[EIDXA] BS7H prop info from K1KD

[Glen and Pam]

I just got this email from son Grant K1KD.  He is active in YCCC and this
seemed of interest.

73,
Glen  K0JGH



Dad,

I'm forwarding an email from someone off the YCCC reflector that talks about
propagation paths from USA to BS7. I've been listening since about 9:30am
local and heard the BS7 start up on 20m cw but signals were very weak this
morning. By 1700z I heard their signal come up on 20m ssb to about s3, but
I've heard them work only JA/EU's since start up. They are going by numbers
on 4's right now on 14.185 up 14.200-230. Good luck!

Grant

----- Forwarded by Grant Kesselring/Burlington/IBM on 04/29/2007 01:38
PM -----

              "David Gerns" <cwdxer at comcast.net>
              Sent by: yccc-bounces at yccc.org
              04/29/2007 07:24 AM


            To
            "'YCCC Reflector'" <yccc at yccc.org>


            cc



            Subject
            [YCCC] BS7 propagation



The last BS7 expedition occurred almost 10 years ago to the day. Since the
SSNs and general conditions are similar, here is the propagation info from
that time.  Might provide interesting guidelines when the mayhem begins:

>From 1997:
Following are the comments of Bob Brown, NM7M regarding propagation between
Scarborough Reef and the eastern half of the United States:
A few bits of data:

#   UT       Radio Flux   Planetary   Largest
#  Date       10.7 cm      A Index    Kp Index
1997 Apr 29      74           8          3
1997 Apr 30      76           8          3
1997 May 01      76          10          3
1997 May 02      76           8          3
1997 May 03      74           8          3
1997 May 04      74           8          3
1997 May 05      74           5          2
1997 May 06      74           5          2
1997 May 07      74           8          3


  Calls           Region         Distance          Path

  W1-W3          NYC area        13,700 km        polar
  W4             Atlanta, GA     14,100 km        auroral zone
  W5             Dallas, TX      13,500 km        sub-auroral
  W8             Cleveland, OH   13,400 km        polar
  W9             Chicago, IL     13,200 km        polar

While the distances are not very different, the paths tell you
something of the problem of making contacts from Scarborough Reef.
Being a low-latitude station, it does well with other low-latitude
locations - JA, VK, ZL, ZS, LU, PY and even W6.  But going to more
northerly sites, the paths become more difficult.

So for the USA call districts shown above, contacts are at the
mercy of geomagnetic activity and whether the solar wind impacts
seriously on the high-latitude field lines.  Any significant geo-
magnetic activity could disrupt the F-region electron densities
(e.g., MUFs) and propagation paths on the higher bands, e.g., 14
MHz, across high latitudes as well as mess up the possibility of
contacts with the USA from BS7.

Right now, the Weekly Boulder Report, "Preliminary Report and
Forecast of Solar Geophysical Data", does not show data in it's
"Twenty Seven Day Outlook" past March 31.  So any idea of possible
geomagnetic activity after that date will have to come later, say
four or less weeks before your April 30 date.  But I will be in
touch and give you the best ideas I can, whether there will be any
geomagnetic disturbance of the polar paths between April 30 and
May 6.

The discussion above has to do with paths; now let's turn to the
frequencies of interest - 40, 30 and 20 meters.  Except for geo-
magnetic disturbances, there will be plenty of ionization to
support propagation of 40 meters.  But actual propagation will be
absorption-limited, paths open when in the dark and D-region
absorption at a minimum.  So propagation programs like MINIPROP
PLUS or Capman should be looked at for times around 1000-1200 UTC
for possible openings.  They will serve you well.

The higher, transition bands, 10.1 MHz and 14.0 MHz, are both
absorption- and MUF-limited.  While there might be brief times in
morning hours when the paths would be open, they are more reliable
at the end of the day, as the sun sets and the F-region decays.
For the paths to the USA, that would be 1300-1500 UTC.  Check your
favorite propagation program for details.

As for long-path, the problems there are the same as above - paths
across polar caps and all those solar wind problems.  Of course,
the greater distances just increase the spatial attenuation and do
nothing to help making contacts.  Long-path is not a winning game
in the present circumstances - stations on the Pacific Coast able
to make short-path contacts even with the idea of the "Aluminum
Curtain".

All in all, my advice right now would be to concentrate on short-
path contacts on 40 meters and venture onto 30 and 20 meters at
the end of a day when there will be darkness on the paths.
Without any serious outburst of solar activity, there's little
propect of chances of propagation on 10 and 15 meters.  Better to
stay on reliable paths and gratify those of the Deserving that are
in attendance.

David, K1LD

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