APRS is a world wide network. The world wide data volume is immense, too much for a small Smartphone. Therefore it is a must to filter the data stream and receive data of interest only.
* max. distance to the own station
* Callsigns or part of callsigns (i.e. prefixes), the Friends Filter
* Weather Stations
* other APRStrack User
Choose the filter type and enter the range of interest.
Range to own station and range to friends:
all stations within this range around the own station (or the friends stations) are recorded. The position of the own or friends station must be known by APRS.
Weather Stations range:
all wx stations within this range around the own station are recorded.
shows all other APRStrack user (if online).
usually the filter commands are build by APRStrack. You can see the raw filter in the display. Experts may enter their own filter in raw data format which allows to use all filters offered by the APRS-IS servers.
Friends (Callsign 1-9):
Up to 9 callsigns can be filtered for recording. This is
usually used for friends but can also be used to record
complete areas or countries using the wildcard '*'.
Example: if ON* is entered than all stations from Belgium
will be recorded.
Attention ! if this filter is very short like K* then all stations beginning with 'K' will be received which is a huge amount of data overloading your phone or tablet. Its better to use a more specific filter.