== Computing Each QSO's Distance and Azimuth ==

In order to compute the distance and azimuth your signals traveled in a QSO, DXKeeper needs three items of information:

 1. your location

 1. your QSO partner's location

 1. an indication of whether your signals took the short path or the long path to your QSO partner


=== Your Location ===

If a QSO specifies a [[http://www.dxlabsuite.com/dxkeeper/Help/MultipleQTHs.htm|my QTH ID]] for a '''my QTH''' that specifies a valid latitude and longitude, then this latitude and longitude is used as "your location". Otherwise, DXKeeper uses the '''QTH Latitude''' and '''QTH Longitude''' specified on the '''Configuration''' window's '''Defaults''' tab.

=== Your QSO Partner's Location ===

DXKeeper can record your QSO partner's grid square and a latitude and longitude with each QSO. If you record a grid square, DXKeeper automatically computes and records the latitude and longitude, and vice versa. While the grid square displayed by [[DxInfo|DXView]] after it performs a callsign or prefix lookup is accurate enough for aiming an antenna, it is not accurate enough for distance calculations or for award tracking -- and so is not automatically recorded by DXKeeper. A grid square returned by a [[CallbookLookup| callbook lookup]], manually typed into the '''Capture''' window or '''Main''' window's '''Log QSOs''' tab (from information received over the air), or [[QSOImport| imported]] from a record in an ADIF file is considered sufficiently accurate for this purpose and will populate the QSO's Grid, Latitude, and Longitude items.

=== Azimuth and Antenna Path ===

If you are using DXView to [[http://www.dxlabsuite.com/dxview/Help/Operation.htm#Positioning%20an%20antenna%20rotator|control a rotatable antenna]], DXKeeper will automatically record the last antenna azimuth sent to the rotator, as well as whether the antenna was rotated to a short path or long path heading. If you aren't using DXView to to rotate your antenna, you can enable DXView's [[https://www.dxlabsuite.com/dxview/Help/Configuration.htm#Rotor%20Control%20tab|Report computed short path heading when disabled or on unsupported band]] option, and set the default '''Antenna Path''' selector to '''S''' on the [[https://www.dxlabsuite.com/dxkeeper/Help/Configuration.htm#Defaults%20tab|Defaults tab]] of DXKeeper's Configuration window.

you can manually record the antenna path via DXKeeper's '''Capture''' window or its '''Main''' window's '''Log QSOs''' tab; you can also manually record the antenna azimuth, but that's not required for a distance calculation (because if the path is not ''short'' or ''long'', there's no way to accurately compute the distance short of measuring the transit times with a high-precision clock). You can also set a default antenna path of the '''Defaults''' tab of DXKeeper's '''Configuration''' window.

=== Updating Already Logged QSOs ===

If you have been logging QSOs without recording their antenna path, you can use DXKeeper's '''Advanced Sorts, Filters, and Modifiers''' window's [[QSOModifying| Modify QSOs]] panel to set the the antenna path items of your QSOs to ''S'' en masse; just be sure to make a log backup beforehand by clicking the '''Backup''' button on the '''Configuration''' window's '''Log''' tab. After manually correcting the antenna path items of any known long path QSOs to ''L'', you can then use the [[QSOModifying| Modify QSOs]] panel to 

 1. compute the distance item for each QSO by setting the '''Item ADIF field name''' selector to ''DISTANCE'' and by setting the '''Item new value''' to ''<COMPUTE>'' before clicking the '''Mod''' button

 1. compute the antenna azimuth item for each QSO by setting the '''Item ADIF field name''' selector to ''ANT_AZ'' and by setting the '''Item new value''' to ''<COMPUTE>'' before clicking the '''Mod''' button


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