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Re: Topband: Big 160m openings just before K index spikes

To: Mark Connelly <>,
Subject: Re: Topband: Big 160m openings just before K index spikes
From: Nick Hall-Patch <>
Date: Sun, 10 Dec 2017 02:42:30 +0000
List-post: <>
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

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

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?



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 [] On Behalf Of Lee
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
If I recall correctly it was when I worked the A4 which is huge from the
Pacific Northwest.
Topband Reflector Archives -
Topband Reflector Archives -

Nick Hall-Patch
Victoria, BC

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