World of Ham Radio 1997

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U s e r ' s M a n u a l Y A G I - U D A D E S I G N P R O G R A M S (C) 1991-1994 Phadean Engineering Co., Inc. Post Office Box 611 Shrewsbury, MA 01545-8611 U.S.A. (508) 869-6077 All Rights Reserved Worldwide. Unauthorized Copying or Distribution of Software, Data Files, Text Files, Printed Material, or Other Material Copyrighted by Phadean is Strictly Prohibited Without Prior Written Authorization. INTRODUCTION Phadean's Yagi-Uda program disk contains the following executable programs: YAGI_UDA.EXE, NBS_YAGI.EXE, YAGIDATA.EXE, and XYPLOT6.EXE. Also on the disk are several video set-up files (CFG extension), sample output files (SMP extension), and ASCII text files (TXT extension). The EXEs will not run unless you follow the installation procedure described below. Please read this entire manual before using these programs. On Shareware disks, YAGI_UDA.EXE is replaced by YAGISHWR.EXE, and not all of the other programs will necessarily be included. YAGI_UDA computes the radiation pattern (elevation or azimuth) for the Yagi array defined in a user-specified input data file. When you enter the data file name, be sure to include the file extension (if any). NBS_YAGI computes the dimensions (element lengths, diameters, and spacings) for the six optimized Yagis described in the well-known NBS Tech Note 688. YAGIDATA is a program that creates a data file in the format required by YAGI_UDA. The input data file for YAGI_UDA can be created by YAGIDATA or by using a text editor. And files created by YAGIDATA can be edited to make changes. The programs prompt you for required input data, and out-of-range values will not be accepted. The diagram accompanying your program disk defines required input parameters. Refer to that diagram until you are familiar with each program's input. The required format for the YAGI_UDA input data file is as follows: LINE 1 - Frequency (Mhz), Soil Conductivity (mhos/m), Soil Dielectric Constant (dimensionless), Height Above Ground (meters), Total Number of Elements in Array LINE 2 - Spacing of each element (meters) measured from the Reflector, which must be at zero. The first entry on LINE 2 must be zero. LINE 3 - Element lengths (end-to-end, in meters), in order, from Reflector to last Director. LINE 4 - Element diameters (in centimeters), in order, from Reflector to last Director. Each entry must be separated from the others by either a comma or a blank (space). But each line must be terminated only by a carriage return (NO COMMA). The distribution diskette contains several sample files (*.SMP) that you can examine for the required input format. If you use YAGIDATA.EXE to create an input file, it will conform to the required format. YAGI_UDA always creates the same output data file, XYPLOT6.DAT, while the other two Yagi programs create output with a user-specified name. XYPLOT6.DAT is used as input by XYPLOT6.EXE to generate screen plots. Every execution of YAGI_UDA overwrites this data file. If you want to save the data in XYPLOT6.DAT, be sure to copy or rename it to some other filename. XYPLOT6.EXE uses a standard format ASCII data file whose format is described below. All run parameters for the Yagi antenna program are contained in XYPLOT6.DAT's header. By editing the data file, you can change the screen plot's appearance (titles, number of grid lines, and so on - see below). You can run XYPLOT6.EXE by itself to plot other data contained XYPLOT6.DAT, and you can create XYPLOT6.DAT to contain any data you wish. Just be sure to follow the prescribed format if you create your own version of XYPLOT6.DAT. Up to six curves can be plotted on the screen at one time. -2- INSTALLATION The Yagi-Uda programs are contained on one 5.25" 360 KB IBM-compatible floppy diskette. The programs may be executed from a hard disk or from the floppy. Installing the programs on a hard disk system, which is the preferred approach, is straightforward. Just copy the distribution diskette onto the hard disk. To use the Yagi programs, there is one file that you must create, and there are a few recommended procedures that you should follow. Before installing the Yagi programs, please read these instructions carefully. The few minutes you spend now will save time and frustration later. (a) Create the working directory where you want to install the vee programs using the DOS MD (make directory) command. The recommended directory is YAGI created using the command line MD \YAGI. (b) Copy all files from the Yagi program diskette into the working directory using the DOS COPY command. For example, the command line COPY A:\*.* \YAGI will copy all the required files. (c) You must select the type of graphics supported on your computer and create the file HDWRE.CFG by copying one of the graphics file from the following list into HDWRE.CFG: -3- PC Video Mode File to Copy into HDWRE.CFG Text mode VIDEO0.CFG 320x200 medium resolution CGA, 4 colors; text width 40. VIDEO1.CFG 640x200 high resolution CGA, 2 colors text width 80. 720x348 HGC monochrome graphics. VIDEO2.CFG 720x348 HGC monochrome graphics. VIDEO3.CFG 320x200 EGA medium resolution, 16 colors. VIDEO7.CFG 640x200 EGA high resolution, 16 colors. VIDEO8.CFG 640x350 EGA enhanced resolution with enhanced display (4 or 16 colors, depending on memory). VIDEO9.CFG 640x350 EGA high resolution using monochrome monitor. VIDEO10.CFG 640x480 VGA or MCGA high resolution, 80x30 text, monochrome mode. Use for black/white on IBM PS/2 systems. VIDEO11.CFG 640x480 VGA high resolution, 80x30 text, 16 colors. Use on IBM PS/2 models 50, 60 and 80. VIDEO12.CFG HGC - Hercules Graphics; CGA - Color Graphics Adapter; EGA - Enhanced Graphics Adapter; VGA - Video Graphics Array MCGA - Multicolor Graphics Array After selecting the appropriate VIDEO*.CFG file from the list, create the file HDWRE.CFG using the DOS COPY command; for example, COPY VIDEO3.CFG HDWRE.CFG sets up Hercules monochrome graphics. If you encounter a problem, it is almost certain that you selected the wrong video mode, in which case you should try copying another VIDEO*.CFG file into HDWRE.CFG. Whenever you change video modes, you must recreate HDWRE.CFG using this procedure. -4- Be sure that HDWRE.CFG is located in the same working directory as the Vee programs. The programs will not run unless HDWRE.CFG is contained in the working directory and is properly configured for your system. If your computer supports only monochrome text, the program YAGI_UDA will terminate execution with an error condition, but it will create the ASCII output file XYPLOT6.DAT that contains tabulated results. (d) Files on the Yagi distribution diskette are not write protected. If you delete one or more of them, accidentally or otherwise, then the file can be recovered only by using a file recovery program. However, there is no guaranty that you will succeed in recovering a deleted file; so be careful! It is advisable to write protect the executables (EXE extension) and HDWRE.CFG after installation. This prevents accidental deletion of an important file. You can do this by using the external DOS command ATTRIB to set the file attribute to +R. Do NOT write protect XYPLOT6.DAT! If you wish to execute the Yagi programs from a floppy diskette, be sure that the diskette contains HDWRE.CFG in the working directory. As a general rule, 50 to 75 KB of space is more than adequate to create the data file XYPLOT6.DAT; but, depending on the specific case, more space may be needed. If you encounter errors from from diskette, check all file sizes to be sure that enough storage is available. HINTS AND TIPS Input Data The Yagi programs prompt you for all required input data. If you enter an illegal value, for example, zero in a calculation that will be singular (divide by zero), the program flags the incorrect data by beeping and repeating the prompt. Just reenter correct data. If you are interested in values close to an illegal input, enter a slightly different number. For example, instead of entering "0", try something very small, such as "0.000001". Also, note that these programs use 299.8 megameters/sec as the velocity of light, which is more accurate than 300 megameters/sec which is commonly used. When several numbers are requested, each one should be separated by a space or a comma. Enter the entire sequence of requested data before pressing RETURN, which terminates data entry. -5- The Yagi_Uda dipole array consists of one reflector, one driven element, and directors. These elements are identified, respectively, as "REFL", "DE", and "D1", "D2", etc., in the Yagi schematic diagram accompanying your diskette. For each element, you must specify its end-to-end length (in meters), its diameter (in centimeters), and its distance from the reflector (in meters). The reflector is always at zero distance, and the program YAGIDATA will not allow you to enter any other value. This convention is important, and it must be followed. There are some other restrictions in YAGI_UDA as well. The frequency must be between 1.5 and 9999 Mhz. The earth dielectric constant must be less than 100. The antenna height must be between 1/8 and 5 wavelengths (unless free space). For antennas more than 5 wavelengths above ground, use the free space option (press RETURN instead of entering conductivity, dielectric constant, and height). The antenna elements must be between 1/8 and 7/8 wavelength total length. The smallest element diameter is the length divided by 10^8, and the largest is 1/4 of the length. These limits, by the way, are largely arbitrary and reflect the typical range of values. There's no fundamental limitation in YAGI_UDA that imposes these restrictions. If any user of this program requires out-of-range values, please contact Phadean directly (508/869-6077). The azimuth angle is measured counterclockwise on the earth's surface (viewed from above) from the Yagi's axis (boom). Zero azimuth is along the boom from the reflector toward the directors; +/- 90 deg are perpendicular to the boom off to the sides. The take-off angle is measured up from the earth's surface to the ray direction, which is specified using the two standard angles (take-off and azimuth). The antenna is parallel to the earth's surface. Azimuth angles greater (less) than +90 (-90) deg are not allowed, nor are take-off angles greater than 89 deg. The program YAGI_UDA allows you to specify any type of finite ("lossy") earth by inputting its conductivity (mhos/meter) and dielectric constant (dimensionless). Typical values are 0.001 mho/m and 4 for poor ground; 0.005- 0.01 mho/m and 8-12 for average ground; and 5 mhos/m and 81 for sea water. A perfect conductor has infinite conductivity and a dielectric constant of unity. The conductivity of copper is about 5.8x10^8 mhos/m. If you want to compute a free-space pattern, the ground can be made electrically "transparent" by setting the conductivity equal to zero and the dielectric constant to one. The antenna height in that case is irrelevant, but as a reminder of the "free space" condition, you might want to specify a large, eye-catching value (9999 meters, say). -6- One final word about using YAGI_UDA. The program looks for a file called "CHECKMOD.TXT", which must be in the default directory. Execution will terminate in an error condition if this file isn't present. CHECKMOD.TXT containsone of two keywords, either "OFF" or "ON", on the first line. These keywords turn module checking off and on, respectively, at run time. It's sometimes annoying to wait for the program to run through its self-diagnostic mode, and you can defeat it by turning the check function off. It's recommended, however, that every so often you run the check mode to be sure that no data on your disk has been corrupted. You can create and edit CHECKMOD.TXT with any text editor, or keep two copies around and rename the appropriate one as required. -7- Screen Plots The Yagi programs plot computed results directly on the screen, in addition to creating the output data file XYPLOT6.DAT. Immediate screen plotting allows you to quickly see how antenna performance varies as different parameters are changed and helps you develop insight into its behavior. Intelligent antenna design is as much art as engineering. A good designer develops intuition and judgement based on experience, which, in turn, give him a feel for how different parameters (element length, diameter, or spacing, for example) influence performance. XYPLOT6.DAT Required Format The first line of data in the file XYPLOT6.DAT must contain numerical setup parameters for the plotting routine. The sample file on the distribution diskette illustrates the format. Note that commas are used as delimiters on this line only. Commas on the other lines will result in run time errors, since they mark the end of a data block. The numbers on LINE 1 have the following significance (in order): Fraction of the screen used in the Y direction Fraction of the screen used in the X direction Number of vertical grid lines on the plot Number of horizontal grid lines on the plot Size of the X-axis label Size of the Y-axis label Number of decimal points for X-axis values Number of decimal points for Y-axis values Number of curves to be plotted (1-6) Size of the first line of the plot title Size of the second line of the plot title Size of the X-axis label Size of the Y-axis label "Any key..." message ON or OFF after plot is complete These parameters can only take on certain ranges of values. If XYPLOT6.EXE receives out-of-range data, it will be corrected. LINE 2 must contain the first line of the plot title. The second title line appears on LINE 3. These lines should be left blank if you not want titles. LINE 4 contains the X-axis label, and LINE 5 the Y-axis label. LINE 6 is reserved for comments, such as headings for the tabulated data. -8- Data are entered starting on LINE 7. The first column must contain the independent variable values, monotonically increasing from smallest to largest. In the columns that follow (1 through 6) are the pairwise data for each curve to be plotted. You must include a Y value for each X value for each curve. If you are plotting measured data for which you have only incomplete pairs of data, for example (X1,Y1), (X1,Y2),(X1,Y4) but not (X1,Y3) for four curves, you must insert some value for Y3. Otherwise, the input data will be read out of sequence and a run time error will occur. Plotting Curves You can plot screen plots on your printer using the SHIFT PrtSc keys. Before printing, you must load the DOS GRAPHICS.COM external command file to set up the screen for printing. Refer to your DOS Reference Manual for details on using GRAPHICS.COM. If you encounter difficulty in printing a plot, the problem is almost certainly an incorrect printer mode (in which case you should carefully set up the printer while referring to its User's Manual). An flexible alternative approach to generating plots is using a spreadsheet. YAGI_UDA always creates the same ASCII output file using a consistent format. Data is tabulated with run parameters in the header at the beginning of XYPLOT6.DAT. By using the "File-Import-Value" option available on most spreadsheets, you can read an entire Yagi_Uda data file, including header data, into numerical or ASCII values, as appropriate, in a spreadsheet. Yagi data can then be plotted in a variety of ways using the spreadsheet's plotting utilities. Users who don't have a spreadsheet program may wish to contact TRIUS, Inc., 231 Sutton Street, Suite 2D-3, P. O. Box 249, North Andover, MA 01845-0249 Voice (508) 794- 9377, FAX (508) 688-6312, BBS (508) 794-0762, 1200/2400,N,8,1. TRIUS supplies an inexpensive shareware spreadsheet with excellent capabilities (AS-EASY-AS). TRIUS also supplies a useful CAD program called DRAFT CHOICE. Please note that there is no relationship between Phadean and TRIUS and that this information is provided only for your convenience.