-------------------------------------------------------------------------------- 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.