TAP Antenna Data Base Overview

The TAP antenna data base refers to a set of Microsoft FoxPro version 2.5 tables found in the ANTENNAS\ sub-directory of your TAP program directory. This set of files will include as many as nine different files for each library of antennas depending upon the manner in which the library was created. All antenna files must be located in a sub-directory named \ANTENNAS under your TAP working directory. You can use the Antenna Files Editor to view, add to or modify antenna patterns in these files or create and edit a new set of antenna files.

Files such as AMSAND00.DBF that begin with the letters "AMS" contain manufacturing specifications such as an antenna description and a major lobe gain for each antenna in the library. Files such as AHDAND00.DBF that begin with the letters "AHD" contain the angle and gain values that define the azimuth antenna pattern for each antenna in the library. Files such as AVDAND00.DBF that begin with the letters "AVD" contain the angle and gain values that define the "elevation" or vertical antenna pattern. The AMSXXXXX.CDX, AHDXXXXX.CDX and AVDXXXXX.CDX files are the associated index files for the antenna data base. If you created a new antenna data base using the antenna editor, you may notice an "INF" file such as AMSXXXXX.INF that was automatically generated for each of the three antenna tables referenced above.

The data included in the antenna pattern files supplied with TAP contain manufacturing specifications supplied by antenna vendors, and SoftWright does not warrant the accuracy of the data nor the availability of antenna products.

1. This editor runs a number of error checking procedures as you enter new angles and field values into the azimuth and elevation parameters files of the antenna data base. Under certain circumstances, an inconsistency warning screen will appear when an inconsistency is detected between the major lobe and one or more field values displayed in the editor. From the Antenna Specifications tab folder, press the New button.
   
1. TAP will insert default values into the data fields. The white background of the text boxes is a reminder that you are in "edit" mode.
   
1. Replace the Antenna Type description with "Antenna Tutorial" as we have done below. In addition, set the Major Lobe Gain to 10.0 dBd. When you use TAP to create your antenna, you may wish to enter the input power and/or frequency range if you have these specifications available to you.
   
1. Press the Save button to record these changes in the antenna library.
   
1. Now press the Parameters Editor tab.
   
1. There are currently no field records specified. We will use a TAP sequential radial template to add a range of records to the grid. Press the Add Sequential Radials button.
   
1. The sequential radials lookup may or may not appear positioned to the "36 radials, 30 miles long" template, depending on the descriptions of the templates that exist in your data base. If necessary, use the VCR buttons at the bottom right side of this screen to navigate to this template. Pay no attention to the Terrain Extraction Specifications frame - the distance of these radials is irrelevant here. We are simply concerned with the Azimuth Specifications that define the range of angless that we will incorporate in the antenna editor.
   
1. When the 36 radials template is the current record, press Close.
   
1. TAP will automatically add 36 records to the grid and position the record pointer to the last record added. A default value of 1.0 dBd is specified for each field value. We will modify these gain values in this tutorial.
   
1. Let’s use the TAP sort mechanism to both sort on azimuth and move to the first angle. Press the Sort by Azimuth button.
   
   
1. Position your cursor in the field cell of azimuth (AZ_ANGLE) 000.00 as we have done.
   
1. Change the azimuth field value (AZ_FIELD) for azimuth 0 to 10.0 dBd.
   
1. In the same way, edit angless 10 to 120 as we have done below. In an effort to keep this tutorial as simple as possible, you will notice that we simply decrement each field value by one up to angle 180 where we will then increment the gains.
   
1. Use the vertical scroll bar to position angle 120 to the top of the grid making angles 130-240 accessible. Edit the field values as we have done.
   
1. Use the vertical scroll bar to position angle 240 to the top of the grid making angles 250-350 accessible. Edit the field values as we have done. This is enough editing for now!
   
1. Feel free to scroll through the grid to double-check your work. When you are ready, press the Plot Pattern button to look at what we have done.
   
1. When our pattern appears, you will notice the major lobe gain of 10 dBd on angle 0° just as we entered in the antenna files editor.
   
1. Feel free to experiment with the antenna plot options we demonstrated in previous sections of this tutorial. When you are ready to continue with this tutorial, press Close.
   
1. Let’s demonstrate one aspect of the error checking performed by TAP. We will enter an azimuth field value that exceeds the 10 dBd major lobe gain you specified in the Antenna Specifications tab. Position your cursor to the field value for angle 0° that is currently set to 10.0.
   
1. Change the AZ_FIELD to 11 as we have done.
   
1. Move to the Antenna Specifications tab.
   
1. The warning screen pictured below will appear. TAP has determined that field entered on angle 0° exceeds the major lobe gain we specified earlier. Is this now an 11 dBd antenna? If so, instruct TAP to Change major lobe gain to match maximum gain in file. Your other options include normalizing the gain values by reducing each gain, including angle 0° , by 1 dBd. In this scenario, angle 1° will be changed from 9 to 8, angle 2° from 8 to 7, and so on. The third option is to "bail out" and edit angle 0° again. Select the Change major lobe gain option and then press OK.
   
1. When the specifications appear, the major lobe gain is 11.0 dBd. Press Save to accept this change.
   
1. This concludes our tutorial. In practice, you will obtain the manufacturer’s specifications for your antenna and add realistic gain values for both the azimuth and elevation patterns. You will probably utilize more detail when you define you define these patterns. The majority of the antenna patterns supplied with the TAP program have at least 360 azimuth gains (0° to 359° ) and 181 elevation gains (-90° to 90° ). One final note. For convenience, we have added our tutorial antenna parameters to the Celwave antenna library. You may wish to remove this antenna and its parameters from the data base to avoid future confusion by pressing the Delete button.
   
1. Press Close to conclude this tutorial.