Monday, January 5, 2009

Here is a picture of our 5 meter diameter SETI dish.

Thursday, January 1, 2009


At the Teaneck NJ campus of Fairleigh Dickinson University, School of Computer Sciences and Engineering, we have a project where students design, build, and test equipment that is searching for microwave signals coming from outside the solar system.

SETI (Search for Extra Terrestrial Intelligence), and in particular FDU-SETI, is aimed at detecting radio wave signal patterns which could not have been produced by any natural mechanism which we know and understand. We hypothesize that some of the countless beings living in the light of distant suns may also radiate signals into the radio environment and we, on earth, stand a reasonable chance of detecting them.

Many amateur and professional SETI stations (including FDU) are listening at 1420 MHz (resonant frequency of hydrogen atoms), because it is reserved for listening only and because the attenuation of inter-stellar space is very low at that frequency. At FDU, a five-meter diameter parabolic dish is setup for the SETI project. This project allows the students to design and build purposeful hardware while learning how to work with others on a team (graduate and undergraduate). The signal collected by the dish is immediately amplified by a solar powered low noise preamplifier and sent to the equipment in the laboratory for processing and analysis.
This project is not solely about hearing signals from outside the solar system, it is also about designing and building something and getting it to work. FDU-SETI has at its center, a five meter diameter parabolic dish, with the students designing, building and testing nearly everything else needed.

For Seniors, the graded project is, in effect, a practical application of four years of theory and labs in the student's field of study. For graduate students it is fertile ground for design simulation and research. FDU-SETI has been an excellent environment for learning about teamwork and advance planning, technical writing and product testing -- all to complement the student's design / parts procurement / fabrication and technical presentation skills.
Progress of project to date - Numerous students have brought the program to the point where a SETI station is up and running (part-time) in one of the labs at FDU/Teaneck NJ, with a variety of commercial and student-designed/made circuits. Some of these circuits are slowly being replaced with more sophisticated student developed designs.

Here is a list of completed tasks and tasks being worked on or not yet started.
All described tasks are to be done by the students, over a period of several semesters, with the assistance of faculty advisors. Some tasks will take multiple semesters, with another student taking over where a graduating student leaves off. For each task below, the student will formally document the problem or question, the alternatives, the tradeoffs, and the reason for the decision or design approach. The task also includes the actual design or development effort, as applicable. The student must submit an acceptable proposal and complete a substantial amount of work, properly documented, in order to receive a good grade. Typically, two or more tasks in the list would have to be combined to make up enough of an assignment for the student in order for it to be acceptable for EE Senior Project (for 3 credits). For one credit (technology), one task is usually sufficient. You don't have to be working on SETI for credit, volunteers welcome.
Each student will prepare his/her report for his/her portion of the overall project, as a term paper and possibly for presentation at a local or regional contest or conference. As appropriate, design details must be included in the report / paper. At a minimum, unless the student graduated in the Fall, the student is expected to present a talk on his/her project in the Spring at FDU Research Day.

As indicated by the word DONE, some of the tasks are completed already. They may be revisited at another time, but probably not.
1. Write an objectives statement, with a section on Technical Specification. DONE
2. Investigate RF wavelength windows for inter-stellar propagation. DONE, we're listeningat 1420 MHz.
3. Investigate distances to nearest stars (and other stars with known planets) and their directions (optional)
4. Calculate signal levels at earth due to a representative source. DONE, -140 to -200 dBm
5. Determine minimum antenna area, sensitivity, side and backlobes required to receive a typical signal and to reject earth based interference. DONE *
6. Select antenna type based on required effective area, sensitivity, and other considerations. DONE, parabolic dish
7. Analyze and decide whether the antenna must be steerable (or point straight up or stare at Polaris, the north star that is always above the horizon) DONE, it's not steerable.
8. Do a make / buy decision on the antenna. DONE, donated **
9. Arrange to have the antenna mounted somewhere on campus DONE, next to Muscarelle Hall
10. Design temporary mounting pedestal (must survive 50 year windstorm) DONE, uses 2X12 planks.
11. Design steel (permanent) pedestal that can point the antenna in a desired direction (defer) 12. Fabricate steel pedestal (donated professional labor?) and concrete piers in grassyarea adjacent to Muscarelle building. Install pedestal on piers. (defer)
13. Design and make feed "horn" for collecting signals that have been intercepted by the parabolic reflector DONE (cylindrical type)
14. Perform preliminary tests and calibrations on antenna (horn + dish) using a laboratory source and known long range (satellite) signals DONE, data available.
15. Calculate transmission line losses if preamplifier is not antenna mounted, analyze if this approach is feasible. Repeat for other types of transmission lines. Calculate line losses from preamplifier to next stage, etc. DONE, data available
16. Calculate detailed performance requirements for preamplifier (noise figure, gain, etc.) and write procurement / design specification DONE
17. Buy (preferably surplus military) or design/build/test preamplifier that satisfies the requirements DONE, purchased
18. Test antenna and preamplifier combination (needs redoing)
19. Obtain surplus or loaner microwave receiver to allow signal reception temporarily until student-built equipment is ready DONE, have loaner spectrum analyzer from BAE Systems
20. Determine requirements for signal filtering (RF / IF) and write procurement / design specification
21. Buy or design / build / test RF and IF stages (using inexpensive, commercially available electronics if possible) DONE (built from kit)
22. Test antenna, preamplifier, RF and IF stages together (preliminary tests done, need redoing)23. Design and make ET signal modulation source (to provide "realistic" test signal, use with portable signal source)
24. Determine approach for detection (extraction of information from signal) and digitizing of signal STARTED
25. Write design specification for detection and digitizing of signal
26. Design or buy hardware and write software for detection and digitization STARTED
27. Build and test detection and digitization hardware
28. Code detection and digitization software STARTED
29. Test hardware and software together with antenna
30. Determine the nature of the interfering signals to be expected (such as WFDU?) DONE
31. Setup audio amplifier and speakers / headphone (DONE, revising setup)
32. Understand, use SETI-FOX software where practical
33. Run new coax cable to lab from antenna (DONE)
34. Determine requirements for signal analysis (including false alarm reduction, signal enhancements, etc.) and write design specification
35. Design signal analysis hardware and software and write hardware design and soft requirements specs
36. Code software for false alarm reduction, signal (structure) recognition, etc.
37. Test false alarm reduction and signal recognition software with the rest of the setup 38. Determine requirements for signal collection and archiving DONE
39. Select and buy computer for signal archiving DONE
40. Design, build auto-dialer (call cell phone if interesting signal detected) (Haveintrusion detector type autodialer, needs modification to respond to signal detection)
41. Test computer standalone
42. Test and calibrate entire setup
43. Collect signals, if any
44. Calculate limit of detectability for this station, and/or limit of source signal power for non-detection (if that is the case)

* the backlobe and interference calculations have not been done** we have an antenna, a 16 foot diameter parabolic dish