The filters are based on criteria you specify to determine the records from the Fixed Facility Database that you want to display. You can create and save as many filters as you like. When no filter is applied, all the records in the Fixed Facility Database are available. This function is especially helpful if you have a large number of records and you want to select a smaller subset to work with for a particular TAP session.

In addition to the Filter function, you can use the Find function to quickly locate a record by a word in the description or the record ID.

For example, suppose you want to see only records for facilities having a transmitter frequency between 150 and 160 MHz.

From the Fixed Facility Lookup form, click the Filter button:

In the pop-up menu that is displayed, select "New":

The Filter Setup form will be displayed:

This form allows you to select the field(s) in the Fixed Facility database you want to test, and the relationship and value you want to test for.

Use the Field to Match pulldown list to choose the first field you want to test. For this example, select the "TX Freq (MHz)" field.

(If you need to include a field in the filter that is not listed, please contact SoftWright. The Fixed Facility database contains over 200 fields. Only the most pertinent selection fields are listed, but additional options can be added.)

Use the Relation pulldown list to select the relationship you want to test. For this example, select the "greater than or equal to" (">=") item from the list.

Use the Value box to enter the value you want to test for. In this example, enter the value of 150:

Since this example includes two tests (greater than or equal to 150MHz AND less than or equal to 160 MHz) use the AND/OR pulldown list to select the Boolean relationship between the tests ("AND"):

When the AND/OR selection is not blank, a new line is displayed for the next part of the filter.

Use the same process to set the second part of this example filter:

Click the Continue button.

You will be prompted with the option to save the filter:

If you save the filter, you will be able to use it again later.

Click Yes to save the filter. A description of the filter is created automatically:

You can accept the description or enter a description that will be more helpful to you when you want to find the filter again later:

You should avoid using the equal sign "=" in the filter, since this will automatically be replaced with the abbreviation "EQ" to avoid confusion when the program reads the description.

After the filter has been saved, it will be applied to the Fixed Facility database display. Note the number of records and the current filter are displayed near the bottom of the form above the "Record Control" buttons.

If you want to display all the records in the Fixed Facility database click the Filter button and select "None (All Records)" to turn off the filtering function.

This will enable the program to display all records in the Fixed Facility database:

Note that the filter label has been removed, and the number of records shows the total number of records in the database.

If you have saved a filter and want to use that same filter again, click the Filter button and select the "Open" item.

A list of existing filters will be displayed, showing any previous filters you have created and saved:

Select the filter you want, and that filter will be applied to the Fixed Facility database display.

The Filter Setup form uses the field and relational values you specify to create the search criteria for the database. This information is used to construct the "WHERE" clause of the SQL Select statement.

If you are familiar with the rules of SQL syntax, you can manually edit a filter by checking the "Edit SQL Statement" box before clicking the Continue button:

If the "Edit SQL Statement" box is checked, the WHERE clause to be used in the SQL statement is displayed and can be edited.