The first tab is the list of monitored stations. These are the other stations (identified by their
callsign-SSID values) whose telemetry data you want YAAC to watch, and what particular values of which
telemetry values you want to trigger an alarm. It is displayed as a two-level tree, where the first
level is the station identifiers, and the second level is the watched alarm values for each such
To monitor a station, type the station's callsign-SSID value into the "Callsign:" field, then click
the Add Callsign button. A node will be added to the tree with that callsign-SSID. Select the station
node with the mouse (it will be selected by default when newly added), add click the Add Analog Alarm
button to watch one of the 5 analog channels in a standard APRS telemetry message, or click the
Add Bit Alarm to watch one of the 8 binary bits at the end of the message.
For an analog input, select which of the 5 channels you want to monitor, what the value is
relative to the triggering threshold (<, > =, etc.), and the triggering threshold value itself.
There is also a checkbox to indicate whether to compare against the "raw" telemetry value (as seen in
the actual APRS telemetry packet), or the "cooked" value as transformed by a quadratic polynomial
whose coefficient values were sent in self-addressed APRS text messages whose body began with EQNS.
For a binary bit input, select which of the eight bits to test, whether the alarming condition is
bit set to 1 or to 0, and whether to use the "raw" value from the actual APRS telemetry message or
the possibly bit-flipped "cooked" value as specified by the XOR (exclusive-OR) bitmask from related
self-addressed APRS text messages beginning with BITS.
For both types of telemetry values, several choices are available for reporting the alarm, and
any combination of the choices can be used for each alarm trigger.
- An ALARM condition is sent to YAAC's event reporting subsystem. If the YAAC sounds plugin is
also installed, this is reported however the ALARM event type is configured to be reported, including
the option of having a custom text message (described below) sent to the text-to-speech synthesizer.
- The telemetry alarm window is moved in front of all other YAAC windows.
- A custom email is emailed to a specified recipient with a specified subject line.
- A custom text message is sent to a cellphone via a cellphone carrier's SMS or MMS text gateway.
For all of the reporting choices that refer to a custom message, the user can type in arbitrary
text. Macro buttons are provided to substitute the following real-time parameters into the text:
- FIELDVALUE - the "cooked" value of the field.
- THRESHOLD - the triggering threshold value as defined by the alarm trigger condition.
- TIMESTAMP - the date and time the triggering telemetry packet was received by YAAC, in the
the default format for the user's locale.
- FIELDNAME - the name of the telemetry packet field; if the sending station also sends self-addressed
APRS text messages beginning with PARM, the name specified for the alarming field in the most
recent PARM text message will be used, otherwise the label as would be reported by the
- SELFCALLSIGN - the callsign-SSID of the local YAAC station.
- CALLSIGN - the callsign-SSID of the station sending the telemetry.
- PROJECT - the telemetry project name as specified in self-addressed APRS text messages
beginning with BITS after the binary bit XOR mask; blank if BITS messages not sent.
- RAWFIELDNAME - the APRS protocol name of the telemetry field, in the format A1, A2, ... A5,
or D1, D2, ... D8.
- RAWFIELDVALUE - the actual numeric value specified in the APRS telemetry packet, regardless
of any EQNS text messages. Note this allows for values outside the APRS 1.0.2 protocol
specification's limit of integers 0 through 255; many newer stations are using wider
range values or floating point notation in the analog fields, and therefore may not be
sending EQNS text messages to rescale the values to display units.
Selecting a station or a field in a station and clicking the Delete button will remove the
alarm trigger condition from the YAAC system.