On 07NOV13 there was a
Sudden
Ionospheric
Disturbance which was captured by three amateur receiving stations:
G4JVF VLF receiving NAA on 24 kHz
W4HBK grabber on 10m receiving G0PKT
W5COV receiving WWVB
This is a comparison of the exact timing of the onset of the SID as seen by the three observers.
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| G4JVF VLF RX Receiving NAA in Maine |
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| W4HBK 10m Grabber Receiving G0PKT |
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| W5COV VLF RX receiving WWVB in Colorado |
I measured the times on the first two by measuring distances with a ruler and interpolating. Marks estimating the onset were placed first and then the measurements taken. On the last image since the SID wasn't clear to me I calculated the time estimate from the first two and placed that on the figure. As I understand it's one of the small spikes.
For comparison here is the X-Ray flux measured by the GOES satellite:
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GOES X-Ray Flux for 06NOV13 SID
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All things considered the agreement is excellent. At the time of occurrence the Sun was over the Atlantic which would strongly illuminate the skip points for the EU-US path. The W5COV-WWVB path was almost in the dark and might be expected to be minimally effected by the SID.
Previously with SIDs I had gotten the impression that the QRSS method was more sensitive to the onset time than were other methods. But now that I have seen them together and put some numbers with onset features it looks like there is no significant difference.
de w4hbk
