishes to be steerable, which most of them aren't...

There is however a project argus doing the same thing with lots of individual telescopes. As soon as I'm happy with the s/w running on mine, I'll be a member of the group :-)

And no, no aliens yet :-)

Voltage gain ~= circumference / wavelength.

It's a bleeding edge technology, that you could build at home. Here are some examples and references:
JPL - NASA progress report on a fresnel zone lens.
Zone Plate (reflecting) Fresnel Antennas for Amateur SETI -- Part 1
You'll have to dig, but also use Google to find it.

You should be able to design a flat antenna from solid foam insulation with foil on both sides by removing the foil at the right places. There are design programs to do the math. Aiming is going to be tricky, but should be no more difficult than any other installation.

Good luck.

--Mike--

The dish (3m diameter minimum) will set you back ~150 quid, the radio receiver (1.4GHz typically) is ~300 quid for the WinRadio 1550e (PC-attachable high-frequency radio receiver), and the LNA (low-noise amplifier), feed-horn, cable and fittings came to another 300 quid. So a total of ~750 quid.

All of this is in the UK, and apart from the dish, I bought new kit. I'm sure that (a) outside the UK it's easier to get large dishes, and (b) if you bought 2nd hand, you'd be able to get the price of the hardware down. You can even make your own components if you have the knowledge.

A good source of info is the setileague website for the mini-manual or the UK site run by Jenny Bailey, although it was a bit out of date last time I looked.

Anyway, this time next week, I should be searching for aliens from my back-yard too :-)

Simon.

Doesn't that assume that the life forms will be something like us? Terry Bisson has a great perspective on this from his short story/play "They're Made Out of Meat":

"They use the radio waves to talk, but the signals don't come from them. The signals come from machines."
"So who made the machines? That's who we want to contact."
"They made the machines. That's what I'm trying to tell you. Meat made the machines."
"That's ridiculous. How can meat make a machine? You're asking me to believe in sentient meat."
"I'm not asking you, I'm telling you. These creatures are the only sentient race in the sector and they're made out of meat."
"Maybe they're like the Orfolei. You know, a carbon-based intelligence that goes through a meat stage."
"Nope. They're born meat and they die meat. We studied them for several of their life spans, which didn't take too long. Do you have any idea the life span of meat?"
"Spare me. Okay, maybe they're only part meat. You know, like the Weddilei. A meat head with an electron plasma brain inside."
"Nope. We thought of that, since they do have meat heads like the Weddilei. But I told you, we probed them. They're meat all the way through."
"No brain?"
"Oh, there is a brain all right. It's just that the brain is made out of meat!"
"So... what does the thinking?"
"You're not understanding, are you? The brain does the thinking. The meat."
"Thinking meat! You're asking me to believe in thinking meat!"
"Yes, thinking meat! Conscious meat! Loving meat. Dreaming meat. The meat is the whole deal! Are you getting the picture?"
"Omigod. You're serious then. They're made out of meat."
"Finally, Yes. They are indeed made out meat. And they've been trying to get in touch with us for almost a hundred of their years."

Read the rest here (it's very short).

wouldn't be much harder to do "Set Time on VCR".

Yeah if it's connected via the computer... All it would need is the key sequence for your vcr along with the correct ir codes... It could pull the time from a "Totally Accurate Clock".

He didn't, as you state "come up with the Drake equation during the Green Bank conference"--he was one of the organizers of the conference, and used the equation to structure the agenda.

I stand by my interpretation (which seems to be reasonably common).

-- MarkusQ

"So... what does the thinking?"

"You're not understanding, are you? The brain does the thinking. The meat."

"Thinking meat! You're asking me to believe in thinking meat!"

"Yes, thinking meat! Conscious meat! Loving meat. Dreaming meat. The meat is the whole deal! Are you getting the picture?"

"Omigod. You're serious then. They're made out of meat."