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MIC-E Enable
This setting enables the MIC-E format. If the MIC-E format is not selected, APRS text format will be used. This option
defaults to enabled.
MIC-E Force Printable
If this setting is selected, the MIC-E format data will be slightly modified to maintain printable characters. Sending non-
printable characters has been found to corrupt MIC-E data in some receivers in the past. When the data is modified,
some rounding will occur. For example, a bearing of 2 degrees will be converted to a bearing of 4 degrees.
MIC-E Message
This setting selects one of the 8 pre-assigned MIC-E messages. Caution should be used when selecting this setting, as
beaconing with the “Emergency!” setting will alert most APRS receiving users to your emergency.
MIC-E Path
This setting selects one of the 16 pre-assigned MIC-E paths. In order to use the digi path referenced above, this should
be set to “Conventional”.
Time Slotting
If enabled, the transmit offset setting sets the time from the start of the hour that a transmission will occur. After that
transmission, transmissions will continue at the Auto Transmit rate until re-syncing at the next start of the hour. This
option is useful to preset transmission times for multiple trackers. The Transmit Offset value must be less than the Auto
Transmit rate. TinyTrak3 will only synchronize with the GPS time at the start of the hour, so there may be a delay of up to
an hour before the TinyTrak3 begins transmitting in its assigned slot. TinyTrak3 will transmit at the Auto Transmit rate,
even if it has not yet synced. If the Auto Transmit rate evenly divides into 600 seconds, TinyTrak3 will synchronize at every
10 minutes. If the Auto Transmit rate evenly divides into 60 seconds, TinyTrak3 will synchronize at every minute. Time
slotting and SmartBeaconing are mutually exclusive. It is not important to sync every minute, because TinyTrak3 timing
doesn’t drift very much over an hour.
SmartBeaconing
These options setup SmartBeaconing. SmartBeaconing is an algorithm created by Steve Bragg for adjusting the transmit
rate by the speed and heading changes on the tracker. As the tracker moves faster, the transmit rate will increase linearly.
SmartBeaconing also uses CornerPegging to cause transmissions to occur when the tracker turns corners. In order to use
SmartBeaconing, the GPS must send speed and heading information with the GPRMC sentence. The SmartBeaconing
algorithm works like this:
IF (speed < slow_speed) // "Stop" threshold
beacon_rate = slow_rate;
ELSE { // We're moving; adjust beacon rate to speed, and peg corners
turn_threshold = min_turn turn_slope / speed; // adjust turn threshold according to speed
IF (heading_change_since_beacon > turn_threshold) AND (secs_since_beacon > min_turn_time)
CornerPeg = TRUE; // Corner pegging
IF (speed > fast_speed) // Adjust beacon rate according to speed
beacon_rate = fast_rate;
ELSE
beacon_rate = fast_rate * fast_speed / speed;
}
if ((secs_since_beacon > beacon_rate) OR CornerPeg)
// ... send beacon
More information on SmartBeaconing can be found at http://www.hamhud.net . SmartBeaconing and time slotting are
mutually exclusive: The Auto Transmit rate is ignored when SmartBeaconing is enabled.
SmartBeaconing Min Turn Angle, Turn Slope, and Min Turn Time
These settings set CornerPegging parameters for the minimum turn angle (degrees), turn slope (MPH-degrees), and
minimum turn time (seconds). Turns less than the minimum turn angle since the last transmission will not cause a
