Topband: Auroral Oval

[Bill Tippett]

Phil, Terry, et al

K5PC:

 >Wow! Take a look at the oval tonight. The red part covers well into the
northern USA. I wonder if you guys up there can see the lights?

         First, here's a direct site for viewing NOAA POES:

http://www.sec.noaa.gov/pmap/index.html

For visual Aurora, this site is not very useful.  The
reason is that "10" on it is only equivalent to about
Kp=5, and Kp goes all the way up to a level of 9, so
it essentially saturates at too low a level to be
useful for visual Aurora purposes:

http://www.sec.noaa.gov/pmap/Intro.html

For visual Aurora, we need Kp of 6 or more in the
continental US (even for Northern latitudes).  Yet
Kp=5 and Kp=9 are identical 10's on the above plot.

http://www.sec.noaa.gov/Aurora/globeNW.html



         For radio purposes, I find the following sites
are much more useful:

1.  What the geomagnetic field *was* (past 3 days):

http://www.sec.noaa.gov/rt_plots/kp_3d.html

Note that Kp was never above 3 the past day which
is why conditions were not very disturbed here.

2.  What it *will be* 30-90 minutes in the future (based
on satellites monitoring solar wind before it hits Earth):

http://sec.noaa.gov/rpc/costello/pkp_15m_24h.html



         Conditions were not so bad here last night
but activity seemed low (maybe EU was asleep so
they could get up early to look for XF4DL).  One
interesting thing was that EA3JE was S9+20 dB on
my vertical array but S7 on my inverted-V.  This
indicated the angle of arrival was very low.  In
large disturbances, angles will go very high.  On
August 20, EA3JE was S9+30 on the inverted-V and
much weaker on the vertical.  Ap hit 38 which is
equivalent to a Kp of 4-5.  Incidentally, K6OY in
California worked Lou on SSB that night, and we
all know how well Lou normally hears.  ;-)  So
disturbed conditions can sometimes actually help.

                                 73,  Bill  W4ZV