Q: What is the data file structure used for TAP antenna libraries?
A: TAP uses dBase (.DBF) files for the antenna libraries.
Antenna Data Base Overview
The TAP antenna files are used by the TAP Antenna Lookup program to select a directional antenna and its associated horizontal and vertical patterns used by a TAP field strength calculation program. The major lobe gain of an antenna in a TAP antenna library may also be accessed from the antenna lookup program for the purpose of calculating transmitter power output (TPO) or effective radiated power (ERP) as the case may be. You can use the Antenna Files Editor to view, add to or modify antenna patterns in an antenna data baseAntenna_Data_Base_Summary or create and edit a new antenna library. Antenna files may also be imported from several manufacturers format using the "File | Import | To Antenna Data Base" menu.
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 TAP Antenna Files Editor to view, add to or modify antenna patterns in these files or create and edit a new set of antenna files.
The antenna file names follow a specific format:
Antenna Data Base File Names and Table Structures
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. All TAP manufacturers specs files have the following Microsoft FoxPro table structure:
|Field Name||Field Type||Field Width.Decimals||Field Description|
|GAIN||FLOAT||10.4||Major Lobe Gain|
|F_LOW||FLOAT||11.5||Freq Range: Low|
|F_HIGH||FLOAT||11.5||Freq Range: High|
The ATYPE_ID data value for each antenna record must be unique. TAP will expect the major lobe gain units (GAIN_UN) to be either "dBd", "dBi" or "REL" (relative field normalized for a maximum value of 1.0 in the major lobe).
Files such as AHDAND00.DBF that begin with the letters "AHD" contain the azimuth and gain values that define the horizontal antenna pattern for each antenna in the library. All TAP horizontal pattern files have the following Microsoft FoxPro table structure:
|Field Name||Field Type||Field Width.Decimals||Description|
The ATYPE_ID data value for each record in the set of records that defines one pattern must be identical to the ATYPE_ID of the associated AMS record for the particular antenna. The HOR_AZ values will typically start with 0 and should be in ascending order, representing conventional map azimuths (increasing in a clockwise direction). The HOR_FIELD data values in this file must have the same units (dBd, dBi, REL) as the major lobe gain units (GAIN_UN) stored in the AMS file.
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 ATYPE_ID data value for each record in the set of records that defines one pattern must be identical to the ATYPE_ID of the associated AMS record for the particular antenna. All TAP vertical pattern files have the following Microsoft FoxPro table structure:
|Field Name||Field Type||Field Width.Decimals||Description|
Vertical antenna gain values can be defined for angles (VER_ANGLE) from -90° (directly below the antenna) to +90° (directly above the antenna). The VER_FIELD data values in this file must have the same units (dBd, dBi, REL) as the major lobe gain units (GAIN_UN) stored in the AMS file.
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 TAP Antenna Files EditorAntenna_Files_Editor, you will notice an "INF" file such as AMSXXXXX.INF that was automatically generated for each of the three antenna tables referenced above. If you use Microsoft FoxPro to create your antenna data base as described below, you need not generate INF files for use in TAP.
Creating a TAP Antenna Data Base
Antenna Files Editor
When you run the TAP Antenna Files Editor Antenna_Files_Editor from the Editors options in the main menu, you will specify a new antenna manufacturers specifications file name in the Open File dialog box that first appears. As mentioned, this file name must begin with the letters "AMS". When you press OK the antenna editor that appears will create the specifications file along with any associated horizontal or elevation pattern files as needed.
Import TAP 3 Antennas
When you run the Import TAP 3 Antennas from the Editors options in the main menu, you will write antenna pattern information contained in the TAP 3 ASCII text file formats to an antenna data base for use with the current version of TAP. All antennas and their associated patterns converted in this manner are automatically written to an antenna data base consisting of files named "YYYXXXXX.DBF" where "YYY" refers to the three letter file type flag (i.e., "AMS") and "XXXXX" refers to the serial number of your TAP system.
Use this program to convert antennas created with earlier versions of TAP. In addition, TAP users have the option to create new antenna patterns outside of TAP with a text editor using the TAP 3 file format and then write this data to a TAP 4 data base. Consult your TAP 3 Technical Reference manual or call SoftWright for documentation of the TAP 3 horizontal and vertical pattern file formats.
TAP users have the option to create new antenna patterns outside of TAP using Microsoft FoxPro or other programs compatible with .DBF files. If you choose to create your data base files, you are advised to pay close attention to the table structures and file naming conventions documented in this topic in order for TAP to properly recognize and query data contained in your data base.
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