31 July 2006    News for NTIA/ITS HF Propagation Models (WINDOWS version)

31 July 2006   1. A user running the software on a Linux system with Wine
                  reported a problem in VOACAP area coverage calculations.
                  This was traced to floating point underflows that Windows
                  systems let pass. But Wine caused execution failure.
                  I was able to track the problem to the evaluation of the
                  geographic variation of the long term prediction maps in
                  the subroutine VERSY. This was eliminated with some well
                  placed double precision calculations. Similarly, REC533
                  had problems in subroutine EVLGOG.  I have been unable to 
                  solve the problem in ICEPAC. Thus, ICEPAC may not run under
                  Linux with Wine.

               2. Actually, I spent 8 hours on 31 July solving the ICEPAC
                  underflow problem. It was quite a bit more complicated.
                  Thus I am re-releasing with the ICEPAC change and I
                  am removing the 30 July 2006 version.

               3. Jari requested an option in the Point-to-Point interface
                  to allow the Tx and Rx coordinates to be swapped.  Thus,
                  you will notice a new button to perform this task.
                  If you have a directional antenna, it will NOT swap the
                  mainbeam azimuth.