Jupiter Io-C and N event on 30 October 2011
This was a mid- to late-evening pass. We used two Icom R-75 HF Receivers, one tuned to 19.475 MHz (LSB), corresponding to the Red trace in the charts below, and the other tuned to 24.229 MHz (LSB), corresponding to the Blue trace. The receivers were connected to the antenna through a multicoupler. The antenna was an 8-element log periodic antenna pointed about 91 degrees true (no tracking was used).
The predicted activity included an Io-A enhanced storm
from 0330 to 0420 and immediately followed by an Io-C enhanced storm from 0420
to 0615. We detected nothing for the Io-A storm and only two brief episodes of
Io-C, one at about 0529 and another at about 0555. During the Io-C activity we
luckily had one of our receivers tuned to 19.475 MHz at which frequency Wes
Greenman reported a narrowband N-event (see charts below for 0555). We detected
nothing at the higher frequency of 24.229 MHz.
We captured interesting W-shaped spectrum activity on a spectrogram at 0556 with SpectraVue software and an RFSpace NetSDR software defined radio. See the 24 October events for a general description of spectrogram. The one below has a frequency span from 17.85 to 21.35 MHz.
The Jupiter Radio Map immediately below is for reference and shows the orientation of the Io-C enhanced source at the observation time. We observed L-bursts during the brief periods of the audio recordings. The charts below show the two brief reception periods of low-level bursting with expanded time scales. All times and dates are UTC. Listen to mono sound files by clicking the Radio SkyPipe charts or the text below them.
At the time of the charts Jupiter was at azimuth/elevation of approximately 108 degrees true and 23 degrees above the horizon.
Click the chart above for a mono audio file corresponding to the red trace (19.475 MHz)
Click the chart above for a mono audio file corresponding to the red trace (19.475 MHz)
Interesting W-shaped spectrum during the Io-C storm as seen in SpectraVue (above).
In the lower part of the Radio-Sky Spectrograph image directly above, a Jupiter N-event can be seen (image courtesy of Wes Greenman, used with permission). An N-event is a so-called narrowband event, apparent from the limited frequency range seen in spectrograms.