Plots include data from yesterday and today. Check the time (select UTC, 24-hr) to see where the new data is being recorded. There is usually a noticeable discontinuity where the new data ends and the old data remains.
Points are plotted every 10 seconds for 24 hours and the chart is updated every 5 minutes. There are a total of 8,640 points on the graph. (See the new Dataq spreadsheet)
(Based on your computer's clock. Chart displays yesterday's data after time above.)
Black = linear, Red = logarithmic (off)
The plot is from the Oddball Sid Receiver. SIDs will cause spikes between about 12:00 and 0:00, where the plot is normally low. The high portion between 0:00 and 12:00 is nighttime sky wave. The width of the SID window is a function of the season. The logarithmic plot is arbitrarily offset and scaled. The scale is approximately 2 dB per small division.
To confirm a flare, see http://www.swpc.noaa.gov/today.html#xray . For a six hour close-up view, see http://www.swpc.noaa.gov/rt_plots/xray_1m.html.
If the signal drops to zero suddenly, WWVB may have gone off the air; Check the NIST website to confirm.
These SID charts are most useful during the daylight hours but during winter they become a little harder to read at this location. Below is a plot made on 10/25/2013, ending at 23:00. The plot between about 22:00 and the next day at about 12:00 is dominated by nighttime effects and is not very suitable for SID monitoring (and this is only October). Also, during a flare the WWVB signal actually decreases in amplitude before it increases during the winter months here in Austin. As the day progresses it's not uncommon for the signal strength to grow sufficient to make flares hard to distinguish from the rising signal (see the "normal" peaks that are not related to a flare). Note how the M1.9 is barely above the natural rising of the signal level as the sun drops. The "give-away" is the sudden drop in amplitude.
The summer plots are absolutely perfect in Austin!