Subjects to Explore with the Data

Joachim Köppen DF3GJ Kiel/Strasbourg/Illkirch Summer 2004

• search for possible solar radio bursts. The NOAA solar activity archive for 2004 gives the information of all identified solar bursts, and the Radio Jove Data Archive at GSFC are also very helpful.
• some type of solar radio bursts have a characteristic shape: they look like shark fins, rising quickly but going down more slowly. Maybe you find some candidate bursts that are not listed in the NOAA data!
  Recently while listening, I happend to hear an increase of the noise, fast rising - slowly falling. It was nice clean rushing noise, unlike any interference or communication. Later, the NOAA list showed that it had indeed been solar event No. 3200 of 15 June 2004, a type III/1 radio burst!
• the twilight and night-time data should be hunted for Jupiter bursts - check whether at the times suggested by the Jove prediction software there are bunches of impulses. {However, during this summer, Jupiter will be above the horizon only during the day. Solar noise and noise from the ionosphere as well all radio emissions reflected by the ionosphere will be too strong to hear much of Jupiter!) But who knows? Maybe you catch Jupiter just after sunset! Anyway, we must have a very low background, such as seen in this recent observation. John has an enviously low noise site; the background of about 35 kK would come mostly from the Milky Way:
  

• How does the background noise level and the amount of daytime impulse noise vary with time of the day and time of the week? What is natural, what is man-made?
• Watch out for changes in the background: it could be that some man-made interferences starts or stops, that the ionospheric conditions change the reflection of short wave signals, or even we might experience that the ionosphere becomes opaque as a consequence of a strong influx of solar particles (Mögel-Dellinger effect) which cause short wave communication to break down... Here are two examples during the huge solar storms in October 2003:
  

• Some of the impulse-type noise comes from lightning discharges in thunderstorms. On the Web, one may obtain real-time maps of the lightning activity in any area of the Earth. How does the occurrence of crashing-type pulses relate to the presence of thunderstorms in your area? Can one say at which distances the interference becomes noticeable?
• Do you notice anything in the level of the noise around sunrise or sunset? Can we pick up the emission of the quiet sun? Are we sensitive enough?
• Is the rise of noise in the morning the mirror image of the decrease of noise in the evening?
• Can we pickup signals from the centre of the Milky Way? During July and August, Sagittarius is culminating in the night, so we might see any significant increase of noise about the time when it's in the peak of the antenna pattern? Jason Shinn from Canal Fulton, Ohio captured this extraordinary beautiful plot in August 2004:
  

  One sees very nicely the strong daytime noise stopping at about 03 UT - which is local evening. Nonetheless, the emission from the Milky Way was already present, it peaks when the Galactic Centre culminates over Ohio ("Local Transit"). During the following night the signal becomes weaker, and vanishes, as the Galactic Centre sets at about 07 UT. Later, the daytime noise appears again!

• How stable is the calibration of the receiver? Do the calibrations taken at the beginning and the end of your observation run (with the same receiver and the same volume setting) give the same readings?
• the most pertinent problem in Strasbourg in winter has been the mystery of the origin of the periodic night-time interference. Since the exchange of the flickering street lamp in front of the ISU building has not prevented the interference to come back at times, we still are faced with the problem: What can we do to find and prove its origin? What in the characteristics of the signal (repetition period, on-off ratio, start/stop times) could give us a hint? For example: the period seems to be quite constant: 47 sec. How constant is it? How does the amplitude (high value/low value of noise level) vary? Variations from day-to-day? Difference between week and weekend?
• If it continues to be present and if we cannot do anything about it, e.g. by fixing a faulty equipment, could we do some clever processing of the data to help us pick real signals? For instance, during the 10 sec interval of low noise, the level seems to be just below 100000 K, only twice of the galactic background: so it might still be possible to pick up bursts from Jupiter.

• Wherever you run the RadioJove receiver, you might be faced with similar or different problems ... No need to dispair! A careful study of any problem or interference might turn out to be as challenging and exciting as detecting signals from Little Green Men ... Only with meticulous studies and clever approaches you have a chance to identify the source, uncover perhaps some weird physical effect causing it to behave like that, and then fix it!

• There are many events of short impulses during the day. Is there a possibility to identify these impulses and build a software filter to remove them? Any clever ideas?
• I've written a Java program SkyPipePlotter which can read the data files. It permits to calibrate the data (with the signals done by the calibration sequence) and to display the data in proper units (dB over room temperature, or noise temperature). This could be used to make some data processing ... You might devise some signal processing techniques which we can add to the program. The source code would be at your disposition.