Chapter 10
Beaconing
Fixed and SmartBeaconing position reports — exactly what is sent, and when.
A beacon is a position report: your callsign, position, symbol and comment. Other stations see it on their maps and APRS-IS sites such as aprs.fi. The app can beacon automatically, at a fixed interval or with SmartBeaconing, and on demand with the TX button.
#The beacon packet
CALL-SSID>APZGJJ,TCPIP*:=5309.27N/00100.73W-Comment Bat:85% /A=000150
CALL-SSID>APZGJJ,WIDE1-1,WIDE2-1:=5309.27N/00100.73W-Comment (RF copy)APZGJJis the app's destination (tocall), which identifies the software on aprs.fi and similar.=marks a position report from a messaging-capable station, so others know they can message you.- Latitude and longitude are uncompressed, rounded to a hundredth of a minute (about 18 m).
- The symbol table and code come from Settings. When you are stationary (under about 3 mph) the car symbol is sent as a house.
- The comment, plus
Bat:NN%and/A=NNNNNN(feet) if enabled, is limited to 43 characters. - On APRS-IS the path is
TCPIP*; on RF it is your RF path.
= (messaging capable) instead of !, and positions are rounded correctly — a value such as 59.996 minutes is now sent as the next whole degree rather than as 60.00 minutes.#Where beacons go
Every beacon is sent on every connected interface: APRS-IS if logged in, and each connected RF interface (KISS, Bluetooth, BLE, AGW, USB, Audio). Automatic beaconing only runs while at least one interface is connected.
#Position source
- QTH — the fixed position from Settings → FILTER is beaconed every interval seconds. SmartBeaconing does not apply.
- GPS — the current GPS fix is beaconed. If the fix is stale (older than twice the interval, minimum 60 s) or there is none, the QTH is beaconed instead once the interval has elapsed. A QTH of 0, 0 is never beaconed.
#Fixed interval
Set Fixed and an Interval in seconds. 0 disables automatic beacons. Please be considerate of the shared channel: 10 minutes (600 s) is plenty for a slow-moving station, 30 minutes (1800 s) for a fixed one.
#SmartBeaconing
SmartBeaconing beacons more often when you are travelling fast and when you turn, and rarely when you are stopped or moving slowly, giving a good track for the minimum of channel use. Choose Smart in Settings and GPS as the position source.
| Parameter | Value |
|---|---|
| Slow rate | Every 300 s (5 min) at 5 mph or less, including when stationary |
| Fast rate | Every 30 s at 60 mph or more |
| Between 5 and 60 mph | Interval falls linearly from 300 s to 30 s |
| Corner pegging | Extra beacon when the heading changes by 30° or more, moving at 3 mph or more, at least 10 s after the last beacon |
| Check rate | Every 10 s |
At 30 mph, for example, the interval is 300 − (25 ÷ 55 × 270) ≈ 177 s. The map toolbar shows your current speed while SmartBeaconing is active.
#Manual beacons
Press TX on the map toolbar to beacon immediately; the toast tells you whether GPS or QTH was used. The APRS Beacon Quick Settings tile and Beacon Now in Android Auto do the same from outside the app. Beacon on connect sends one beacon each time APRS-IS logs in.
After each beacon the home marker moves to the beaconed position, a magenta dot is added to your beacon trail, the widget is updated, and — for GPS beacons — a point is added to the track log if it is recording.