k4pi k4pi at bellsouth.net
Sat Feb 2 08:36:18 EST 2008

Thought I would pass this post from the VP6D gang along in case some of you 
may not have read it.  I hear a lot of frustration come out when DX stations 
are asking for EU or JA and they are strong here in the USA.  There are 
reasons that directive calling is used by DXpeditons.

The "check back later technique":

On the lower frequency bands, openings to the most difficult regions of the 
world are more predictable. For example, on 160m we expect Europe to be 
heard from Ducie Island sunset (about 0300z) until the end of European 
sunrise. That opening is only 1 hour for zone 17, about 2.5 hours for zone 
16/20, about 3.5 hours for zone 15, about 4.5 hours for zone 14, and 
finishes at 0800z for Ireland and Scotland. Stations in zones 16, 17 and 20 
will be much weaker that stations in zones 15 or 14. But, when the sun sets 
on Ducie Island, 160m is also open to all of North America, where operators 
are just relaxing in front of the radio in the evening. Of course, North 
America signals on 160m will be MUCH louder than zone 16 or 17 signals.

The logical approach is to ask the North American stations to "check back 
later", near the end of the European opening. At 0730z, very few European 
signals will be left on this band... but we still have over 6 hours of 
propagation to North America... overlapping with 5 hours to east Asia. DXers 
can expect to hear the low band operators asking for Europe until about 
0700-0800z, and announcing every 10 minutes that VP6DX will be ready to 
start working North America at, for example, 0730z. North American DXers 
should "check back later" at the announced time.

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