BIRO Spectrograph Files

April 29, 2008 UTC

The following images are from an Io-B storm observed at the Big Island Radio Observatory by Jim Sky.
Longitude: 155.75 W   Latitude: 19.2 N
Receiver: SDR-14
Antenna: 8 element wire Log Periodic
Software: Modified version of the Radio-Sky Publishing Spectrograph software.

Times are in UTC. Conditions were relatively quiet for this observation, however there were some periods where the background noise level was enhanced by some sort of broadband interference.  The earliest bursts heard while listening at 20.1 MHz on a Jove receiver were L bursts. Later in the storm S bursting seemed to dominate. Disappointingly, these SDR-14 images do not reveal (at least yet) a distinct difference in appearance for S and L bursts the way the WCCRO and UFRO spectrograph instruments do.

Io B emission was immediately evident around 15:00 UTC, suggesting that this observation should have begun sooner.

Ascent of upper band measured at +7 kHz / second.

Enhanced background level begins near the end of this image.

Interference temporarily abates about 15:39.

Note that the emission is often present in two bands separated by about 4 MHz. One possible explanation is that there is a harmonic component. Could it be that the fundamental emission occurs at about 4 MHz and if free of our ionosphere we might see more harmonics? Could these be the 5th and 6th harmonics?

Descent of upper band measured at -8 kHz /second.

CBer signal appears above 27 MHz.  The Sun has risen in Hawaii.

Interference evident as sharp boundaries at the beginning of this image.

Last emissions appeared on this image though monitoring was maintained until 1700 UTC.