PacketMessage - Packet Radio Reborn

The Revival

In the 1980s and 90s, packet radio connected ham operators worldwide through a revolutionary digital network. BBSs, DX clusters, and real-time chat flourished over the airwaves.

Today, packet radio is more relevant than ever. In an age of fragile infrastructure and internet dependency, amateur radio offers something unique: truly decentralized communication.

We don't need high bandwidth for good-looking, efficient communication and entertainment. Most of the work happens on your device, with minimal network traffic required.

                            🌐
                            No internet needed
                        

                            ⚡
                            Works off-grid
                        

                            🆘
                            Emergency ready
                        

Features

📱

Software TNC

Use your phone as a TNC — just connect an audio cable to your radio. No extra hardware needed.

🔗

KISS TNC

Mobilinkd Bluetooth TNC support plus Direwolf network connectivity for desktop setups.

🛡️

Error Correction

FX.25 Reed-Solomon encoding with 16-byte error correction and bit-flip recovery.

📻

HF Ready

300 baud mode for HF bands — reach stations thousands of miles away.

📦

Payload Compression

Zlib compression shrinks your messages before transmission — send more data in fewer packets over the air.

💬

Modern Chat

Direct messages with delivery confirmation, group conversations, and global broadcast.

See It In Action

iPhone

PacketMessage main screen showing groups and direct messages — Groups and direct messaging

PacketMessage CQ global broadcast conversation — Global broadcast (CQ)

PacketMessage direct message with delivery confirmation — Delivery confirmation

PacketMessage settings showing TNC mode options — Multiple TNC modes

PacketMessage audio monitor showing channel activity — Channel monitoring

PacketMessage showing FX.25 error correction stats — FX.25 error correction

Android

PacketMessage Android EMCOMM group chat — EMCOMM group chat

PacketMessage Android direct chat with delivery confirmation — Delivery confirmation

macOS

PacketMessage macOS group chat with audio monitor — Group chat with audio monitor

PacketMessage macOS serial PTT settings for Digirig — Serial PTT for Digirig

How It Works

📱

Your Device

→

🔌

Audio Cable

→

📻

Your Radio

→

〰️

RF Waves

→

👥

Others

Three Ways to Connect

Software TNC

PacketMessage processes audio directly. Use a simple audio cable, or a Digirig for clean audio with automatic PTT control.

Bluetooth TNC

Use a Mobilinkd TNC3 or TNC4 for wireless connection to your radio. Clean audio, no cables to your device.

Network TNC

Connect to Direwolf or other KISS TCP servers on your network. Ideal for home station setups.

Technical Specifications

Protocol AX.25 v2.0 compliant

VHF/UHF Speed 1200 baud AFSK

HF Speed 300 baud FSK

Error Correction FX.25 Reed-Solomon (16 bytes)

Compression Zlib

Supports TNCs KISS protocol

Platforms iOS/iPadOS 17+, macOS 14+, Android 13+

Download Protocol Reference (PDF)

Suggested Frequencies

2m 145.070 MHz FM

80m 3.587 MHz USB

40m 7.065 MHz USB

30m 10.143 MHz USB

20m 14.093 MHz USB

VHF: 1200 baud AFSK FM · HF: 300 baud AFSK USB

Getting Started

What You Need

✓ iPhone, iPad, Mac, or Android device (iOS/iPadOS 17+, macOS 14+, Android 13+)
✓ A ham radio (VHF/UHF HT or mobile, or HF transceiver)
✓ Audio cable + Digirig (or vox cable) or Bluetooth TNC (Mobilinkd TNC3/TNC4) or Network TNC
✓ Valid amateur radio license

Example Setups

Baofeng UV-5R

iOS macOS

The most popular entry-level HT. Pair it with an inexpensive APRS K1 audio cable and you're on the air.

TNC mode: Software
PTT mode: None (VOX)
Cable: APRS K1 audio cable
Radio VOX: Set to level 1 (Menu → VOX → 1)

PTT via cable is unreliable on this radio. Use VOX mode instead — level 1 is the most sensitive setting, triggering transmission quickly when audio is present.

Yaesu VX-6R

iOS macOS

Compact HT with excellent audio. Works with DigiRig or Mobilinkd TNC.

Option A: DigiRig (Software TNC)

iOS

Cable: DigiRig VOX PTT cable + DigiRig Yaesu VX-6R cable set
TNC mode: Software
PTT mode: Multiplex
The cable handles PTT — no need to enable VOX on the radio
Adjust TX gain in Settings for reliable transmission

macOS

Cable: DigiRig Mobile USB + DigiRig Yaesu VX-6R cable set
TNC mode: Software
PTT mode: Serial (RTS)
Select the DigiRig serial port in Settings
Adjust TX gain in Settings for reliable transmission

Option B: Mobilinkd TNC

Cable: Mobilinkd cable for Yaesu 1-pin (CT-44 compatible)
TNC mode: Bluetooth
Scan and connect to your Mobilinkd in Settings
Enable VOX on the VX-6R, or configure Mobilinkd's built-in PTT if your cable supports it
Timing parameters are configured automatically on connect

Yaesu FT-710 / FT-991A

macOS only

HF/VHF/UHF desktop transceivers with built-in USB audio and serial. Connect directly to your Mac — no additional interface needed.

Connection: USB cable to Mac (radio appears as USB audio device + serial port)
TNC mode: Software
PTT mode: Yaesu CAT
Audio: Select the radio's USB audio in Settings → Audio Devices (input and output)
CAT: Select your radio model and serial port, match baud rate to radio's CAT settings (default 38400)

PacketMessage sends CAT commands (TX1;/TX0;) over the serial port to key and unkey the radio. The radio's USB audio carries the AFSK signal.

For detailed setup guides, troubleshooting, and advanced configurations, check out the in-app Info section.

Support PacketMessage

PacketMessage is built by a solo ham radio operator. Your donation helps fund continued development, hardware testing, and new features.

Thank you! Every contribution makes a difference.