Chapter 1
Introduction
An APRS station in your pocket — internet, RF and car in one app.
G7JJF APRS Client is a full-featured Automatic Packet Reporting System (APRS) station for Android phones and tablets. It is written for licensed radio amateurs who want a single app that can sit on the internet APRS network (APRS-IS), talk to real radios through a range of TNCs, and still be comfortable to use on a phone screen or in the car through Android Auto.
Everything the app hears — whether it arrives from an APRS-IS server, a Bluetooth TNC in your pocket, Direwolf on a Raspberry Pi in the shack, or the phone's own microphone — is merged into one packet stream. The map, the station log, the message threads and the alerts all work from that single stream, so it does not matter how a station was heard: you see it in the same place and can reply to it in the same way.
#What the app can do
- APRS-IS client with server-side range, prefix, buddy and custom filters, automatic passcode calculation, keepalives and automatic reconnection.
- Six RF interfaces that can all run at once: TCP KISS (Direwolf, hardware TNCs on the LAN), Bluetooth Classic SPP in KISS or text mode, Bluetooth Low Energy (Nordic UART, Mobilinkd BLE KISS or HM-10 serial), AGWPE/Direwolf AGW port, USB serial (KV4P HT, CP2102-based TNCs) and a built-in Bell 202 audio soft-TNC that uses the phone's microphone and speaker.
- Live map with four base layers (CARTO, OpenStreetMap, satellite, topographic), emoji or official APRS symbols, clustering, trails, age fading, distance rings, measuring, waypoints, KML overlays, address search and offline tile download.
- Full APRS decoding — uncompressed and compressed positions, Mic-E, DAO extra precision, weather (positionless and with position), objects and items (including kills), telemetry with PARM/UNIT/EQNS definitions and comment telemetry, status, messages, bulletins and NWS alerts.
- Messaging in conversation threads with message numbers, acks, rejects, APRS 1.1 reply-acks, automatic retries, duplicate suppression, templates, a route override (force APRS-IS or force RF) and inline reply from the notification.
- Beaconing at a fixed interval or with SmartBeaconing (speed-dependent rate plus corner pegging), from GPS or a fixed QTH, with optional altitude and battery level.
- RX iGate (RF to APRS-IS) and TX iGate (APRS-IS to RF, messages for local stations and optionally positions of watch-listed stations) using correct q-constructs and third-party format, a fill-in digipeater, and Beacon Check to see which digipeaters and iGates carried each of your RF beacons.
- AX.25 connected-mode packet terminal for BBSs and nodes (BPQ, FBB and similar), implementing T1/T3/N2 timers, polls and finals, REJ recovery and window control as described in the AX.25 specification, connecting via digipeaters, with macros, session logs and a monitor that decodes NET/ROM.
- Objects manager, APRS services helper (ANSRVR, WHO-IS, EMAIL-2, SMSGTE, WXBOT, APRS OTA, APSPOT, APRS2SOTA, MPAD, QRX, Telegram and WhatsApp gateways, WLNK-1 and more), email forwarding of incoming messages, DX cluster, ISS pass prediction with pass reminders, solar propagation, sunrise/sunset, grid square and passcode tools, and a barometer using the phone's pressure sensor.
- Logging — track log with GPX export, QSO log with ADIF export, raw stream recording, packet rate graph, TX history, station export to CSV or KML.
- Alerts — watch list, circular geo-fences, proximity to your position, weather thresholds, bulletin keywords and message notifications, optionally spoken aloud.
- Android Auto with a home grid, station/weather/repeater/object lists, messages with reply, and a live drawn map on head units that support it.
- Home-screen widget and Quick Settings tiles for connect and beacon.
- Station profiles, settings export/import and full backup and restore.
#About this manual
This manual describes version 1.9.9 (build 55). Every chapter is written from the behaviour of the app itself: where the manual gives a number — a timer, a limit, a default — it is the value the app actually uses. Button and menu names are given as they appear on screen. Many on-screen labels carry a small emoji icon; the manual leaves the icon out and gives only the words (for example the menu item shown as a satellite dish and the words AX.25 Packet Terminal is written simply as AX.25 Packet Terminal).
Paths through the menus are written with arrows, for example Menu → Radio Tools → ISS Passes. Menu always means the main menu opened with the ☰ button at the top left (or the Tools tab).