Hi all
I am including all the replies I got to my original posting.
In summary people have observed the difference in propagation but no one
actually came up with a conclusive answer.
Could it be a temperature related phenomena since the F2 density is related
to temperature and more dense in winter due to the temperature it
propagates higher freqs better ?? and the temperature distribution seems
worse (sorry lowest !!) in jan & feb ??
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Original Posting
perhaps I am making a wrong assumption here but is the propagation to the
northern hemisphere more favourable in Jan and feb rather than Nov Dec ??
I have the impression (perhaps misguided) that the propagation for those in
the north ie EU, JA & NA is at its best in jan and feb ie after the winter
solstice than before ??
Is there such a thing as ionospheric lag (ie similar to thermal lag ) or is
it just a demographic input that amateurs are more aware of propagation,
have more spare time, more tied to the shack than before the Xmas period ??
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Subject: Re: Topband: Seasonal Propagation
..well seems your correct that propagation improves on more
northernly paths........Example.....the guys South of me in Georgia
etc are hearin JA stations....I have Never heard a JA until December
yet I can usually stilll hear them as late in the season as March/first
part of April.....
John K9UWA
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From: Bernie McClenny <bernie@dailydx.com>
Subject: Re: Topband: Seasonal Propagation
References: <199911051112.GAA11229@contesting.com>
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It seems to me it is much better in January and February.
de Bernie
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From: Carl K9LA <k9la@gte.net>
Subject: seasonal propagation
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I would have to think that the data that Bob NM7M posted to the topband
reflector back on Sept 1 has some bearing on your topic of seasonal
propagation.
Bob showed the distribution of magnetic storms by month for a 125 year
period. The most disturbed months are the equinoxes (Mar/Apr and
Sep/Oct), and the quietest are Jun/Jul and Dec/Jan.
Perhaps demographics has something to do with it, but I'm sure this
magnetic storm data also plays a role.
Carl K9LA
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Subject: Re: Topband: Seasonal Propagation
For the last couple of years, I've been running a receiver which records
signal strength from a couple of overseas MW broadcasters in the 1550 kHz
region, with the assumption that these signals have similar propagation to
those in the 160m band.
>From this data, your observation seems to hold water for the 1997-1998
season, but the results are a fair bit more ambiguous in the 1998-1999
season. If you can read .pdf files or MS Word 6.0/7.0 files, I can send
you a chart of the percentage of mornings in each month that there were
sunrise enhancements observed from one Australian and one East Asian signal
in the 1550 kHz region, and let you come to your own conclusions.
Nick VE7DXR
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From: "Preston T. Smith" <n6ss@northlink.com>
Subject: Propagation & Vert Ant
:
:
:
Yes, I have noticed the same during the 10 years I have been on the
band but only in local morning before sunrise. All my good long haul
contacts (half dozen or so) to 4S7, VQ9, OH7 & zone 18 have taken
place in Jan thru March. Evening condx seem to have the same ups
and downs from October to April. Common sense sez condx a month
before solstice should be same as a month after but that hasn't been
the case here. I haven't read anything in the books about this
phenomena and I've arrived at this conclusion without much conviction.
The level of activity may be a factor too.
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Hope the above is of interest
73
Bob Parkes
S21YP, G3REP,
ex-4S7RPG, A45XF, P29PR, VS5RP
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