ReticulumHF

Reticulum over HF radio using FreeDV.

Overview

Runs Reticulum over HF radio using FreeDV DATAC1 mode for modulation. Provides encrypted peer-to-peer communication without internet infrastructure.

Two installation methods:

• Pre-built Image - Flash and go. Includes web-based setup wizard and TCP bridge for Sideband.
• Manual Installation - Build everything yourself on existing Pi.

Pre-built Image

Download the SD card image, flash it, boot, configure via web portal.

Download

reticulumhf-20260109.img.xz (763MB)

Setup

1. Flash to SD card using Raspberry Pi Imager - select "Use custom"
2. Insert SD card, connect radio via Digirig, power on
3. Connect phone to WiFi: ReticulumHF-Setup (password: reticulumhf)
4. Open http://192.168.4.1 in browser
5. Complete setup wizard - select radio model, verify audio levels
6. In Sideband, add TCP interface: 192.168.4.1:4242

What's Included

• Raspberry Pi OS Bookworm Lite (64-bit)
• RNS with TCP server on port 4242
• freedvtnc2 (FreeDV DATAC1 modem)
• codec2 (built from source)
• i2pd (I2P transport)
• Hamlib rigctld
• Web portal with service controls

Network

WiFi SSID	ReticulumHF-Setup
WiFi Password	reticulumhf
Gateway IP	192.168.4.1
RNS TCP	4242
SSH	pi / reticulumhf

Sideband Configuration

Setting	Value
Host	192.168.4.1
Port	4242
Interface Type	TCP Client

Audio Tuning

ssh pi@192.168.4.1
alsamixer

• Press F6 to select USB audio device
• Press F4 for capture view
• Set capture 70-80%, playback 40-60%
• Save: sudo alsactl store

---

Manual Installation

Build everything from scratch on a fresh Raspberry Pi OS installation.

Test Results

Tested with two identical setups. Local test only (73 miles). Last test was in December of 2025.

Test Environment

Component	Specification
Computer	Raspberry Pi 4 (4GB)
OS	Raspberry Pi OS Lite Bookworm 64-bit
Radio	Xiegu G90 (Hamlib model 3088)
Interface	Digirig Mobile (USB audio + CAT)
Reticulum	0.8.4
freedvtnc2	Latest from PyPI
codec2	Built from source

Performance Specifications

From codec2 documentation (https://github.com/drowe67/codec2/blob/main/README_data.md):

Parameter	Value
Data rate	980 bps
RF Bandwidth	1.7 kHz
Payload per frame	510 bytes
Frame duration	4.18 seconds
Target SNR	5 dB
Carriers	27

Range depends on HF propagation (ionosphere, solar activity, time of day).

Architecture

+-------------+      +----------+      +-----------+
|  NomadNet   |----->|Reticulum |----->|freedvtnc2 |
|   (LXMF)    |      |  Stack   |      |   (TNC)   |
+-------------+      +----------+      +-----------+
                                             |
                                             v
                                       +---------+
                                       | rigctld |
                                       |  (PTT)  |
                                       +---------+
                                             |
                                             v
                                       +---------+
                                       |Digirig  |
                                       | Audio+  |
                                       |  CAT    |
                                       +---------+
                                             |
                                             v
                                       +---------+
                                       | G90 HF  |
                                       |  Radio  |
                                       +---------+

Work Flow:

1. User writes message in NomadNet
2. Reticulum encrypts packet with recipient's public key
3. freedvtnc2 modulates to FreeDV DATAC1 audio
4. rigctld keys radio, audio transmits over HF
5. Remote station decodes and delivers to NomadNet

Step 1: System Preparation

Flash Raspberry Pi OS Lite (Bookworm, 64-bit). Enable SSH.

ssh user@<pi-ip-address>
sudo apt update && sudo apt upgrade -y

Step 2: Install Dependencies

sudo apt install -y git build-essential cmake python3 python3-pip python3-venv \
    portaudio19-dev alsa-utils libhamlib-utils libhamlib-dev pipx
pipx ensurepath
source ~/.bashrc

Step 3: Build Codec2

cd ~
git clone https://github.com/drowe67/codec2.git
cd codec2
mkdir build_linux && cd build_linux
cmake ..
make
sudo make install
sudo ldconfig

Verify:

ldconfig -p | grep codec2

Step 4: Install Reticulum Stack

pipx install rns
pipx install nomadnet
pipx install freedvtnc2
pipx runpip rns install numpy pyaudio scipy
pipx runpip nomadnet install numpy pyaudio scipy

Initialize Reticulum config:

rnsd --config ~/.reticulum &
sleep 3
pkill rnsd

Step 5: Connect Hardware

1. Connect Digirig to Pi via USB
2. Connect Digirig audio cable to G90 ACC port
3. Connect Digirig CAT cable to G90 CAT port
4. Power on G90

Step 6: Verify Hardware

# Check USB devices
lsusb
# Expected: Silicon Labs CP210x (CAT) and C-Media CM108 (audio)

# Check audio
arecord -l
# Expected: USB PnP Sound Device

# Check serial
ls -la /dev/ttyUSB*
# Expected: /dev/ttyUSB0

# Add user to dialout group
sudo usermod -a -G dialout $USER
# Log out and back in

Step 7: Test Radio CAT

rigctl -m 3088 -r /dev/ttyUSB0 -s 19200 f

Expected: Returns current frequency (e.g., 7100000).

Step 8: Configure G90 Audio Input

On the G90:

1. Press FUNC
2. Press POW until you see "INPUT"
3. Use knob to select LINE (not MIC)

Set ALSA levels (adjust card number as needed):

amixer -c 3 sset 'Speaker' 64%
amixer -c 3 sset 'Mic',0 cap 75%
amixer -c 3 sset 'Mic' unmute
sudo alsactl store

Step 9: Configure Reticulum

Edit ~/.reticulum/config:

[reticulum]
  enable_transport = no

[interfaces]
  [[Default Interface]]
    type = AutoInterface
    enabled = yes

  [[FreeDV HF]]
    type = TCPClientInterface
    enabled = yes
    target_host = 127.0.0.1
    target_port = 8001
    kiss_framing = yes

Step 10: Start the Stack

Terminal 1 - Start rigctld and freedvtnc2:

rigctld -m 3088 -r /dev/ttyUSB0 -s 19200 \
    --set-conf=serial_handshake=None,rts_state=OFF,dtr_state=OFF &

freedvtnc2 --input-device 1 --output-device 1 --mode DATAC1 \
    --rigctld-port 4532 --ptt-on-delay-ms 300 --ptt-off-delay-ms 200 \
    --output-volume -3

Terminal 2 - Start NomadNet:

nomadnet

Step 11: Test Transmission

In NomadNet:

1. Select Network tab
2. Send an announcement

Radio should key up for 3-5 seconds and transmit.

---

Optional: I2P Bridge

For base stations bridging HF to internet:

sudo apt install -y apt-transport-https curl
curl -o i2p-archive-keyring.gpg https://geti2p.net/_static/i2p-archive-keyring.gpg
sudo cp i2p-archive-keyring.gpg /usr/share/keyrings/
echo "deb [signed-by=/usr/share/keyrings/i2p-archive-keyring.gpg] https://deb.i2p.net/ bookworm main" \
    | sudo tee /etc/apt/sources.list.d/i2p.list
sudo apt update
sudo apt install -y i2p i2p-keyring
sudo systemctl enable i2p
sudo systemctl start i2p

Add to ~/.reticulum/config:

  [[I2P Interface]]
    type = I2PInterface
    enabled = yes
    connectable = yes
    peers = kfamlmwnlw3acqfxip4x6kt53i2tr4ksp5h4qxwvxhoq7mchpolq.b32.i2p

Troubleshooting

Hardware Verification

lsusb                      # List USB devices
arecord -l                 # List audio devices
ls -la /dev/ttyUSB*        # List serial ports

CAT/PTT Test

rigctl -m 3088 -r /dev/ttyUSB0 -s 19200 T 1  # Key transmitter
rigctl -m 3088 -r /dev/ttyUSB0 -s 19200 T 0  # Unkey transmitter

Reticulum Status

rnstatus                        # Interface status
tail -f ~/.reticulum/logfile    # Live log

Common Issues

No /dev/ttyUSB0:

• Check USB cable connection
• Verify Digirig is powered (LED lit)
• Run dmesg | tail after plugging in

CAT command fails:

• Verify baud rate matches radio (G90 uses 19200)
• Check user is in dialout group
• Try rigctl -m 3088 -r /dev/ttyUSB0 -s 19200 f

No audio device:

• Run arecord -l to find device number
• Adjust --input-device and --output-device in freedvtnc2 command

Radio not keying:

• Test PTT manually: rigctl -m 3088 -r /dev/ttyUSB0 -s 19200 T 1
• Check G90 is in correct mode (USB-D for data)
• Verify rigctld is running on port 4532

WiFi AP not visible (pre-built image):

• Wait 60 seconds after power on
• Check Pi LEDs (solid green = booted)
• Power cycle Pi

Sideband won't connect (pre-built image):

• Verify connected to ReticulumHF-Setup WiFi
• Check rnsd running: ssh pi@192.168.4.1 "systemctl status reticulumhf-rnsd"
• Verify port 4242: ssh pi@192.168.4.1 "ss -tlnp | grep 4242"

Verified Hardware

Component	Model
Computer	Raspberry Pi 4 (4GB)
Radio	Xiegu G90 (Hamlib 3088)
Interface	Digirig Mobile
Phone App	Sideband (Android)

References

Software:

• Reticulum Manual: https://markqvist.github.io/Reticulum/manual/
• codec2 Data Modes: https://github.com/drowe67/codec2/blob/main/README_data.md
• freedvtnc2: https://github.com/xssfox/freedvtnc2
• Sideband: https://github.com/markqvist/Sideband
• Hamlib Supported Radios: https://github.com/Hamlib/Hamlib/wiki/Supported-Radios

Propagation:

• prop.kc2g.com: https://prop.kc2g.com/ - Real-time MUF/foF2 maps
• VOACAP Online: https://www.voacap.com/hf/ - HF propagation prediction
• HamQSL Solar Data: https://www.hamqsl.com/solar.html - Current solar indices

License

MIT License - See LICENSE file

Author

Light Fighter Manifesto L.L.C. https://lightfightermanifesto.org