
--------------------------------------------------------------------------------
All     2007    News for NTIA/ITS HF Propagation Models (WINDOWS version)
--------------------------------------------------------------------------------

13 Apr  2007   1. Recent analysis discovered a problem with the combination of
                  radio noise algorithm developed by Don Spaulding.
                  This can be viewed at http://www.its.bldrdoc.gov/pub/ntia-rpt/87-212/ .
                  This has precipitated a modification to the Spaulding algorithm which
                  will be submitted to the ITU to update Recommendation ITU-R P.372-8
                  Combination of Radio Noise at the April 2007 meetings. This submission
                  document and a corresponding computer program which can calculate the
                  combination of radio noise can be downloaded from:
                       http://www.greg-hand.com/noise
                  Note that it is a little complicated to compare the output of this 
                  program (gh_noise.exe) with the noise power produced by VOACAP and ICEPAC.
                  This is because of several factors:
                     1. gh_noise produces results in local time at Rx, VOACAP/ICEPAC is UT at Tx.
                        This allows gh_noise to produce exactly the world Fam contours found in
                        ITU-R P.372-8 (and CCIR Report 322-3).
                     2. VOACAP & ICEPAC will include antenna efficiency in noise power.a
                        gh_noise has no knowledge of an antenna.
                        Thus, make sure you use an isotrope for the receive antenna.
                        If you use SWWHIP.VOA, it has an efficiency of -4.8 dB.
                     3. Quite often in HF frequencies, Galactic noise is not included because
                        it cannot penetrate the ionosphere. Thus, you may need to exclude Galactic
                        noise when using gh_noise.
                  gh_noise allows the calculation of radio noise to be done three (3) different ways:
                     1. "new" modified Spaulding algorithm
                     2. Original Spaulding algorithm
                     3. Simple power sum (used in REC533)

                  For most HF users, very little difference will be noticed, especially above 7 MHz.
                  Most differences will be found at lower frequencies when low levels of Man-made
                  noise are selected (remote and below). In these cases, the new noise calculation
                  will be slightly higher than those previously.

                  I have left a way to temporarily compare the two algorithms.
                  In the Point-to-Point model, if you set the year to 2089, it will use the 
                  original Spaulding. Otherwise, the modified Spaulding will be used.
                  By the year 2089, I assume this program will no longer be in use. :)

15 Apr  2007   1. The previous version had a bad version of REC533.
                  I had been making changes to REC533 as per a request by the ITU, but 
                  problems arose and I had to wait for further clarification.
                  That will take a while, so I have gone back to before making the changes.
                  Sorry for the problem.

13 May  2007   1. The previous version of ICEPAC had bad calculation of SNR 
                  for Es (sporadic E) modes. That has been corrected.

               2. All the main input windows now have the version in the window title.

17 May  2007   1. There was a problem using the OVERLAY option in area coverage 
                  if you used a 70x70 size grid file. I could not figure out 
                  why 70x70 does not work when all others seem to work.
                  I have disabled the ability to use 70x70 grid sizes.
                  I would never use a grid size that is a multiple of 10.
                  Add 1 to it. The cell size is the X or Y range divided by (NGRID-1).
                  Thus, for the whole world, NGRID=61 makes
                       x_cell_size=360/60=6 degrees
                       y_cell_size=180/60=3 degrees
                  NGRID=91 would also be good:
                       x_cell_size=360/90=4 degrees
                       y_cell_size=180/90=2 degrees

03 Sep  2007   1. VOACAP and ICEPAC point-to-point programs had a problem
                  when running Run/Graph with Method=30 and multiple groups.
                  Only the first group used Method=30, the rest of the 
                  groups used Method=20.  This has been fixed.

               2. Two new Man-Made noise levels have been added, Noisy & Quiet.
                  The following are the 6 available levels:

                   Level  Model         Equation              Value @ F = 3MHz
                      1 = Industrial  = -27.7Log(F) + 76.8 = -140.4 dBw/Hz
                      2 = Residential = -27.7Log(F) + 72.5 = -144.7 dBw/Hz
                      3 = Rural       = -27.7Log(F) + 67.2 = -150.0 dBw/Hz
                      4 = Remote      = -28.6Log(F) + 53.6 = -164.1 dBw/Hz
                      5 = Noisy       = -37.5Log(F) + 83.2 = -138.7 dBw/Hz
                      6 = Quiet       = -29.1Log(F) + 65.2 = -152.7 dBw/Hz

                   For some reason in 4/13/07 I changed the value for Remote
                   from -28.6 to -27.7. I cannot remember why I did that, but
                   I have a comment that says I did it to match the ITU report.
                   But the latest ITU report has the value at -28.6.
                   So I changed it back and made these values more explicit
                   in the code and the Help information.

16 Sep  2007   1. I forgot to add a file in the install (..\database\fof2var.txt)
                  that is required by REC533. This is the only change.

21 Sep  2007   1. Somehow the "Swap Tx-Rx" button no longer worked
                  in the Point-to-Point input window. After looking at
                  the problem, I don't know how it ever worked.
                  It has been fixed.

25 Oct  2007   1. This change only affects REC533.
                  REC533 would fail with a division by zero at the North
                  pole when the transmitter was far enough away to require
                  the long path model (FTZ) to be run. 
                  This would occur if you used the Area Coverage over the
                  whole world and the transmitter was below the equator.
                  This has been fixed.

28 Dec  2007   1. A transparent change was made to VOACAP.
                  Someone pointed out that the goemagnetic north pole moves
                  and he wants to see what affect moving the pole has.
                  The geomagnetic north pole coordinates (glat, glon) were
                  fixed in subroutine geom at (78.50N, 69.00W).
                  These coordinates are now located in the file:
                     ..\database\north_pole.txt
                  If this file does not exist, the location (78.5,-69.0) is used.
                  For a user to change this, he should copy the file:
                     ..\database\north_pole.txt
                  to:
                     ..\run\north_pole.txt
                  and then change the first record of this file.
                  The file in the "run" directory will override the file in the
                  "database" directory.
                  Remember that it is your responsibility to remember which
                  output file corresponds to what values of (glat, glon).
                  There is currently no information in the output file indicating
                  the (glat, glon) values.
                  It is recommended that no one change this location without
                  knowing what they are doing.

                  Documentation about this change is found in the file:
                    ..\database\north_pole.txt

                  This change has not been made to ICEPAC or REC533.

