SETIEasy was written to reduce the need for students in routine screening of data files. The program supports "signal de-chirping" and long signal integration times. SETIEasy was designed to seek signals from 4 seconds to up to several minutes in time, using a series of shorter signal integrations. Given the relatively small size of the typical Project Argus radiotelescope, weak signals "buried" in the noise can reasonably be expected. CoolEdit and SETIEasy now analyze our data in real time, so the program is a success. Students now only check selected files (such as those collected in the direction of a new supernova) for complex signal patterns that would not integrate over time into a stronger signal.
The ASRG uses computer algorithms to scan all of the data collected from the radiotelescope. ASRG members record signals from the remote radiotelescope and transport the data to the lab. The data are then placed on servers as described on Performing SETI Data Analysis. The screening by students for signals involves calculating the FFT (fast Fourier transform) of the data repeatedly over time. Using such programs, a file is played and displayed as a spectrogram. It is the task of the students to watch the spectrogram for possible "hits." It might well be easier for students than for a program to detect the totally unexpected. Using the Analysis views in CoolEdit gives exceptional sensitivity to signals that do not shift greatly in frequency with time (even better in most cases than SETIEasy). However, students fatigue over time, but SETIEasy on a computer does not. In addition, most signals from space can be expected to show a frequency shift with time that limits the duration of any signal integration. (The rotation of the earth produces enough frequency shift through the Doppler effect to obscure signals in this fashion.)
After scanning a file, update the news post as described on Performing SETI Data Analysis (N.B. SETI League protocol does not permit anyone to share any information about suspicious signals with anyone outside the established League channels, in order to prevent hoaxes and false alarms.)
So, these are the basic steps:
Read this page thoroughly, download SETIEasy and an audio conversion program like CoolEdit or GoldWave if you do not already have one, download a file from the server, post an In Progress (Downloaded) message, screen the file, and post a Completed message. NOTE: SETIEasy will flag interference signals and "birdies" as Unusual Signals even though those signals are in our Known Interferences Log. At our observatory, these flags are used to trigger a check of the log. If the signal is in the log, the file is posted on the public data server where it is accessible. Otherwise, the file is held for confirmation of the signal by other Project Argus stations.
Download a file from a server. Use the Preferences selection in your web browser to instruct the program to Save To Disk any sound files you will screen, or right-click on the file(s) and select "Save As" from the pop-up menu. Please check the discussion groups for follow-up posts about the files to make sure that no one else has already screened the file you choose. (This is usually not a big problem, however, as files are removed from the server once a report is received on them to make room for additional files.) Try to analyze the most recent files first, as these have the best chance of being confirmed by another station if a signal is detected. Do not bother to run files that have a follow-up post that indicates CoolEdit FFT over time, MathCAD, or "SETI-EZ" is Completed, as they have already been screened by a student. You can also skip files labeled "in progress", as they are being analyzed at that moment by someone else.
Download SETIEasy as a .zip file (includes the readme), or a .wav and rename it to SETIEasy.exe before running it (naming the program as a .wav file lets students download it in binary with a web browser by right-clicking on the file name without having to have an unzip utility). Double-clicking on the program icon should bring up a screen that looks like:
Type the name (and path if necessary) of the data file and hit the Enter key. The screen should then look similar to this one:
You may have to wait a number of minutes before the first output appears. SETIEasy calculates FFTs over a range of signal durations in an effort to find a duration with a good signal-to-noise ratio. The best S/N is achieved when the FFT data duration is the same as the actual signal duration. The pieces of data taken for FFT start small, and become progressively larger.
For most data from the radiotelescope, the screen should look something like this:
Occasionally, an unusual noise is detected. When this occurs, post a report on the appropriate discussion group after going as far as you can through the checklist at Detecting Terrestrial Interference and Spectral Artifacts with other software like CoolEdit or Baudline. These noises are almost certainly some form of interference. Examining outData.txt for the time the unusual signal occurred enables you and others to go directly to the right spot in the right file to begin additional testing.
The Unusual Signal flagging does not have to be continuous because there may be a repeating noise or signal. The ASRG has tools to examine the data more closely, and can move the radiotelescope to track the signal or establish its terrestrial location if it is an interference. To prevent hoaxes and/or undesirable publicity about what is probably nothing, do not share information on data files you examine with anyone else. Remember, any signal most likely arises from interference. An authentic extraterrestrial signal would exhibit a number of measurable signal characteristics, such as a Doppler shift as the signal source moved toward and away from Earth as the planet rotates and translates relative to the deep-space source. (Click here for an Excel spreadsheet to calculate the expected Doppler shift from rotation for any location on earth.) For our telescope in its typical orientation, the expected Doppler shift is +/-6.07 Hz/min. This means that any real "signal" would be shifted by the rotation of the earth by 6.07 Hz per minute of recording. If the signal passes all of the local tests for interference, other Project Argus radiotelescopes will be given the coordinates to try to confirm the signal.
Click here to see examples of interference signals.
The reporting methods are described in Where We Have Been Looking Lately.
Every time you download a file or complete analysis of a data file, please report your work by updating the post with a follow-up post. When you download a file, follow up with the file name and "In Progress". This helps to reduce unnecessary duplication of effort by others who may download the same file. However, please do not download a large number of files at one time unless you can analyze them in fairly short order. Our goal is to keep the time a file waits for analysis to a minimum to increase the chance of another station confirming any signal that might be detected.
If you find any unusual signals, post it in a report of file completion. Report the time the signal occurred in the file and include a screen capture image of the signal as a GIF or JPEG if possible. Remember, in nearly 40 years of SETI, no signals from intelligent extra-terrestrial civilizations have been confirmed, so most suspicious signals turn out to be interference. We will share the results of our signal tests with you, and any credit that may be due based on the results of signal analyses and confirmatory testing by other Project Argus stations.
If you have any problems doing the data screening, please let us know and we can help. We appreciate your interest and time. Thank you, and good luck!