Topband: Good Conditions

kq2m at kq2m.com kq2m at kq2m.com
Wed Jan 11 11:27:36 EST 2023


Thanks for posting that article Patrick.

Another HUGE factor is the Bz  - as Bz drops below zero, the Earth's 
interplantary magnetic field orients South and becomes more susceptible 
to energetic particles which can lead to aurora.  As Bz rises above zero 
the Earth's interplanetary magnetic field reverses to North, the 
opposite occurs, and cndx improve noticeably - especially on the high 
bands, but also impacting 40 -160.

Changes in the Bz orientation and magnitude can occur very rapidly, in 
seconds to minutes with very dramatic changes in propagation.  In 
CQWWSSB 2021 I was noticing many 2 - 5 s-units swings in signal strength 
in seconds to a few minutes on 10 and 15 all weekend.  Like someone was 
rotating the AF Gain knob back and forth on their radio!

There were similar but less dramatic swings in signal strengths on EU 
signals on 40 - 160 over extremely short time periods as the Bz moved 
from negative to positive and back again.   These signal strength 
changes were not the usual QSB.

I'm sure that if Carl were updating his article in 2022 (his original 
article written in 2008) he would include Bz and discuss its importance. 
  Bz direction and magnitude is one of the more important factors in 160 
propagation as well as on 80 - 10.

73

Bob, KQ2M



On 2023-01-11 08:36, W7TMT - Patrick wrote:
> Lower solar wind speed perhaps?
> 
> Carl, K9LA has an interesting article linking solar dynamic
> pressure/solar wind speed to 160M propagation predictions.
> 
> It is found here:  https://k9la.us/Predicting_160m_Propagation.pdf
> 
> Based on the historical data for the last 7 days found on the NOAA
> Space Weather Center site it appears that the wind speed numbers have
> been trending down, with the exception of a cluster of short spikes,
> over the last few days of reported improved propagation.
> 
> The historical data can be viewed here:
> https://www.swpc.noaa.gov/products/real-time-solar-wind
> 
> Patrick. W7TMT
> 
> 
> -----Original Message-----
> From: Topband <topband-bounces+w7tmt=outlook.com at contesting.com> On
> Behalf Of Roger Kennedy
> Sent: Wednesday, January 11, 2023 03:32
> To: topband at contesting.com
> Subject: Topband: Good Conditions
> 
> 
> As someone commented, maybe we should complain about poor conditions
> more often, as the band was in good shape for DX last night!
> 
> I came on for a while from around 0300Z, and worked 22 NA stations in
> 18 different States . . . best DX was Texas.
> 
> Good to hear so many stations on 160m, both sides of the pond.
> 
> I'm still suffering with a high noise level, so apologies if you were
> one of the stations calling me that I couldn't quite copy. OFCOM have
> shut down one of my local noise sources . . . they are coming back up
> here tomorrow to hopefully shut down the other one. (they have located
> the source, but the offending business was closed)
> 
> 73 Roger G3YRO


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