Discussion in 'Amateur Radio News' started by VE7DXW, Dec 8, 2020.
This is what Pt. Arguello recorded
Yes, essentially the same - red line is completely within variability of the previous 5 days (green) = no storm effect. (Red has obvious outliers between 19 and 22 UTC.)
What do the spikes represent?
Ionograms are analyzed by software to extract things like f0F2, and these values then are piled up to make the time plot. The software is not perfect, although it does a very good job overall.
Consider: each spike is only a single point on the graph. That immediately raises worries. Geophysical variability is governed by diffusion, transport, production, and loss equations, and numerical scales for variations are not even close to being that fast. If you went back and had a trained expert evaluate each individual ionogram through that period, they would be identified as measurement outliers. Without seeing the input ionograms, I think some kind of RFI came along and fooled the algorithm.
Occam's razor points to these as instrumental artifacts, even without manually inspecting each ionogram. Port Arguello is station PA836 in the UM Lowell digisonde network, so they would give the final verdict if needed.
Why was there no or only a weak solar storm:
Spaceweather.com might have the answer. Turns out we were saved by the fact that the magnetic field that extended with the CME was pointed north. That amplified the earth magnetic field and deflected most of the particles around the planet.
Check the website for more info...
You can get the input ionograms here. The site is a little slow though.
Looks like there's quite a bit of interference on the Port Arguello ionograms at that time.
Swing and a miss. NASA, NOAA, and the experts were way off on this one. NOAA's predicted maximum was G3=Kp7 SEVERE geomagnetic storm. Actual maximum was Kp4 ACTIVE conditions.
You can't always trust the "experts" to be right, even with all their data, models, simulations, and predictions.
Someone who did get it right was the author of this excellent 2005 presentation (a HAM) about solar weather and its effects on amateur radio: https://www.qrparci.org/resource/FDIM81.pdf
This link is also included on the page https://www.swpc.noaa.gov/impacts/hf-radio-communications
See the last page, figure 17, which indicates that for a C class solar flare with earth bound CME, the resulting geomagnetic storm a few days later would be between ACTIVE and MINOR.
This is exactly what happened in this case. A C7.4 solar flare with earth bound CME on Dec 7, 2020 resulted in a maximum geomagnetic disturbance on Dec 10, 2020 of Kp4 (ACTIVE).
Paging through the ionograms around the time of the first spike (~19 UTC) is illuminating. It confirms that RFI got bad enough to fool the F2 peak algorithm for a single record.
Observing from FL there was a significant 28 Mhz band opening late into Friday evening and seen again upon awaking at sunrise today (Saturday) which peaked near midday.
It appeared to be typical Sporadic E layer propagation, signals quickly peaking then taking deep QSB dips. From here on the Gulf coast the range extended mostly from the USA eastern seaboard states and out to the midwest.
However both last night and especially early this afternoon there was a time when QSO's were made within the USA/ Canada from the Southwestern & Rocky Mts states and out to the far west coast (double hop E skip?)
Later afternoon a separate period occurred with transequatorial DX, down into SA, especially Brazil, again not unusual. No DX from Europe or Asia was copied.
Reports from the Upper Midwest (the so called RF Black Hole) indicate they unfortunately had much less favorable propagation, which is typical of when a geo-mag disturbance takes place.
The band is relatively quiet tonight though; just a few scattered "pings" but I did squeek out an extremely marginal contact with one CA station a few minutes ago, with 100 watts & a wire dipole.
Hopefully todays situation at least repeats tomorrow, Sunday.
I can repeat the same observation with my 100w on a 1/4 horizontal dipole at 30 ft. With the broadsides facing south
Only here within EN34, the destination was Southbound with one ping from Argentina on PSK reporter. Otherwise it was a solid skip that was fun to work while it lasted
It took like 10 seconds to appear and 10 seconds to fade when it did
I appreciate the chance for the contacts this past weekend !