# Filter by Message Content

Incoming messages and the stations sending them can be filtered by the type of information in them. APRS defines various formatted elements that can be placed in the free-text comment field of a position report message, and YAAC recognizes them (if correctly formatted) and decodes them to provide additional information about the sending station or reported object (as appropriate). Such information includes:

- the coverage range of a station
- the Power, antenna Height, and Gain (PHG) of a station (used to infer the range)
- the frequency, subaudible tone, and repeater shift of a repeater object
- direction finding bearing
- course and speed of a moving station
- weather information from a weather station
- embedded base-91 telemetry data (rather than sending a separate telemetry message)
- National Weather Service multi-line outlines
- signpost labels
- digipeat aliases supported by a digipeating station
- any arbitrary text in the comment

The Msg Content filter can be used to isolate messages and/or stations sending those types of messages, or filter out stations sending those types of information.

If and only if the filter is enabled, only messages or stations either having the selected information (or not having it. depending on whether the "Accept only if doesn't contain specified items/text" checkbox is checked). For arbitrary text in the comment, specify the case-sensitive text in the text field. Note that incorrectly formatted information (such as PHG data put somewhere other than immediately after the position information) will not trigger by the checkboxes; conversely, correctly formatted data (such as PHG) will not show up in an arbitrary text search, because it will already have been extracted from the message's comment.