This contains all NEWS files prior to 1994. 17 Dec 1992 News for NTIA/ITS HF Propagation Models Whenever changes are made to any of the propagation models and a new version is sent, the changes will be detailed in a NEWS file dated the same as the version date. Since this is the first NEWS file, I will discuss a little of the evolution of some of the changes that may already exist in some previous versions. Antennas: Perhaps the one item that has produced the most significant change has been the incorporation of antennas into the propagation models. It was desired to add the CCIR HF antenna package into VOACAP, REC533, and HFBC84. Previously, models such as REC533 and HFBC84 had predefined gain tables for antennas. Thus, when an antenna was chosen, it was valid for all frequencies. VOACAP (i.e. IONCAP) had a different, and more realistic approach. For each antenna entered, a range of valid frequencies was also given. Thus, several antennas can be specified for a given circuit. One valid for 2-9 MHz, another 9-15 MHz, and 15-30 MHz. Each antenna can be of any type, design frequency, main beam direction, etc. To incorporate this ability with the CCIR antenna software became very difficult. The most inner calculation loop in the propagation models is frequency. As you change frequencies, you may change antennas. The CCIR antenna software does initialization the first time you define a new antenna and saves this information to speed up calculations. Since this information would be lost as frequencies change, it became very difficult to implement. I therefore took a major modification to remove all gain calculations from the propagation models. Since these are point-to-point models, once the off azimuth direction is calculated, the only gain values that need to be calculated are for elevation angle. These gain values are calculated for frequencies 2-30 in 1 MHz and elevation angles 0-90 degrees by 1 degree. Further, since one antenna may be valid for 2-9 MHz and another 9-15 MHz, there will be a discontinuity at 9 MHz in this case. A calculation at 8.5 MHz will have no problem. As 9.1 MHz will have no problem. The gains for both 9 MHz are saved. A calculation at 9 MHz will use the antenna 2-9 MHz. There are some major advantages to removing the antenna gains from the propagation models. To add new antennas, the models need not be changed, only the single antenna calculation program. Measured antenna gains can easily be added. Output from other antenna programs such as NEC can be added. By taking this approach, I also stumbled upon a limitation of the CCIR antenna software. To speed up the processing, the CCIR antenna software pre-calculates trig functions. It also truncates the elevation angle to the lower integer degree (very different from rounding). The end result of this is that for an elevation angle of 15.9 degrees, the gain will be calculated at 15 degrees. This can produce quite a difference. By using my external calculation method, I calculate gains at every degree (no problem with rounding or truncation) and then the gain is interpolated in the propagation model. Thus a more accurate result is obtained. While incorporating this new scheme into REC533, I noticed a problem in the E-modes calculations. Since REC533 (and precursor REP894) only ever used gain tables independent of frequency, the use of antenna gain for the E-modes had been removed from the frequency loop to speed up processing. I have corrected this problem and I will notify CCIR of what must be done. The method of defining the antennas is very similar between the 3 models. The only difference is that VOACAP transfers you to a different screen to define the parameters. This perhaps is a bit more difficult, but VOA required an ability to have 10 antennas defined and there was not enough room on the main input screen. In REC533 and HFBC84, I allow a maximum of 5 antennas to be defined, and this is done on the main input screen. Also, VOACAP can mix IONCAP and CCIR antennas. This is not allowed with REC533 or HFBC84, because they have no knowledge of IONCAP! CIRCUITS.DAT This is the data file containing valid Transmitter-Receiver coordinates and antenna information. It should be customized by each user. To accommodate the multiple antennas as discussed above, each circuit may now define multiple antennas. Look at the new format of this file and it should be quite obvious. One problem though, is that this file defines transmitter power for each antenna. However, power (by IONCAP convention) has always been separate from the antenna definition. It is my perception that at a transmitter site with 2 antennas valid for different frequency ranges, even different main beam directions, that they may actually have different power. The users may wish to let me know if they would like power tied to each antenna, or separate as it is. If it is linked to each antenna (hence frequency), then some additional changes in the propagation models will need to be made. BATCH execution This option is selected from the OPTIONS menu after you accept the input data. What it allows is for you to select a sub-set of circuits from the CIRCUITS.DAT data file. This sub-set will then be run using the other parameters defined on the input screen (e.g. month, ssn, system parameters) in a non-interactive GRAPH mode. What this means is it will calculate all frequencies (2-30 MHz) and all hours (1-24) for one month and SunSpot number and produce the graphs for Field Strength, Reliability, and S/N ratio and the table of Field Strength. This will allow you to produce a book of results on an overnight basis. Since this may produce much output and requires an HP LaserJet on LPT1, the actual printing has been commented out of the .BAT file. Thus, to activate this, you need to edit the appropriate .BAT file (VOACAP.BAT, REC533.BAT, HFBC84.BAT) and remove the "rem" from the proper place. Since BATCH is a new concept and I am not yet quite sure how the users wish to use it, I think this is the easiest approach so far. VIEW LAST CIRC I have written a new program called SCROLL that now controlls the viewing of the circuit calculations. This program allows forward/backward and even left/right (for output greater than 80 columns) scrolling of the output files. The arrow keys, HOME, END, PageUP, PAgeDOWN, TAB, and ENTER keys control your movement. The key exits the program. If desired, I could include a capability to search for character strings to greater flexibility. -------------------------------------------------------------------------------- -------------------------------------------------------------------------------- 14 Jan 1993 News for NTIA/ITS HF Propagation Models 4 Jan 1993 changed VOACAP so that when MULTIPATH POWER TOLERANCE or MULTIPATH TIME DELAY are set = 0., multipath probability (MPROB) is not computed. Previously, setting these values to zero caused them to be set to their defaults (10 dB & .85 msec). This was a holdover from the card image format days when a blank value was used to set default values. 8 Jan 1993 changed all RETRIEVE DATA options so that a 1 line summary of the data file is displayed. It includes the file name, Transmitter name, Receiver name, Month, SSN, and Time. 11 Jan 1993 You can now quickly display the CCIR vertical & horizontal antenna patterns to the screen during the antenna selection process. Press the key to display to screen. 14 Jan 1993 Changes made to REC533 calculations as per correspondence with Mike Dick, correcting NOISE and FADING calculations. -------------------------------------------------------------------------------- -------------------------------------------------------------------------------- 22 Apr 1993 News for NTIA/ITS HF Propagation Models 22 Apr 1993 Many changes have been made since the first delivery of this software to accommodate user requests and to make some aspects more flexible. Users may now maintain libraries of TRANSMIT, RECEIVE, and CIRCUITS files. While selecting transmitter or receiver coordinates, pressing the key will allow you to change the name of the file you are selecting from. The names TRANSMIT, RECEIVE, and CIRCUITS are suffixed with a 3 character name of your choosing. Please maintain the .DAT name for the default files supplied. You may also build your data files by inputting the coordinates and names and pressing the to store the transmitter, to store the receiver, or to store the circuit information. These files will automatically be maintained in alphabetical order. Exact duplicates will be removed. Upper/lower case is ignored. You may remove unwanted records with the key. Also new is a vast selection of city coordinates from a geographic data base. Pressing the key while in either the transmitter or receiver fields, allows access to these files. All but one of the files are ASCII and may be added to or new files in the same format may be created. They are located in the ..\GEO directory. Only the file USA_ONLY.GEO is not ASCII and can not be changed. It contains 32028 city names in the United States. The HFANT program has been changed to include a TYPE 11 which is a user supplied gain table versus elevation angle. Currently these values are omni-directional and frequency independent. As the need arises, these features can also be added. For types 5,6,7,10, the directivity gain calculations in the past were not extensive enough, resulting in incorrect results. This has been fixed. Also a TYPE 12 which is a more general set of curtain arrays from NTIA Report 87-215. This allows for non- standard element spacing (e.g. not .5 wavelength). VOACAP has a completely new graphics output program. You are now allowed to plot contours of any parameter on the output file. Thus, selecting different methods, (e.g. 16 thru 23) will allow you to plot different results. The default parameters plotted in the batch more are DBU, REL, SNR, FDAYS. To change these requires a simple change in the VOACAP.BAT files. Also new for VOACAP, methods 11 & 28 will now produce graphics plots on the screen and printer instead of the old line printer graphics with +,*,. symbols. Try it and see if you like it. REC533 still only allows Field strength, Reliability, S/N, and a table of field strengths to be plotted. The cursor can now "wrap" from the top of the input screen to the bottom (using UP arrow), or from the bottom to the top (using DOWN arrow). -------------------------------------------------------------------------------- -------------------------------------------------------------------------------- 18 May 1993 News for NTIA/ITS HF Propagation Models 18 May 1993 VOACAP fixes/enhancements : 1. The following variables have been added to VOACAP: TGAIN - Transmitter gain of strongest mode RGAIN - Receiver gain of strongest mode SNR90 - Signal-to-Noise ratio attained 90% of time. DBM - Power Density (dBu - 30) They may be printed with METHOD 20 (all parameters), or by using the METHOD 23 modifications below. 2. Using METHOD 23 of VOACAP, you may now choose the order and number of variables sent to the output file. The other methods are unaffected. Read the HELP window for the METHOD parameter. 3. Median/Lower Decile S/N parameter removed because of new parameter SNR90 from above is calculated. To plot this parameter, either select METHOD 23 and choose SNR90, or select METHOD 20 (all parameters). 18 May 1993 VOACAP & REC533 fixes/enhancements : 1. BEGINNING/ENDING HOURS may now wrap around midnight. You may now specify hours 22 to 04. Previously, this would have produced hours 04 to 22. 2. MONTHs & SUNSPOTs are now taken as pairs. This was a major departure and very important to frequency planners. To run testing such as benchmarks, you are allowed to make 12 pairs. 3. The NOISE parameter was changed to avoid math errors. You now specify either levels 1,2,3,4 or -dBW values in the range [100 to 200]. Levels are no longer negative and you cannot specify -dBW values below 100 as these were deemed inappropriate. 4. A few problems were corrected concerning the Geo city database files. The major problem corrected had to do with the amount of memory required to access the .GEO files. This has been reorganized and should cause no more problems. 5. The TRANSMIT.*, RECEIVE.*, CIRCUITS.* files no longer reside in the DATABASE directory. Since they have become user specific data files, they now will have their own sub-directory called USERDB. This should make it easier for users to maintain. 18 May 1993 REC533 fixes/enhancements : 1. The contour plotting for REC533 has been converted to the same as VOACAP. -------------------------------------------------------------------------------- -------------------------------------------------------------------------------- 24 May 1993 News for NTIA/ITS HF Propagation Models 24 May 1993 VOACAP & REC533 fixes/enhancements : 1. Whenever you view a CIRCUITS.??? file (either in choosing circuit coordinates or in BATCH selection), you now can view all of the parameters associated with each circuit. Previously, you could only see the lat/long/name of transmitter & receiver. Now you can see all of the antenna parameters. 24 May 1993 HFANT fixes/enhancements : 1. Type 10 (Vertical Monopoles) now save the vertical gain pattern for frequencies 2-30 MHz. Since this is an omni-directional antenna, the horizontal gain pattern is not necessary. This is saved because vertical monopoles have a large overhead during initialization (i.e. when the frequency changes). Thus during propagation calculations, too much time was lost. 2. Dipole arrays (type 1,2,3,4,8,9) are not valid below the frequency ratio .7 or above 1.4. Frequency Ratio (Fr) is Operating/Design Frequency. In the propagation models, if you specify a design frequency (not 0.0), for any operating frequency outside these limits, the gain will be -30. If you specify the design frequency=0.0, the design frequency will be set to the operating frequency. This allows studies to be done when you do not know all of the antenna information. -------------------------------------------------------------------------------- -------------------------------------------------------------------------------- 09 Jun 1993 News for NTIA/ITS HF Propagation Models 1. Antenna types 5 & 6 (Horizontal & Vertical Log Periodic) have been changed to allow up to 30 (from 20) elements. 2. Under advisement from Keith Edwards and Mike Dick, the useable frequency range for Vertical Monopole (Type 10) is now limited to [.05 to .35 times the wavelength]. What this means is .05*300/Height of monopole in meters to .35*300/Height. Frequency is in MHz. 3. Antenna type 1 (Multiband Aperiodic) is limited to the Frequency Ratio (Fr=Operating/Design) of .7 to 1.4. Antenna types 2,3,4,8,9 are limited to .85 <= Fr <= 1.2. 4. Corrections to the Atmospheric Noise variability with frequency have been made. The routine GENFAM in both VOACAP and REC533 was incorrect. The change will probably not be noticed because ManMade Noise is dominate at the HF frequencies involved. Occasionally you may notice a 1 or 2 dB change in SNR and N DBW. -------------------------------------------------------------------------------- -------------------------------------------------------------------------------- 09 Jul 1993 News for NTIA/ITS HF Propagation Models 1. ANTCALC has been modified to now create a FORMATTED file rather than an unformatted one. This should allow you to create your own antenna file with any compiler and not have a read error in the HF model. -------------------------------------------------------------------------------- -------------------------------------------------------------------------------- 14 Jul 1993 News for NTIA/ITS HF Propagation Models 1. ICEPAC has been added as a model. 2. With ICEPAC, you can make short term predictions by specifying current foF2 values at known lat/long/time locations. The program will calculate an "effective" SunSpot Number, and you can use this "instantaneous" SSN to make the predictions for the next hour or so. Anything beyond a few hours should be suspect. -------------------------------------------------------------------------------- -------------------------------------------------------------------------------- 20 Jul 1993 News for NTIA/ITS HF Propagation Models 1. ICEPAC BATCH mode has been fixed. 2. a NEWS.BAT facility has been made to allow easy viewing of all the NEWS files. 3. HFBC.BAT has been updated to include access to the NEWS.BAT batch file. Just type in HFBC and you have access to all of the propagation programs on your system, HFANT, and the NEWS facility. -------------------------------------------------------------------------------- -------------------------------------------------------------------------------- 08 Oct 1993 News for NTIA/ITS HF Propagation Models 1. This version of VOACAP (called 93.1001) has now been benchmarked against the VOA NRL version 93.04 distributed at IES 93 in Washington, D.C. Differences were originally discovered because of 2 reasons. First, the FORTRAN compiler used uses 80-bit registers for intermediate results. When that was changed to save in 32-bit registers, the results matched. Second, 93.04 uses what has been found to be an incorrect noise routine (GENFAM). When this noise routine was inserted, results between 93.1001 and 93.04 were identical (within allowed tolerances). The version now employed, is called 93.1001, and includes the corrected noise routine GENFAM. You may therefore expect differences in the results for frequencies above 10MHz. Frequencies below 10MHz should be unaffected. 2. An error was corrected in the geographical data base search routines. Previously, if you specified a NATION or STATE to search for, and you gave a name that did not exist, the program would abort. -------------------------------------------------------------------------------- -------------------------------------------------------------------------------- 05 Nov 1993 News for NTIA/ITS HF Propagation Models 1. Area coverage calculations and plots has been added to VOACAP, REC533, and ICEPAC. Since the inputs are different, these are controlled by 3 new .BAT files (VOAAREA.BAT, RECAREA.BAT, & ICEAREA.BAT). To access all models installed on your system, execute ITSHFBC.BAT. This will detect which programs exist and display a menu for you to select from. 2. New self-extracting files are now being supplied. READ.ME - describes point-to-point models HFBC1.EXE - general files for all models VOAPK.EXE - specifics for VOACAP point-to-point RECPK.EXE - specifics for REC533 point-to-point ICEPK.EXE - specifics for ICEPAC point-to-point RDAREA.ME - describes area coverage models WORLD.EXE - world political data base for plotting VAREA.EXE - additional files for VOACAP area coverage RAREA.EXE - additional files for REC533 area coverage IAREA.EXE - additional files for ICEPAC area coverage 3. The current version of the appropriate propagation model is now listed on all plots (point-to-point & area coverage). This should avoid probelms if the results change. You will know which version was used. The current naming convension of the versions for the different models is: VOACAP - Version 93.1001 (Year.month_day) REC533 - ITS VER-1.43 09.Jul.93 ICEPAC - Version ITS.01 (Numerical number only) -------------------------------------------------------------------------------- -------------------------------- End of 1993 ----------------------------------- --------------------------------------------------------------------------------