Jupiter is a wonderful object for radio study. It is somewhat predictable and yet often surprising in its violent outbursts below 40 MHz. You can receive Jupiter using relatively simple equipment or you can construct complex spectrograph receivers and build monstrous antenna arrays to capture its more subtle messages. The complex relationship between the gas giant planet and its volcanic moon Io is not completely understood, but we do know these bodies work together to produce "radio noise storms" as they pirouette through space. Many factors come into play for the amateur radio astronomer who tries to capture a noise storm. In order maximize your chances of success, you should take time to understand the potential hurdles and optimize your equipment for this task.
The emissions we can hear are often referred to as decametric noise storms, because the waves are tens of meters long. Okay, it is possible to hear Jupiter from 15 to 38 MHz, but what are the optimal frequencies? The consensus seems to be that 18 MHz up to about 28 MHz is a good place to listen. A good rule would be to pick the lowest frequency in this range which was not being hindered by ionospheric refraction.
Unfortunately, during times of high sunspot activity, (the last peak was in 2000), the ionosphere can remain excited all night long. One way to judge if the ionosphere will get in your way is to check a ham band just below where you intend to listen. If you hear amateur radio signals coming in from distant places on the ham band, then you know that the ionosphere is reflective enough that it is bouncing those signals. If the ionosphere can keep the amateur radio signal under its blanket in this way, then it will likely be bouncing away the signals from Jupiter, and you will not hear them. The amount of bending that the ionosphere imparts to a radio wave is inversely proportional to the frequency of the signal. Thus, you can often escape the ionospheric effect by going higher in frequency. Understanding the behavior of the ionosphere is then crucial to your success. You should understand that the ionosphere changes in behavior throughout the day, and is usually much more active while the Sun is above the horizon.
As a practical matter, you will have to pick only as many frequencies to monitor as your equipment will allow. The real limitation is the range of frequencies over which most antennas will operate effectively. A good directive antenna is usually only good for a range of about 500 kHz or so. There are some exceptions, log periodic yagi arrays, and arrays of conical helices are quite broad banded but are not commonly owned by amateurs because of their size. You will probably settle on one or two frequencies and build the best antenna you can for those. 18 MHz and 24 MHz might be good choices.
There is one more long term factor you should know about, the Jovicentric declination of the Earth.
You may want to use a convenient program that produces customized predictions for your location. Radio-Jupiter Pro 3 provides a wealth of information for the Jupiter radio observer. It is also useful for tracking the Sun.
Click here for the Jupiter antennas page.
Click here for the Jupiter receivers page.
Click here for a description of my Log Periodic Dipole Array.
You can record the envelope of the audio signal on a strip chart recorder or on your computer using a sound card and the appropriate software. Radio-SkyPipe software fills this role beautifully. With the Pro version of Radio-SkyPipe you can record wav files on your computer in addition to the charts of the sounds. From such charts the pattern of the storm as a whole can be discerned.
S Bursts (slowed down 128 times)
Bursts from the 1999 SARA conference
Io B Storm of 09/23/2000
Io B Storm of 11/27/2001 Several charts and sound files. An exciting storm.
Io B Storm of 01/05/2002 chart and sound files of S bursts.
Io B Storm of 03/10/2002 L burst example sound file.
Io B Storm of 03/10/2002 S burst example sound file.
Io-C Storm of 04/28/2008 Spectra from SDR-14
Io-B Storm of 04/29/2008 Spectra from SDR-14
Io-A Storm of 05/12/2008 Spectra from SDR-14 (very weak).
Io-A Storm of 06/22/2008 Spectra from SDR-14
Ruggero Ulivastro has a great page of guidelines for making good Jupiter observations. Be sure to check out Ruggero's free software that calculates the power of Jupiter bursts.Free Spectrograph Software allows real-time monitoring of Jupiter and Solar storms from UFRO and WCCRO.
Radio-Sky Jupiter Noise Storm Predictions
A Panoramic View of the Big Dipole Array at the UFRO
Windward Community College Radio Observatory - Realtime streaming decametric audio and Radio-SkyPipe strip charts.
Voyager Planetary Science Info (Great for Teachers).
University of Florida Radio Observatory Jupiter sound files and prediction tables.
JPL Radio Observation of Comet Shoemaker-Levy press release.
Another Jupiter recording, and info at a John Kraus site.
Nancay Jupiter Observatory in France Real-time Spectrographic Display
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