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SETI League FAQ Sheet
(Frequently Asked Questions)

Q: What, exactly, does The SETI League, Inc. hope to accomplish?
A: We hope to help answer the fundamental question which has haunted humankind since first we learned that the points of light in the night sky are other suns: are we alone, the sole sentient species in the vast cosmos? What we seek is existence proof, rather than dialog with alien civilizations.

Q: How do you expect to accomplish this goal?
A: Radiotelescopes will allow us to detect microwave radiation, either incidental or deliberate, from other technologically capable civilizations. The coordinated use of thousands of small radiotelescopes will maximize our chances of success.

Q: What frequencies should those radiotelescopes scan?
A: Initially, we are concentrating our efforts on developing techniques to scan the so-called Water-Hole, extending from 1420 to 1660 MHz. Of course, there are many other interesting frequencies worthy of study, including the optical spectrum, and individual SETI League members are free to pursue whatever strategy they find most appealing.

Q: What equipment is required?
A: The typical amateur SETI station consists of a 3- to 5-meter diameter satellite TV dish, a suitable feedhorn, low-noise preamplifier, microwave receiver, personal computer with sound card for analog-to-digital conversion, and appropriate digital signal processing software. For more details, see The SETI League Technical Manual.

Q: I already have access to a larger dish. Can I use it?
A: Of course! Here's a case where, if a little is good, a lot is better. Larger antennas have higher gain, hence greater sensitivity. However, as antenna size increases, sky coverage decreases correspondingly, so we still have need of several thousand smaller dishes to scan the entire sky.

Q: A large dish is out of the question for me. Are other antennas feasible?
A: Absolutely! Yagis, quads, helices and loop yagis have all been used successfully for EME, radioastronomy, and satellite communications, so why not SETI? The only penalty will be in bandwidth.

Q: What will The SETI League, Inc. provide?
A: Kits, plans, software, and coordination. Having built a demonstration station, we have documented it fully in our Technical Manual, as well as through articles in various amateur radio periodicals. We have arranged to provide hardware kits for those who wish to assemble parts of their own systems, and can recommend several commercial manufacturers for those who prefer to purchase it. Based upon the geographical and terrestrial interference constraints of our various participants, we will recommend specific antenna-aiming coordinates, so as to maximize sky coverage. And we encourage our members to use our World Wide Web site and other Internet resources to coordinate their activities and share results.

Q: What will all this cost me?
A: Initially, just your membership dues. The cost after that depends on what you already possess. Several SETI enthusiasts with an existing satellite TV dish and suitable computer have gotten up and running by investing about five hundred dollars. Others, starting from scratch, have spent several thousand dollars on their systems. Experience building electronics equipment (from scratch or in kit form) will certainly lower the cost. And like most hobby efforts, it is expected that you can start off simple and cheap, and get more elaborate and expensive as your time and resources dictate.

Q: Where can I get the required equipment?
A: There are numerous sources. We have already designed our own suitable preamplifiers, antenna feeds and receive converters, which many of our members have built. In addition, we can recommend a wealth of existing commercial equipment which will work quite well for SETI. See The SETI League Technical Manual for details.

Q: What can I expect to hear?
A: Probably nothing at all, for a very long time. When you do hear a coherent signal, most likely it will be caused by terrestrial or satellite interference. Thousands of us may have to work for years to hear The Signal, if we ever do. SETI is definitely a gamble, with long odds but high stakes.

Q: Won't I become discouraged?
A: That's a legitimate concern, since SETI offers little in the way of instant gratification. To hold your interest, The SETI League is planning a number of "on the air activities" of the type you would expect from ham organizations. We plan to bounce some interesting signals off the moon for your receiving pleasure (and to help you test your receivers). We anticipate generating strange modulation modes as a challenge to your digital signal processing skills, along with some competitions (with, of course, prizes!)

Q: How can I get further details?
A: First, if you haven't already done so, we urge you to become a member of The SETI League, Inc. Only be establishing a sizable membership base can we have the resources (fiscal, technical and operational) necessary for success. Members will receive our quarterly newsletter, SearchLites, as well as mailings whenever new hardware or software becomes available. You are also invited to browse our World Wide Web site frequently; that's where we archive all technical materials. The URL (Web address) is

Q: How do I join?
A: From our website, you may download any or all back issues of SearchLites our quarterly newsletter. You will find a membership application on the back page of every issue. Or, you may download a SETI League leaflet (which includes an application form) from our website, at If you reside in the US or Canada, you may call our free Membership Hotline at 1 (800) TAU-SETI, and leave relevant information (including your name, address, membership category, Visa or MasterCard number, and expiration date) on our answering machine.

Q: Why should I join?
A: The "Top Fifteen Reasons" are listed at But I'm sure you can think of more.

Q: How can I get personal technical assistance with my system?
A: The SETI League field service organization consists of a cadre of volunteer Committee Chairs and Regional Coordinators all over the world, who provide limited technical consulting to the extent that their day jobs and personal commitments permit. Their email addresses are linked from our website, at may also email to headquarters at info_at_setileague_dot_org with their technical questions. When possible, you will be referred to a specific publication which answers your question. Because of extensive travel schedules, reaching us by telephone is sometimes difficult; it is best to stick to email or the postal service.

Q: What is The SETI League's position on UFO's?
A: In recent years a number of phenomena (reported sightings, abductions, the Roswell incident, crop circles, Area 51, etc.) have defied explanation. These matters are certainly interesting, and may be worthy of further study by qualified experts. We at The SETI League are primarily radioastronomers, arguably qualified to recover and analyze microwave signals. Beyond that we claim no particular expertise. We will continue to concentrate on what we know best, and encourage others to do the same.

Q: What if I don't want to build a SETI station?
A: "They also serve who merely pay their dues." Your tax-deductable contributions to The SETI League, Inc. will help to support this important research, and will enable you to experience vicariously the thrill of discovery. Please join us! There are also many projects, both technical and non-technical, in which non-observers are encouraged to participate. These are announced from time to time in SearchLites, our quarterly newsletter, and on The SETI League's website.

Q: How much of my contribution is spent on salaries?
A: None of it! At one time, The SETI League enjoyed the luxury of having as many as two (!) paid employees. Since 2004, however, we have been an all-volunteer organization. Except for some necessary hired professional services (legal, secretarial, accounting, etc.) everything is done by members like you. So please be patient if it takes us a while to respond to your inquiries and requests.

See also: Ask Dr. SETI ®

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