Topband: Big 160m openings just before K index spikes

[Nick Hall-Patch]

Hi Mark,

Earlier this year on this list, K9LA posted the following:


>With respect to Wolf DF2PY's comment about very good propagation on polar
>routes when the A index and the solar wind speed are elevated, our
>understanding of what makes 160m tick is lacking. In other words, "stuff
>happens".
>
>Having said that, there have been similar reports of good propagation on
>160m at high latitudes when the K index spikes up. A process that could
>explain this is tied to changes in the E region and lower F region at
>elevated K indices. When geomagnetic field activity increases, the
>atmosphere's electric field (measured in terms of mV/meter) increases. When
>this happens, the electron density valley above the E region peak can
>become better developed (deeper and more vertical extent - which would
>eliminate transits through the absorbing region and eliminate ground
>reflections).
>
>This process comes from a 1984 paper in the Journal of Geophysical
>Research. It is only a model - I'm not aware of any measurements to confirm
>that this happens. So "buyer beware". All I can say is - it makes sense.
>
>Carl K9LA


In addition, it strikes me that there was a recent academic paper 
that said something about ionospheric layers increasing in height at 
the onset of a geomagnetic storm, but darned if I can find a copy of 
that right now.   Does anyone else recall this?

73

Nick
VE7DXR


At 19:37 2017-12-09, Mark Connelly via Topband wrote:
>The "boost before bust" phenomenon has also been noticed by DX 
>listeners of the AM broadcast band.
>
>Here on the US East Coast, some of the more reliable northern 
>European signals are the UK stations on 693, 882, 909, 1089, and 
>1215 kHz.  We used to have the Norway "flamethrower" on 1314 as a 
>great propagation beacon but that station, like many others in 
>northern Europe, has gone dark.
>
>When solar flares occur, radiation travels outward at the speed of 
>light, making the trip in a bit over 8 minutes.  Charged particles 
>are also ejected: these may take a day or so to reach Earth's ionosphere.
>
>The effect of that initial arrival of radiation seems to be enhanced 
>higher latitude northern hemisphere propagation.
>
>As the charged particles start coming in and the A/K indices rise, 
>high latitude routes are attenuated.  In the early evening here in 
>Massachusetts, for instance on 750 kHz, you would go from good 
>reception of a station in Newfoundland (CBGY, Bonavista Bay) over to 
>a channel dominated by a station in Caracas, Venezuela 
>(YVKS).  Northern European signals go away.  If anything is coming 
>across the Atlantic at that point it would be African signals such 
>as Mauritania on 783, Canary Islands on 621 etc.  Mostly a lot would 
>be heard from Latin America.  Brazil, Venezuela, Colombia, and 
>Puerto Rico are quite prominent since many of the more-northerly 
>interferers (US, Canada et al.) are blocked out.
>
>Mark Connelly, WA1ION
>South Yarmouth, MA, USA
>
><<
>Yes Lee I guess we have all seen as in my case enhancement from here to VK
>under those conditions including places like KH0, JD1 etc.
>locals for you guys. However the very best of conditions I have seen is when
>the K index stays very low at 0 or max 1 for several days. Then the big US
>openings can happen and I can end up working all states in a week contest.
>If it times correctly with a contest. Bring it on.
>73 Clive GM3POI
>
>-----Original Message-----
>From: Topband [mailto:topband-bounces at contesting.com] On Behalf Of Lee
>STRAHAN
>Sent: 08 December 2017 17:38
>To: topBand List
>Subject: Topband: Big 160m openings just before K index spikes
>
>I have also seen big openings here in Oregon just prior to a big solar
>event.
>If I recall correctly it was when I worked the A4 which is huge from the
>Pacific Northwest.
>Lee K7TJR
>_________________
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> >>
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Nick Hall-Patch
Victoria, BC
Canada 


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