Listening for Jupiter


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Steve’s workstation including ham radio and software-defined radio (2016)

A first attempt at radio astronomy. Since I am a registered ham radio operator (FCC General class), I might as well put the radio to use on listening to the cosmos besides terrestrial communications. I have been reading up on radio noise from Jupiter within the 18-22Mhz frequency range, and my radio can access that range, as this is within the 17 and 15Meter amateur radio bands. No results yet, I have yet to find that noise… Anyhow, here is a link to the radio noises recorded from Jupiter by NASA.

So what do the signals sound like? There are two distinct types: L-bursts sound like
ocean waves breaking up on a beach, and S-bursts, which can occur at rates of tens of
bursts per second, sound like popcorn popping or a handful of gravel thrown onto a
tin roof.
Have you heard them? Late at night is the best time, when the ionosphere has become
transparent and most terrestrial signals have disappeared on the 15 meter band. The quiet
hiss in your headphones comes mostly from relativistic electrons spiraling in the galactic
magnetic field. L-bursts and S-bursts are heard above this background noise. A radio
noise storm of L- or S-bursts can last from a few minutes to a couple of hours (Figure 1).
Do you need a giant antenna spread out over several acres? Fortunately not — a ham
band Yagi will do very nicely. Even if Jupiter is 30º or 40º above your horizon, a lowmounted Yagi aimed toward the azimuth of Jupiter will probably have adequate gain. And you don’t need a cryogenically-cooled front end either; your favorite ham-band receiver is plenty sensitive. Just be sure to turn the AGC off, as AGC can severely distort the Jovian noise bursts. Probably the best frequency range is between 18 and 22 MHz, so if you are using a ham-band only receiver, try the 15 or 17 meter bands. Either AM or SSB
modes will work. Just tune for a quiet spot between the stations.
During a good storm, Jovian signals can be easily heard, often several dB above the
background noise. Of course, the bigger your antenna the stronger the signals. The
640-dipole, 26.3 MHz, phased array antenna at the University of Florida would yield signals well over 20 dB above the background (Wallace & Flagg 2010).

Here is a screenshot of Radio-Jupiter Pro: software that predicts Jupiter radio storms.

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Next target: Jupiter!


My next planned target is Jupiter. Not at prime focus either – boring! I will use oculars 25mm, 9mm, and possibly 4mm. This week’s weather is too cloudy and cold. Observing possible the week of April 11th.