[CQ-Contest] INFO: ITU zone overrides in country files

Jim Reisert AD1C jjreisert at alum.mit.edu
Wed Oct 9 16:53:24 EDT 2013

Hi Folks,

There were a few incorrect ITU zone overrides in the country files I
just released:


To review, here is the methodology I use for adding USA stations to
the country file, when they live outside the CQ and/or ITU zone based
on the call area of their callsign:


As you can read above, I have been using USA state boundaries to
determine the CQ and ITU zones.  CQ zones break nicely along state
boundaries, but ITU zones do not.  For example, the eastern parts of
Montana, Utah and Arizona straddle two ITU zones (both 6 and 7).  In
the most recent country file release, I changed the default ITU zone
for a few of these states, based on where I think the greater
population lives.  And of course, this caused some new errors to

To correct this, I enhanced the program to reference a ZIP code
database that contains latitude/longitude for each ZIP code. I use the
geographical coordinates provided by this database (and your ZIP code
as shown in the FCC database) to determine which side of the 110 deg.
W or 90 deg. W longitudinal line you (really, your ZIP code) live on.
Obviously, you don't usually live where the ZIP code says you do, and
it doesn't work for P.O. boxes, so this isn't a perfect solution, but
probably solves 99% of the problems.

As a result, some calls were added, some were changed and others were
dropped from the country file.  As an example, one callsign whose FCC
ZIP code is 63673 was dropped from the list.  The database I have
shows this ZIP code at 89.977 degrees W longitude, or just on the side
of the line where no zone exception is needed.  A back-of-the-envelope
calculation puts this ZIP code about 1.5 miles from the line of 90
degrees W. longitude.  So in fact, depending on where this ham lives,
the program could still give the wrong answer.

Bottom line, if there is an incorrect (or missing) ITU zone override
for you in the NEXT country file release, please bring it to my
attention so I can make the correction.  After all, IARU HF is only 9
months away! :-)

Thanks to Eric K7ABV for bringing this to my attention.

73 - Jim AD1C

Jim Reisert AD1C, <jjreisert at alum.mit.edu>, http://www.ad1c.us

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