[na-user] Beam Headings, et al

dap14@daimlerchrysler.com dap14@daimlerchrysler.com
Wed, 14 Apr 1999 10:54:31 -0400

To: NA Users

Here's an update on the recent issues concerning anomalies with beam headings
and these not appearing in WPX.

We owe our thanks to Eric, K6EP whose digging into both of these issues
correctly identified the circumstance when they occur.

ERRONEOUS BEAM HEADINGS - I spent some time last night tracing through the code,
which is a real challenge when you don't truly understand how it works!  (This
is a complicated trigonametric algorithm from a published work referred by N6TR
- heck if I know the theory!)  From what I was able to determine, the code is
working correctly; that is, there are no numeric errors being committed.
However, under the conditions that K6EP pointed out, the code tries to execute a
tangent 90 or 270 degrees which is infinity.  No crash occurs, but I wonder if
this not a limitation of the original algorithm?  I will continue to look into
this, and if necesary we'll go back to the original algorithm (pre-Dec '96).

for this is simple - in WPX a "multiplier" does not exist on the list until it
has been worked.  To put it another way, the multiplier list in a DX contest
exists when you load your file - its countries from 1A0 to ZL9.  In WPX, mults
are "added" to the list as they are worked.  The way the F10 code works, it
relates the input data to the mult list and if it has been worked, displays the
results.  With an unworked prefix, there are no results.  Simple.

Fixing this proved to be fairly simple.  For WPX, the country calculation WAS
being made, but if no multiplier was found the country ID was thrown away.  Some
minor logic restructuring fixed this, and now the beam heading and
sunrise/sunset times will be appear whether the prefix has been worked or not.

I've also found some cosmetic bugs in the score window in certain contest
formats, resulting from recent modification to ensure that we could accomodate
five-digit QSO totals (we should be so lucky!).  Anyways, there will be a 10.38
out soon.  Its not likely that I can fix the erroneous beam headings by then,
but we WILL keep working on this.



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