Topband: low band propagation at solar min

[Yuri Blanarovich]

There appear to be different propagation patterns during various sunspot 
cycles.

 From my article in CQ Magazine June 1980:
http://www.k3bu.us/propagation.htm


> It is known that with increased sunspot activity  the thickness of the 
> atmosphere increases. (This caused Skylab to come down  prematurely). 
> This also increases the height of the propagating layers and 
> therefore increases the height and length of the "arches", it allows 
> us to span  longer distances and extends propagation later into the 
> night.

We have been told that during peaks of solar  activity the lower 
frequency bands are very poor, mainly because of attenuation  of the D 
layer of the ionosphere. On the contrary, the propagation on the low 
bands has been better than what we experienced during the sunspot 
minima. The  40m. band has longer openings to remote areas of the world. 
Eighty meters is the  same; we are hearing Europeans around 6 p.m. local 
time. During the 160m. CQ  Contest I was hearing G stations for about 8 
hours during the night. It appears  again that the refracting layers are 
higher, allowing us to work longer  distances with stronger signal 
levels.

It appears then that with higher sunspot  activity, the average height 
of the media increases, refraction of higher  frequencies improves, 
allowing us to work further and increase the number of  useful 
frequencies for communication. 
<

Area under sunspot cycle count curve would be representative of the 
amount of Sun's energy emission over the cycle. Cycles with high 
activity would have "fatter" curve, representing more intense energy 
hitting the Earth, atmosphere and ionosphere heights increase, 
(atmosphere gases expand) and propagation layers increase height. The 
result is that sunspot minima between "fat" more intense cycles are 
different, they are shorter and with layers at higher altitudes. Minima 
between or after low cycles are longer and layers are at lower heights, 
changing propagation paths, shorter openings.

There is also hysteresis - flywheel effect where the effects are 
shifted, delayed as we see in shift in Earth temperatures (coldest days 
are not the shortest days, but shifted.)

To summarize, it appears that best top band propagation happens during 
sunspot minima at high sunspot activity cycles. Other variables, layers, 
absorption, Earth angles make top band propagation so unpredictable, but 
there is a pattern to it. "You gotta be there when it happens!"

This has effect on weather patterns too, where low sunspot cycles cause 
atmosphere (gas) to shrink, becomes more dense and weather patterns 
change, hurricanes, tornadoes etc. Global whatever, not our SUVs.
I hope K9LA gives me credit for this explanation and record, unlike 
denying my pointing out high angle propagation on top band.

73
Yuri Blanarovich, VE3BMV, K3BU.us
topbanding since 1958


 
 On Sun, Jun 05, 2016 at 07:21 PM, John Kaufmann wrote:
 
 > (Note: disregard my earlier incomplete post)
>
> Carl K9LA:  " But in my opinion (and in the opinion of others) the 
> deep and
> long solar minimum between Cycles 23 and 24 (2006-2010) didn't live up 
> to
> this axiom compared to the not-so-deep and not-so-long solar minimum 
> between
> Cycles 22 and 23 (1995-1997). It suggests that all solar minimums 
> aren't the
> same."
>
> I will continue the comparison by saying that the solar minimum in the
> mid-1980's topped that of the following two decades in terms of low 
> band
> propagation.  Top Band activity in the 1980's was nothing like it is 
> today,
> but despite that I observed many openings into Europe that sounded 
> like a
> 20m opening.  Propagation to mid-eastern and central Asia occurred 
> pretty
> regularly.  I remember hearing 9M2AX on long path much louder than 
> most of
> the Europeans he was working.  JA's were almost a daily occurrence 
> into W1
> during January of 1987.
> I assumed that this was normal propagation for 160 but I have never 
> observed
> anything consistently as good as it was in the 1980's.  Anyone else 
> found
> this to be true?  What was different about the solar minimum in that 
> decade?
>
> 73, John W1FV
>
>
>
> _________________
> Topband Reflector Archives - http://www.contesting.com/_topband
>