SETI League Technical Manual -- Systems
The SETI League has entered into an agreement with noted component supplier Down East Microwave Inc., whereby DEM will supply microwave radioastronomy and SETI hardware designed by The SETI League, in both kit and assembled form. The agreement provides for substantial price discounts to SETI League members. A SETI League-designed preamp module (DEM model SETI-LNA) has been available since late 1995, and is in use by numerous SETI League members worldwide.
As our gift to you, all SETI League members in good standing will receive from Headquarters upon request a $10 cash discount coupon for this preamp. You can also purchase just the printed circuit board and documentation package, although our members' discount coupons are not applicable to such purchases.
Please Note: Successful completion of the above preamplifier kit demands precision microwave assembly technique and, in some cases, the use of complex electronic test equipment. This kit is considered appropriate to advanced microwave experimenters. SETI League members lacking extensive experience building and troubleshooting microstrip assemblies should purchase an assembled and tested unit, since a nonfunctional or improperly assembled kit probably can't be economically repaired, even if the vendor is willing to try.
For those preferring an assembled and tested preamplifier, Radio Astronomy Supplies of FL, which is run by SETI League member Jeffrey Lichtman, offers SETI League members its quality LNAs for $155.00 US plus shipping (US 5.00, Europe 15.00, Pacific and Other 20.00).
Phase II Progress to Date:
First out of the starting gate with a stable, low-noise down-converter for the 21 cm band was SSB Electronic GmbH of Germany. Their Model UEK-21 Down-Converter was developed in cooperation with Peter Wright, our own volunteer coordinator for Germany. The unit converts two MHz of spectrum centered on the 1420 MHz hydrogen line, down to a 28 - 30 MHz Intermediate Frequency. The 10 meter IF is compatible with most members' existing SSB communications receivers. The UEK-21 is priced at around 250 Euros.
Radio Astronomy Supplies has for some time offered our members its UltraCyber and SpectraCyber series of radio telescope receivers. They incorporate a downconverter to shift the hydrogen line to a 70 MHz IF. Jeffrey has recently added a 70-to-28 MHz "SETI Ready" converter box to his product lineup, which, along with a suitable HF receiver, will allow the UltraCyber or SpectraCyber to do double duty as a SETI receiver. A SETI-optimized version of the Cybers was introduced in 1999, bundled with an LNA and feedhorn, and sold as the Seeker 2000 system. Though now discontinued, its data sheet is still shown here for historical reasons.
And finally, the SETI League downconverter demonstrated at our 1997 Annual Meeting shifted a 4 MHz segment near the hydrogen line down to the 2 meter (144 MHz) ham band. At the 1999 Southeastern VHF Conference, the prototype measured 49 dB of conversion gain at 1.85 dB noise figure. It shows 50 dB image rejection and better than 30 dB spurious rejection. Photos of the prototype appear here. The unit was offered commercially by Down East Microwave Inc., in both kit and assembled form. That company has subsequently withdrawn this product from the market, as market volume proved insufficient to justify its continuation. Pricing (listed here for the historical record) was as follows:
| Model | Description | List Price (US Dollars) |
|---|---|---|
| 1420-144PCB | Printed Circuit Boards and documentation only | $30 |
| 1420-144K | Mini-kit: Printed Circuit Boards and components | $135 |
| 1420-144CK | Full kit, including hardware and enclosure | $165 |
| 1420-144 | Fully assembled and tested converter | $195 |
When the downconverter was introduced, SETI League members in good standing received a coupon good for a $10 discount off the purchase price of the converter or kit (discount did not apply to the purchase of printed circuit boards).
Please Note: Successful completion of the above downconverter kit demanded precision microwave assembly technique and, in some cases, the use of complex electronic test equipment. This kit was considered appropriate to advanced microwave experimenters. SETI League members lacking extensive experience building and troubleshooting microstrip assemblies were encouraged to purchase an assembled and tested unit, since a nonfunctional or improperly assembled kit probably could not be economically repaired, even if the vendor were willing to try.
The Down East Microwave downconverter was used in an all-new SETI League receiver, which was first demonstrated at the SETI in the 21st Century Conference in Australia in January, 1998. The receiver, which added a direct-conversion phasing type 2-meter ham receiver (The popular Rick Campbell "R2" design) after the downconverter, provided Project Argus participants with everything needed between the LNA and their computer. Driving the appropriate computer and software, it was capable of analyzing 22 kHz (or optionally, 44 kHz) of spectrum centered on the 1420 MHz hydrogen line, to 10 Hz resolution, in real time. We sought commercial vendors interested in producing and marketing this complete receiver package under license from The SETI League, Inc. Unfortunately, in the nine years since the prototype was demonstrated, no manufacturer has materialized.
Phase III Progress to Date:
SETI League engineers have recently completed an improved feedhorn design, which is being offered commercially by Radio Astronomy Supplies of FL. List price is $140 US. Jeffrey Lichtman, owner of Radio Astronomy Supplies, will be extending discounts to his fellow SETI League members. A $10 discount coupon may be requested from Headquarters by any SETI League member in good standing.
Pulling All Three Phases Together:
Olde Antenna Labs of Denver has introduced their Complete SETI LNBF, combining a helical antenna feed, low noise preamplifer, and hydrogen line downconverter, all in a weatherproof radome ready for mounting at the focal point of your TVRO dish, and all for under $400 US. Just add your own dish, computer, and a 2-meter SSB ham receiver, and you're on the air!
Summary:
You still can't walk into your local Radio Shack ® store and purchase a complete SETI station. But all the necessary pieces are now available commercially. In most cases, more than one option exists. For well under $2000 US, a dedicated amateur radio astronomer can now piece together a system which will exhibit performance adequate to detect Earth-type electromagnetic emissions from the nearest stars. For details on how to string the pieces together into a credible SETI station, see The SETI League Mini-Manual.
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