Ham Radio 2000 #1

home *** CD-ROM | disk | FTP | other *** search

/ Ham Radio 2000 #1 / Ham Radio 2000.iso / ham2000 / misc / enc11 / ion_hdxt.doc < prev next >

Wrap

Text File | 1995-10-14 | 49.5 KB | 1,003 lines

IONSOUND HDX TURBO (TM) by W1FM VERSION 3.50 SKYWAVE PROPAGATION PREDICTION SOFTWARE FOR AMATEUR, PROFESSIONAL, AND MILITARY APPLICATIONS USER'S MANUAL COPYRIGHT 1995 BY JACOB HANDWERKER / W1FM SKYWAVE TECHNOLOGIES ALL RIGHTS RESERVED The author has made every effort to ensure that this program is correct and accurate. However, no expressed or implied warranty or guarantee of any kind with respect to its accuracy or effectiveness is made. The author will therefore not be liable for incidental or otherwise consequential damages, either direct or indirect, in connection with furnishing of, or the performance of, or as a result of the use of this program. The author does not warrant that the functions of the software will meet your needs or that it will operate error-free and uninterrupted. IONSOUND HDX TURBO is a trademark of Jacob Handwerker / W1FM SkyWave Technologies ***** Acknowledgments ***** The outstanding propagation work of R. Fricker, BBC External Services, U.K., and D. Van Troyen, A. Van de Capelle, and A. Deknuydt, in Belgium is hereby acknowledged. Grateful appreciation is expressed to R. Dean Straw / N6BV, ARRL Senior Assistant Technical Editor, for his professionalism and for his many helpful suggestions resulting from the review of the IONSOUND software programs. INTRODUCTION 1. Ionospheric Propagation Background Radio waves can be classified according to various types of propagation. These propagation types are ionospheric, tropospheric, or ground waves. Ionospheric, also known as skywave, propagation provides the major portion of the overall radiation that leaves an antenna at some elevation angle above the horizontal plane. Much of the short and long-distance communications below 30 MHz depends on the bending or refraction of the transmitted wave in the earth's ionosphere which are regions of ionization caused by the sun's ultraviolet radiation and lying about 60 to 200 miles above the earth's surface. The useful regions of ionization are the E layer (at about 70 miles in height for maximum ionization) and the F layer (lying at about 175 miles in height at night). During the daylight hours, the F layer splits into two distinguishable parts: F1 (lying at a height of about 140 miles) and F2 (lying at a height of about 200 miles). After sunset the F1 and F2 layers recombine again into a single F layer. During daylight, a lower layer of ionization known as the D layer exists in proportion to the sun's height, peaking at local noon and largely dissipating after sunset. This lower layer primarily acts to absorb energy in the low end of the High Frequency (HF) band. The F layer ionization regions are primarily responsible for long distance communications, sometimes in conjunction with the E layer in a variety of mixed propagation modes. Vertical incidence ionospheric sounding devices are used to determine the virtual height of an ionospheric layer at various frequencies by beaming energy upward and measuring the time delay required for the round trip. The critical frequency for a vertical incidence sounder is the maximum frequency above which no energy is returned to earth for a given layer. An ionogram is a graphic representation of such sounding and usually depicts the height of the layer (or the time delay) as a function of the sounding frequency, along with the intensity of the return signal. An oblique sounding device may require the cooperation of a corresponding receiving device at a distant point in order to depict received energy which has been transmitted at incidence angles less than 90 degrees in elevation; it may also make use of backscatter techniques to assess the propagation path. Devices such as these can then be used to assess (in real time) the propagation path frequencies which can be supported, up to and including the Maximum Usable Frequency (MUF). As an adjunct to this Users Manual, it is recommended that other sources of information concerning HF propagation prediction and related antenna theory be consulted since this operating manual is not meant to be a comprehensive tutorial on the theoretical aspects of these subjects. A bibliography of several of these source materials is shown at the end of this manual. 2. IONSOUND HDX TURBO Overview IONSOUND HDX TURBO is a very sophisticated ionospheric propagation prediction program for frequencies between 1.8 MHz and 30 MHz. IONSOUND HDX TURBO is a member of the IONSOUND family of programs which have been evolving for a number of years. Geographical regions corresponding to those shown in ARRL's QST magazine "How's DX?" column can primarily be chosen from the TX and RX location menus along with several others not found in QST. IONSOUND HDX TURBO has been designed with user friendliness in mind and is entirely menu-driven, with prompting for various user inputs to the program. It should be emphasized that a comprehensive understanding of propagation phenomena and the technical terms associated with the scientific forecasting of propagation is helpful, but not necessary, to become skilled in the use of IONSOUND HDX TURBO. The goal of the program is to produce an easy-to-interpret tabular prediction of radio frequency (RF) link performance between two locations on the earth's surface. Technical jargon and output detail has been minimized to essential elements in the interest of simplicity, without a sacrifice in overall performance of the program or its presentation display capabilities. To simplify matters, default inputs have been provided. An explanation of the use of these menus and screens will be provided in this manual, but the program should be largely self explanatory. Once the operator has customized IONSOUND HDX TURBO to suit his/her particular needs, the information is saved to disk as a set of defaults. When the program is started, the operator need only hit the <Enter> key several times to accept the custom defaults and then make a propagation prediction. 3. General Requirements IONSOUND HDX TURBO is designed for use with IBM or IBM-compatible personal computers. The program operates with or without an 8087, 80287, or 80387 math coprocessor. It will automatically take advantage of the coprocessor if it finds it. However, if at all possible, a coprocessor should be utilized, due to the mathematically intensive nature of the calculations performed in the propagation prediction process. Processing times can become lengthy without a coprocessor; in fact, a coprocessor will usually speed up operation by a factor of 15 or even more. Note that the 80486DX and the Pentium processors have the coprocessor built-in, while 80486SX versions do not. If you intend to do antenna modeling and propagation predictions, an investment in a numeric coprocessor is worthwhile. A personal computer with 640 kilobytes of RAM is desirable, along with DOS version 2.11 or greater. For hard copy printout, a printer supporting IBM Graphics is recommended. 4. Printing IONSOUND HDX TURBO Operator Manual You may print out this Operators Manual. First, make sure your printer is on-line, then type the following: TYPE ION_HDXT.DOC > PRN <Enter> or PRINTDOC <Enter> 5. Starting IONSOUND HDX TURBO To start IONSOUND HDX TURBO type the following: ION_HDXT <Enter> For convenience use the batch file: ION <Enter> Following the start-up of IONSOUND HDX TURBO, the program will prompt the user, in a step-by-step fashion, with several screens prompting user responses. 6. General, Menus and Screens All entries, such as for YES/NO (Y/N) selections, can be made in either lower case or upper case. Default conditions for most of the menus and screens are shown by a notation such as: <DEFAULT= #> or <Y> or <N> or <C/Q>. Default= # is the option number which will result if the enter key is pressed instead of actually inputting a number value. Likewise, Y or N defaults indicate YES or NO, respectively. When a <C/Q> option is encountered, the default is C (continue); typing Q indicates "Quit" back to the Main Menu. 7. Display Color Selection There are eight possible color combinations for the display text and background. The program comes up in black and white unless you choose another combination. Caution: a background color other than black will cause a black/white monitor to be unreadable! 8. Transmit and Receive Location The selection menu for transmit (TX) and receive (RX) locations each consist of up to 24 choices. Choices 1-14 allow selection of predefined locations corresponding to those shown in QST magazine's "How's DX?" column, published monthly by the American Radio Relay League (ARRL). Choices 15 through 21 are for additional predefined locations not covered in "How's DX?" Choice 22 allows for input of latitude and longitude for any user-specified location on Earth. Choice 23 allows selection of predefined locations found in the file 'ION_CTY.DAT' or a file of your own choosing. Choice 24 allows the selection of the prior location in choice 22 or 23. [Note: When inputting a user-specified location in Choice 22, the Degree.Decimal format allows decimal fraction degrees (i.e., 39.25 represents 39 + 25/100 degrees); the Degrees.Minutes format allows degrees and minutes (i.e., 39.25 represents 39 degrees + 25 minutes) as an entry.] These selections make it easy to compute IONSOUND HDX TURBO predictions for comparison with the Highest Possible Frequency (HPF), Maximum Usable Frequency (MUF), and the Frequency of Optimum Transmission (FOT) predictions derived from U.S. Department of Commerce, National Telecommunications and Information Administration (NTIA) IONCAP program as found in QST. [Note: Although the "How's DX?" list in QST is limited, it can be successfully used to predict propagation performance between many other locations which are near those shown in Table 1.] Table 1 Expanded List of QST "How's DX?" TX/RX Locations Choice Location Latitude Longitude Nearest City 1 Alaska 61.00 150.00 Anchorage 2 Australia -33.87 -151.22 Sydney 3 Central Asia 28.50 -77.50 New Delhi, India 4 U.S. East Coast 39.00 77.00 Washington, DC 5 Eastern Europe 50.50 -30.50 Kiev, Ukraine 6 Hawaii 21.33 157.80 Honolulu 7 Japan 35.75 -139.80 Tokyo 8 U.S. Midwest 39.00 95.00 Kansas City, KS 9 Caribbean 18.50 66.00 San Juan, Puerto Rico 10 South America -25.00 57.50 Asuncion, Paraguay 11 South Pacific -14.33 170.70 Pago Pago, Am. Samoa 12 Southern Africa -15.50 -28.00 Lusaka, Zambia 13 U.S. West Coast 38.00 122.00 San Francisco, CA 14 Western Europe 51.50 0.20 London, England 15 Central America 15.00 90.00 Guatemala City 16 East Mediterranean 31.50 -35.00 Jerusalem, Israel 17 Indian Ocean -6.50 -107.00 Djakarta, Indonesia 18 U.S. Northeast 42.35 71.05 Boston, MA 19 U.S. Northwest 47.50 122.50 Seattle, WA 20 U.S. Southeast 30.25 81.50 Jacksonville, FL 21 U.S. Southwest 33.50 112.00 Phoenix, AZ Latitude and longitude values are given in decimal degree format. Positive values of latitude (+) are north of the Equator; negative values (-) of latitude are south of the Equator. Positive values of longitude (+) are west of Greenwich, UK; negative values of longitude (-) are east of Greenwich. See QST Magazine, December 1990, Technical Correspondence, Pages 58-59, "Propagation Predictions and Personal Computers" for a discussion of how these locations are used in conjunction with sunspot numbers and minimum elevation angle requirements to derive IONCAP predictions for QST Magazine's "How's DX?" column. 9. Short/Long Path Selection Selection of Short <S> or Long <L> path gives an opportunity to choose either the shortest or the longest great circle path from the transmitting to the receiving location. The default for this selection is the short or S path. IONSOUND HDX TURBO is designed to support only direct paths; skew paths that are not on great circles are not supported. Following the selection of either short or long path, the distance in kilometers, statute miles, and nautical miles from the transmitter to the receiver is provided by the program. Also shown is the front/back (F/B) bearing in degrees (eg, 315 / 135). The front value is the bearing (or heading) direction from the transmitter toward the receiver. The positive value of bearing indicates the clockwise number of degrees offset heading from True North (0 degrees) which a radiated signal will follow on a great circle path from transmitter location to receiver location. The back value is the direction opposite (or 180 degrees away) from the transmitter-to-receiver direction. 10. Receiver Noise Receiver noise code can be independently selected for the transmitter (TX) location and the receiver (RX) location. Since link predictions are always made for the path from the transmitter to the receiver, it makes a difference in predicted performance when the two locations are 'swapped' and the TX receiver noise code is not the same as the RX receiver noise code. Swapping of the TX and RX locations can easily be done from the Main Menu. When this 'SWAP' function is exercised, the respective noise codes are interchanged for prediction purposes, along with the latitudes, longitudes and location descriptions. A choice of three receiver noise codes can be inputted by the user. These choices are CITY, RESIDENTIAL, or RURAL noise. This selection is used in determining the received signal-to-noise ratio. The selection of receiver noise code should be made by considering the geographic location of the TX location receiver and the RX location receiver in relation to city, residential or rural surroundings. Choosing city noise results in more noise at the receiver than residential noise. Likewise, residential noise is less than city noise but more than rural noise. The received noise power density, also varies as a function of frequency at the receive end of the RF link. Lower frequencies have greater ambient noise background levels than higher frequencies. The actual receive noise power (expressed in Watts) depends upon the receiver bandwidth. The default for choosing a TX or RX location receiver noise code is residential noise. 11. Antenna/Gain Selection The Transmit and Receive Antenna Selection Menu allows the operator to choose the antenna for both the transmitter and receiver locations. The selections offered for transmit/receive antennas represent typical candidate configurations for predicting propagation performance. Each is represented by a mathematical model whose gain varies as a function of the elevation angle. Please note that the overall response of each antenna selection is a generic, theoretical response, since real-world effects for an individual location (such as local terrain, other antennas, or nearby power lines) cannot be included. Table 2 TX/RX Antenna Gains vs. Elevation Angle Takeoff Dipole Vertical Yagi Log/Rhom Curtain Isotropic Angle Ant Ant Ant Ant Ant Antennas D V Y L C G I (deg) (dB) (dB) (dB) (dB) (dB) (dB) (dB) 1 -9.37 -3.15 4.89 -4.28 11.72 -40 to +40 0 5 -2.40 -1.21 6.82 2.68 18.68 -40 to +40 0 10 0.54 1.11 9.14 5.57 21.57 -40 to +40 0 15 2.19 2.06 10.10 7.13 23.13 -40 to +40 0 20 3.28 2.16 10.19 8.11 24.11 -40 to +40 0 25 4.04 1.90 9.93 8.71 24.71 -40 to +40 0 30 4.58 1.51 9.54 9.05 25.05 -40 to +40 0 35 4.93 1.02 9.06 9.16 25.16 -40 to +40 0 40 5.13 0.44 8.48 9.07 25.07 -40 to +40 0 45 5.20 -0.25 7.78 8.79 24.79 -40 to +40 0 50 5.13 -1.08 6.95 8.31 24.31 -40 to +40 0 55 4.93 -2.07 5.96 7.62 23.61 -40 to +40 0 60 4.58 -3.26 4.77 6.66 22.66 -40 to +40 0 65 4.04 -4.72 3.32 5.40 21.40 -40 to +40 0 70 3.28 -6.50 1.53 3.72 19.72 -40 to +40 0 75 2.19 -8.62 -0.59 1.41 17.41 -40 to +40 0 80 0.54 -11.33 -3.29 -1.97 14.03 -40 to +40 0 85 -2.40 -16.41 -8.37 -7.91 8.09 -40 to +40 0 89 -9.37 -29.99 -21.96 -21.86 -5.86 -40 to +40 0 Notes on IONSOUND HDX TURBO Antennas: D=Dipole Horizontal or Vertical Dipole, approx. 3/8 wave high V=Vertical Vertical Monopole, ground-mounted Y=Yagi-Uda Yagi-Uda Array, approximately 3/4 wave high L=Log/Rhom Log Periodic or Rhombic Array, approx. 1/2 wave high C=Curtain Curtain Array, wide elevation takeoff angle coverage G=Isotropic Gain -40 to +40 dBi, constant gain at all takeoff angles I=Isotropic 0 dBi, constant gain at all takeoff angles The Yagi-Uda (Y) in IONSOUND HDX TURBO emulates a Yagi mounted approximately at 3/4 wavelength above ground. It has a peak gain of +10 dBi (that is, referenced to an isotropic radiator in free space) at 15 degrees and has essentially no output at very high elevation angles. Most amateurs select the IONSOUND HDX TURBO Yagi model for predictions in the HF bands above 14 MHz, or even 7 MHz if they have a 40-meter Yagi. [Note: Many use the Yagi even for 3.5 MHz just to see how the predictions come out for those lucky hams who do have 80-meter Yagis!] The Vertical Monopole (V) selection emulates the behavior of a ground-mounted vertical antenna over real earth ground. It has a peak gain of 2 dBi at an elevation angle of 30 degrees, with essentially no output near 0 degrees or at very high elevation angles. The upward-tilted elevation pattern for the vertical monopole is broad and usable for low/medium launch-angle coverage. The Horizontal or Vertical Dipole (D) selection emulates a dipole mounted approximately 3/8 wavelengths over ground, with a peak gain of +5 dBi at 45 degrees elevation. The upward-tilted elevation pattern is broad and usable for all-around elevation coverage. Many amateurs use this IONSOUND HDX TURBO dipole selection for the lower HF bands, mostly on 1.8 and 3.5 MHz. The variable gain Log-Periodic and Rhombic (L) selection has been weighted to provide gain ranging from +7 dBi at 1.8 MHz to +16 dBi gain at 30 MHz. The maximum gain is maintained at an angle of approximately 30 degrees above the horizon, again with essentially no output near 0 degrees or at very high elevation angles. This pattern emulates a very large multi-band horizontal Log-Periodic or a terminated Rhombic antenna. At each frequency the height of the antenna is approximately one-half wavelength above ground. The variable gain Curtain (C) Array antenna selection has been weighted to provide a variable peak gain over an isotropic radiator ranging from approximately +23 dBi at 1.8 MHz to +28 dBi gain at 30 MHz. The maximum gain is maintained at an angle of approximately 30 degrees above the horizon. Of course, most 160-meter operators have a hard time achieving any gain at 1.8 MHz, so this curtain antenna provides an upper bound on what is imaginable for antenna gain on all frequencies. In other words, if the band doesn't open up for this antenna, nothing will make HF communication possible! Selection of 'Choose Your Own Gain' (G) provides an opportunity to pick an Isotropic Gain antenna between -40 to +40 dBi. An isotropic radiator is an ideal antenna that radiates uniformly in all directions. The weighting function for this choice provides the same gain at all elevation angles, allowing the program to pick out all possible propagation modes on a theoretical basis, with virtually no limitations due to the use of real antennas over real ground. Most of the time the lowest possible elevation angles are predicted when a high-gain isotropic antenna is used, even on the low frequencies. The selection of any particular antenna or isotropic gain value will cause the program to utilize this gain value for all frequencies. If a particular antenna is suitable at some frequencies but not at others, the program should be rerun with the correct antenna selection if more accurate or realistic results are desired. [Note: The user can use selection 14 from the Main Menu to show the influence of electrical height on an antenna's major lobe and null characteristics and the resulting single hop E and F layer distances.] 12. Receiver Bandwidth The selection of a receiver bandwidth is used to determine the noise power used into the calculation of signal-to-noise (S/N) ratio. This entry must be greater than 0 Hz and should be consistent with the type of communications activity being predicted. A typical value for single sideband (SSB) voice communication is 3000 Hz. For Morse code (CW) operation, a value of 500 Hz is typical. For AM, a value of 6000 Hz is adequate. A default value of 3000 Hz is selected if the <Enter> key is hit without a numeric value entered. For direct comparison with IONCAP S/N predictions, a normalized 1 Hz bandwidth can be used, since that is what IONCAP uses internally. 13. Required S/N Ratio The selection of a required Signal-to-Noise (S/N) ratio determines the threshold level of signal quality on which the propagation prediction is based. Typically, 10 dB or more S/N ratio is required for minimum voice communications capabilities in a 3 KHz (typical) bandwidth. In case of severe interference, or fading conditions due to multipath ionospheric effects, this value should be made higher. The required S/N ratio input by the operator is used to determine the %S availability of the link (i.e., S/N Availability). As the required minimum S/N value is raised, the RF link is less likely to support the requirement. Therefore, you should usually choose the absolute minimum S/N that is needed in order to assess the %S (S/N Availability percentage) and the %T (Total Reliability percentage) of the link. The %P (Path Availability percentage) of the link is independent of the minimum required S/N ratio, indicating instead that the path is open for some level of communication. 14. Transmitter Power The selection of transmitter power represents the amount of power (in kilowatts) delivered to the selected antenna. For example, to designate 100 watts delivered to the antenna, the entry would be made as 0.1 (i.e., 1/10 kilowatt). Transmitter power must be entered as a value greater than 0. Increasing or decreasing the amount of power has a direct bearing on the received S/N ratio and thus affects %N S/N Availability and %T Total Link Reliability. Thus, a 10 dB increase in signal power results in a 10 dB increase in received S/N ratio. The default selection value is 1 kW. [Note: Feedline and other losses to the antenna should be considered in the selection of transmitter power, since this value represents the amount of power actually delivered to a matched antenna.] 15. Sunspot Number (SSN) or Solar Flux Number (SFN) The level of solar activity influences ionospheric propagation. IONSOUND HDX TURBO accepts either SSN (Smoothed Sunspot Number) or SFN (Solar Flux Number) values. The program uses these values for computation of D, E, and F layer absorption effects on transmitted signals in the ionosphere. The SSN is based upon a statistically smoothed set of observations of sunspots and clusters of sunspots. The SSN can be obtained from publications such as QST (published by the ARRL) or from CQ Magazine. The SFN is based upon a 2800 MHz measurement of solar noise and is broadcast hourly on broadcast services such as WWV. Solar flux data is also available on most packet clusters. If real-time indications of solar activity are utilized, either SSN or SFN, running-averages should be kept and used as input to IONSOUND HDX TURBO. Robust predictions may involve 5, 10, 15 or 30 day running averages, while longer-term averages may be 6 months or longer. Prior to actual entry of SSN or SFN, a choice is presented for selection of using either SSN or SFN. To pick use of SSN an S should be entered; to pick use of SFN, an F should be entered. The default for this selection is use of the SSN. For SSN input, a value greater than 0 must be entered. For SFN input, a value greater than or equal to 63.75. If SSN is entered, IONSOUND HDX TURBO computes the equivalent SFN. Likewise, it computes and displays SSN if SFN is used. The default selection value for SSN is 0. [Note: Sunspot data can also be obtained from the "Solar Indices Bulletin", National Geophysical Data Center, Boulder, Colorado. See Appendix for a discussion of National Bureau of Standards (NBS) forecasts and prediction availability via radio broadcasts and on-line telephone/modem services.] [CAUTION: Following SSN/SFN entry, any manually entered changes to the F-layer height or the E-layer height should be carefully considered since program derived values will be overridden. In general, knowledge of vertical height from ionospheric soundings is useful and may be used if available.] 16. Minimum Elevation Angle The operator may enter a minimum elevation angle. This is useful if the horizon towards the desired target location is blocked by hills or other obstructions. Selecting a higher minimum angle precludes unrealistic low-order modes from being used in the computations. Following the elevation angle selection, the program computes the lowest-order F layer propagation mode (showing the number of hops), the calculated takeoff angle, and the unabsorbed isotropic receiver power density and field strength available at the distant receiver at the oblique critical frequency for this mode. Additional elevation angles may be tried if desired. With each minimum elevation angle the program finds the corresponding F layer hops, power density and field strength. Finally, after you have decided on a minimum elevation angle (or choose 0 degrees by default), the program will proceed. 17. Choosing Prediction Frequencies The menu for selection of prediction frequencies presents a variety of choices. In all cases, the entry of any frequency is a MHz value. Selection 1 allows entry of up to nine separate frequencies in the 1.8 MHz to 30 MHz range. The prediction order will be in the same sequence as the frequencies are entered. Selection 2 allows entry of a range of frequencies defined by the lowest frequency (greater than or equal to 1.8 MHz), a frequency increment (greater than 0), and a highest frequency (less than or equal to 30 MHz). A number must be entered for each prompt, or the program will simply cycle back to the first prompt. If the frequency increment chosen is too small, resulting in more than nine frequencies, the upper frequency limit will be truncated in order to limit the total number of frequencies to nine. If selection 2 is chosen and a previously defined range of frequencies already exists, the program will prompt the user whether to keep this previous range of frequencies by typing Y or N. The default for this choice is <Y> so that the program can continue with this previously defined range by simply hitting the <Enter> key. Selection 3 allows a predefined subset of all 9 HF amateur band frequencies (based on U.S.A. Allocations) currently available in the 1.8-30 MHz range. The frequencies are chosen such that there is one representative frequency from each band. [Note: Technically the 1.80 MHz frequency lies in the Medium Frequency (MF) band which is in the range 0.3 MHz to 3 MHz.] The All HF Amateur Band predefined frequencies are: 1.8, 3.5, 7.0, 10.1, 14.0, 18.1, 21.0, 24.9, 28.0 MHz. Selection 4 allows a predefined subset of 5 high-band HF amateur band frequencies (based on U.S.A. Allocations) currently available in the 14-30 MHz range. The frequencies are chosen such that there is one representative frequency from each band. The High-Band HF Amateur frequencies are: 14.0, 18.1, 21.0, 24.9, 28.0 MHz. Selection 5 will automatically load prestored frequencies from the file ION_FREQ.DAT. Up to nine frequencies, covering the range 1.8-30 MHz, can be prestored in the file. This file can be automatically modified by the user from within the program. It can be used to store frequency net lists or other favorite sets of frequency information. The default selection for the Frequency Menu is <3> which picks the 9 HF amateur band frequencies to be used for prediction purposes. The default selection is also obtained by hitting the <Enter> key. 18. Choosing Prediction Months The Month Selection Menu for selection of prediction months presents a variety of choices. If a selection entry between 1 and 12 is made, this entry will then represent a single prediction month. For example, an entry of 3 represents the month of March; 12 represents December. If selection 13 is made, all 12 months in sequence starting from January and ending with December will be used for prediction purposes. If selection 14 is made, the program will prompt you for the total number of months (between 1 and 12) for which you want predictions. Following the entry of the number of months, the program then prompts you for each month in the sequence which you care to use for prediction purposes. If selection 15 is made for entering an interval of months, the program will prompt you for the starting month, an integer increment value, and then the ending month. The program will then list the months corresponding to this selected interval and will ask you if you wish to change the range of months selected. If the month range interval is not acceptable to you, type Y to change the range. If the range is acceptable, then type N, the default, to proceed. Should the increment of months or range be inconsistent or inappropriate, the program will ask you to re-enter the month range. If selection 16 is made then the user has an opportunity to change the default month to be used in the selection process. When first executing, the default month is set to the present month. Select a new default month by entering a value from 1 to 12. The new default month will then be used for all subsequent propagation predictions. The setting of the default month does not preclude using any other month or months or month intervals when this menu is subsequently accessed. Selection 17 from the Month Selection Menu allows a return to the Main Menu of the IONSOUND HDX TURBO program. 19. Choosing Prediction Times The operator uses the Time Selection Menu to choose propagation prediction times. If 0 or <Enter> is selected, IONSOUND HDX TURBO computes a 24 Hour Summary Table for presentation to the computer screen. A maximum of 8 unique parameters may be chosen, in any order, for these predictions. Selections from 1 to 24 compute predictions for a single point in time. The hour and the minutes are entered in Universal Coordinated Time (UTC), using a number between 1.00 and 24.00. The digit (or digits) to the left of the decimal point correspond to the hour; the digits to the right of the decimal point correspond to the minutes (i.e., 12.35 corresponds to 12 hours and 35 minutes, UTC). Selection 25 chooses every full hour from 1 to 24 for the prediction process. Selection 26 allows entry of particular times of your own choosing. The user is prompted for the number of individual times, up to a maximum of 50. Each individual time is then entered one at a time following prompts. Selection 27 allows an interval of time values to be selected. The starting time is entered, then the time increment (which must be greater than 0), and finally the ending time. As a simplification, the time moment selected for the interval should be rounded to the nearest 15 minutes. If a very small time increment is selected such that the total number of individual times exceeds 50, a message will appear indicating that the total number of time moments has been truncated to 50. Following a continuation prompt indicating hit <Enter> to continue, the individual times in the overall time interval selected will appear on the screen. A prompt by the program will then ask whether you wish to change these times. If you want to change these times type Y; if these times are acceptable, type N. The default value for changing these times is <N> so that the program can continue by simply hitting the <Enter> key. [Note: If selection 27 is chosen by the user and a previously defined interval of time exists, the program will prompt whether you wish to use the previous time interval. The default for keeping the previously defined time interval is <Y> so that the program can continue by simply hitting the <Enter> key.] Selection 28 of the Time Selection Menu allows the user to return to the Main Menu. 20. Choosing Prediction Modes The Mode Selection Menu for choosing prediction modes presents a variety of choices, mainly for advanced users of IONSOUND HDX TURBO. These choice can greatly influence the propagation prediction process. At the beginning of the Mode Selection Menu, the lowest-order predicted F layer mode is displayed. Selecting a value of N from 1 to 10 causes the program to automatically seek other propagating modes supported by the ionosphere (for both the E layer and F layer) in addition to the value of the lowest order F layer mode. Selection of N = 1 (the default value) will cause the mode searching algorithm to consider at least 1 hop for the minimum number of F layer hops. Selecting N = 2 will cause mode searching to consider at least 2 hops. Likewise, further increasing the value of N selected will cause the algorithm to search out an ever-increasing complexity of E layer and F layer hop combinations, up to the maximum value of N = 10. As the value of selected N is increased, the prediction time will also increase accordingly. [Note: The mode searching algorithm is a complex process, since the program also considers mixed (i.e., combined E and F layer) modes of propagation. If at any time and at any frequency the lowest calculated F layer mode is blocked by the E layer, the program will seek mixed modes having the same number of hops, except that an E layer hop will replace one of the F layer hops. If this mode does not appear to propagate, another try is then made but with one more F layer hop than the original. If this mode in turn does not propagate, then a mixed mode at this increased number of hops is tried, except that one or two E layer hops are substituted in succession. The types of attempts at finding a propagating mode are continued in this fashion until all modes have been exhausted, up to and including two more hops than the starting number determined by the lowest F layer mode.] Selection 11 allows the user to enumerate which E layer, F layer or combined E and F layer hop modes the program should be forced to consider. Following this selection, the user is asked to input the number of modes to predict, up to a maximum of value of 10. Prompting for the desired number of modes takes place through individual entry of each separate E layer and F layer hop mode combination desired. To input a given mode, the value of the hop corresponding to the F layer mode is entered first, followed by a comma and then the value of the hop corresponding to the E layer mode. For example, to enter a mode corresponding to 3 hops using the F layer and 1 hop using the E layer a value of 3,1 is entered. Selection 12 allows the user to force the program to consider a single E layer propagation mode between the transmitter and the receiver. This one-hop E layer prediction can be useful when it becomes possible for E layer propagation to result in a higher MUF than the F layer mode. Selection 13 from the Mode Selection Menu allows the user to return to the Main Menu of the IONSOUND HDX TURBO program. 21. Printing Make sure that your printer is powered up and on-line before attempting to print anything. The most common usage of IONSOUND HDX TURBO is showing 24-hour prediction screens. These may be captured to the printer by the use of <Shift PrintScreen>. Two screens may be printed on a single sheet of paper. Most printers will require that you take them off-line and force a form feed in order to eject a printed page of paper. [Note: As an alternative to printing on paper, various file capture utilities may be utilized. An example of such a computer program utility is PRN2FILE.COM and its documentation PRN2FILE.DOC which is available from Ziff-Davis Publishing Co., 1 Park Avenue, New York, NY 10016. Download of PRN2FILE.COM from PC-Magnet, an online service of PC-Magazine is also available. Call 1-800-346-3247 for closest access point.] Bibliography Bandwidth and Signal-to-Noise Ratios in Complete Systems, CCIR Report 195, Vol. III, ITU, Geneva, 1963. Bixby C., and Morris, J., "The Art and Science of DXing," QST, Jan 1979, pp 11-14. CCIR 1986, "A Set of Simplified HF Antenna Patterns for Planning Purposes," Report 1062, International Telecommunications Union, Geneva. CCIR 1988, "Available Microcomputer-Based HF Radio Propagation Prediction Procedures," IWP 6/1 Doc 320, CCIR Secretariat, International Telecommunications Union, Geneva Davies K., "Ionospheric Radio," Blaisdell Publishing Co., Waltham, Massachusetts, 1969. Hall J., K1TD, "Propagation Predictions and Personal Computers," QST, Dec 1990, pp 58-59. Jacobs, G., Propagation: "Do-it-Yourself Forecasting," CQ, Oct 1990, pp 108-112. Johnson R.C., and Jasik, H., Antenna Engineering Handbook (2nd Ed.), McGraw-Hill Book Co., New York, 1984. Maslin N.M., "Assessment of HF Communications Reliability", AGARD Conference Proceedings No. 263: Special Topics in HF Propagation, AGARD-CP-263, 1979. Reference Data for Radio Engineers, Howard W. Sams, Inc., 1972. Schwartz M., Information Transmission, Modulation, and Noise, McGraw-Hill Book Co., New York, 1959 Solar Indices Bulletin, National Geophysical Data Center, Boulder, Colorado Sumner D., "Chart Your Way to Better DX," QST, Jan 1977, pp 58-60. The ARRL Antenna Book, 16th Edition, ARRL, Inc., 1988 The ARRL Operating Manual, ARRL, Inc., 1987. The ARRL Handbook, 1994, ARRL, Inc. Thrane E.V., "State of the Art of Modeling and Prediction in HF Propagation," AGARD Lecture Series No. 127: Modern HF Communications, AGARD-LS-127, 1983. White E., "Those Propagation Charts," How's DX:, QST, Apr 1983, pp 63-64. Glossary of Terms ARRL American Radio Relay League BBC British Broadcasting Corporation BRNG bearing CCIR International Radio Consultative Committee CW continuous wave, Morse code dB decibel dBuV dB signal level with respect to 1 microvolt DBUVM dB field strength with respect to 1 microvolt/meter (dBuV/m) dBW dB power with respect to 1 Watt dBWn dB noise power with respect to 1 Watt dBWs dB signal power with respect to 1 Watt DBWM dB power density with respect to 1 Watt/meter squared (dBW/m^2) DOS disk operating system ELE or ANG elevation or takeoff angle F/B front/back FOE E Layer critical vertical incidence frequency FOF F Layer critical vertical incidence frequency FOT optimum working frequency (usually below MUF) FREQ frequency Ham amateur radio operator HF high frequency HPF highest possible frequency Hz hertz (unit of frequency) IONCAP Ionospheric Communications Analysis and Prediction Program L PATH long path LUF lowest useful frequency (usually limited by absorption and noise) MCFO maximum critical oblique frequency MCFV maximum critical vertical frequency MHz megaHertz MUF maximum useable frequency (for a particular layer and distance) NOAA National Oceanographic and Atmospheric Administration (U.S.) NPW Noise Power in dB-Watts (decibels above or below 1 watt) NTIA National Telecommunications and Information Administration (U.S.) %SIG or %S signal-to-noise availability N, expressed in percent (%) [percentage of days of the month that the signal-to-noise ratio meets or exceeds the minimum signal-to-noise ratio] %PATH or %P propagation path availability P, expressed in percent (%) [percentage of days of the month that the predicted propagation path will be available] %TOT or %T total link reliability N x P, expressed in percent (%) [represents the numeric product of signal-to-noise availability, %SIG, and propagation path availability, %PATH, and signifies overall link quality] RX receiver S/N or SNR signal-to-noise ratio in decibels S PATH short path Glossary of Terms (continued) SBRNG switched bearing (long path bearing, 180 degrees opposite BRNG) SESC Space Environmental Services Center, NOAA, Boulder, CO (U.S.) SSN smoothed sunspot number SFN solar flux number (measured at 2800 MHz) SM+dB S Meter + dB [represents S0-S9 plus dB readings above S9] SVM signal voltage in dB-Microvolts (dBuV) SWL shortwave listener TX transmitter UTC Universal Coordinated Time VHF very high frequency WWV A radio station of the National Bureau of Standards (U.S.) Appendix NATIONAL BUREAU OF STANDARDS (NBS) SERVICES The U.S. National Bureau of Standards (NBS) broadcasts the latest geomagnetic Ap and K indices, the 2800 MHz solar flux level number (SFN), and short-term forecasts of expected propagation conditions on radio station WWV, simultaneously at 18 minutes past each hour on 2.5, 5, 10, 15, and 20 MHz. These transmissions originate from Ft. Collins, CO. In addition, radio station WWVH, located in Hawaii, broadcasts Geophysical Alerts at 45 minutes past the hour on 2.5, 5, 10 and 15 MHz. WWV and WWVH information is updated every 3 hours starting at 0000 UTC. The on-duty forecaster at the National Oceanographic and Atmospheric Administration (NOAA) Space Environmental Services Center (SESC) in Boulder, CO is also able to provide Alert data by calling 303-497-3171. This information is also available, free of charge, by calling NOAA's SESC at 303-497-3235. The SESC also provides a free on-line, menu-driven modem bulletin board service at 303-497-5000, 24 hours a day, for access to propagation data, solar reports, solar and geomagnetic data, and MUF predictions. Modem access is at 300, 1200, or 2400 baud, with a standard protocol of 8-bit data word, 1 stop bit, and no parity. NOAA publishes a booklet which should be considered required reading for those who would like to more completely understand and utilize WWV and WWVH propagation forecasts. It provides complete and easy-to-understand descriptions of the solar/terrestial indices, a glossary of terms, sources of information, and key details of NOAA's telephone bulletin board service (BBS). This booklet, "A User's Guide to the Space Environment Services Center Geophysical Alert Broadcasts," is available free of charge from the NOAA SESC by requesting a copy o NOAA Technical Memorandum ERL SEL-79. The address for obtaining this free booklet is: The Space Environment Services Center NOAA/ERL/SEL - R/E/SE2 325 Broadway Boulder, CO 80303-3328, USA