Distance and Bearing


Having the GPS data available suggested the utility of showing distance and bearing for selected stations. This is now available and is an expansion of the previous EME station list, now called a "QTH List."

Ctrl-U QTH List Dialog Box

First Dialog Box

Stations for the QTH List can be entered, edited or deleted using the QTH dialog box. Before this is opened, it is useful, but not required, to have a QTH number to get started. You can exit the "QTH Dialog Box" by hitting ENTER, then ENTER again for the second window. Nothing bad will happen and nothing will change.

Use ALT-U to view a list of locations and make note of the LOC number you wish to edit. Remember that "LOC 0" will be used as the default for calculating headings.  you can  enter something other than your own location here, if it makes sense.  It is more logical to use "LOC 0" as your own location.

To edit this LOC number, which might be for an empty line, open the Ctrl-U QTH Dialog Box, and enter the location number( 0-24 ). Select the button for either "Edit QTH"  or "Delete QTH" .  Select the format for the location data, either LAT/LON or 6 digit Grid, then hit "ENTER".

If the choice was "Delete QTH" then the screen will close, otherwise a new dialog box will open with the values for this QTH, if any, filled in. If the format selected was 6 digit grid, the grid locator will be displayed.


QTH Dialog Box



 While in this screen there is an option to save to the "In Dist/Bearing List". Checking this box will cause this QTH to be displayed in the "Distance and Bearing" list when the "Distance and Bearing" list is opened with ALT-U. If the box is checked and you do not want this QTH displayed in the B/D list, then "uncheck" the box. The next time Distance and Bearing is viewed, it will not be displayed..

Latitude can be entered as degrees only (DD.ddddd)on the first line, with the second line left as 0.0.  Degrees and minutes (DDMM.mm) can be entered with degrees(DD) on the first line and minutes (MM.mm) on the second line. For latitude, either a N, n, S, or s must be entered at the beginning or end of the degree value. Minus signs are not needed, and if entered, are ignored.

Longitude entry is identical in form to latitude, except that the indicators are E, e, W, or w.

ALT U
 
First Screen of distance and Bearing

Above is a "test" sample of the distance and bearing table. This results from the Alt-U (or u) command. The current QTH comes from the latest GPS data. If GPS is not being used, it is from the first location in the QTH list, called location 0. The list for this table is not the entire QTH list, but rather those selected from the second screen of the QTH Dialog Box . This allows EME locations to be omitted, if desired, or to have the list simplified by omitting unused stations. The maximum number of stations is 25, the first 10 of which are EME locations (0 to 9).

By default, the distances and bearings are between actual latitude and longitude coordinates. This can be changed to the centers of 6-digit grid squares by making the UHFA.CFG variable grid_ctr equal to 1. The bearings are clockwise from true north.

Hitting any key when the Distance and Bearing Table is viewed will bring up a second screen that is the raw data for the QTH list.

Alt-U Data Box

By default, the first 10 stations (0 to 9) of the QTH list are used for EME Doppler calculations. This number can be changed by the UHFA.CFG file variable n_eme_loc that can take any value between 1 and 25. Location 0 is always in the EME QTH list.

This shows the stations, descriptions and latitude/longitude. Empty entries are shown as blank lines. Entries with an asterisk as the first character of the description, will appear in the Distance and Bearing Table.

The format of latitude and longitude display is dependent on the configuration variable gps_ddmm. This determines if degrees or degrees and minutes are shown. See the details under Clock Configuration File Variables. Location number 0 does not show the number. This is a quirk of the printf function, but the missing zero is quite obvious.


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