Ham Radio and Raspberry Pi: Practical Projects That Work

The Raspberry Pi is the Swiss army knife of ham radio computing. At $35-75 for the board, it runs Linux, handles audio processing, provides GPIO for hardware control, consumes minimal power, and runs silently. I've deployed six Pis for various ham radio tasks — some running for years without intervention.

Here are the projects that actually deliver value (not just blinky demos), how to implement them, and what to watch out for.

Project 1: Digital Mode Hotspot (Pi-Star / WPSD)

What It Does

Connects a DMR/D-Star/YSF/P25 handheld to internet-linked networks without a local repeater. Your handheld talks to the Pi via a low-power radio modem board. The Pi connects to reflectors/talk groups via internet.

Hardware

• Raspberry Pi Zero 2 W or Pi 3/4 ($15-75)
• MMDVM hat board ($30-60) — the radio modem
• MicroSD card (16GB+)
• Power supply (5V 2.5A)
• Small antenna (included with most MMDVM hats)
• Case (3D printed or purchased)

Software

• WPSD (formerly Pi-Star): Preconfigured image, web-based management, handles all the network connectivity.

Setup Summary

1. Flash WPSD image to SD card
2. Configure WiFi credentials in the boot partition
3. Boot Pi with MMDVM hat attached
4. Access web interface at the Pi's IP address
5. Configure your callsign, DMR ID, and desired talk groups
6. Key up your handheld — you're connected to the world

Tips

• Pi Zero 2 W is sufficient and smallest/cheapest option
• Use a static IP or reserve DHCP to always find the web interface
• WPSD handles updates automatically
• For best simplex range, an external antenna on the MMDVM hat helps

Value Rating: 9/10

If you use digital voice modes and don't have a local repeater, this is almost mandatory. Under $100 total and it gives you worldwide connectivity from a handheld.

Project 2: APRS iGate

What It Does

Receives APRS packets on 144.390 MHz (North America) and gates them to the internet APRS-IS network. Provides APRS coverage in areas without existing iGates. Can also beacon your home station position.

Hardware

• Raspberry Pi 3/4/5 ($35-75)
• RTL-SDR USB dongle ($25-35) for receive-only iGate
• OR: cheap Baofeng + audio cable for TX-capable iGate
• 2m antenna (even a mag-mount on a cookie sheet works)

Software

• Direwolf: Software TNC that decodes APRS from audio/SDR input and connects to APRS-IS
• rtl_fm: Pipes RTL-SDR audio to Direwolf

Setup (Receive-Only)

1. Install Direwolf on Raspbian
2. Configure rtl_fm to tune 144.390 MHz, pipe audio to Direwolf
3. Configure Direwolf with your callsign-SS (SSID), position, and APRS-IS credentials
4. Start the pipeline: rtl_fm → Direwolf → APRS-IS
5. Packets received on 144.390 appear on aprs.fi within seconds

Tips

• Set up as a systemd service for auto-start on boot
• Higher antenna = more coverage
• RTL-SDR Blog V4 has improved filtering that helps in strong-signal environments
• A receive-only iGate needs no additional license considerations beyond your Tech/General

Value Rating: 7/10

Useful if your area lacks APRS coverage. If you're already in a well-covered metro area, less impactful. Great community contribution in rural areas.

Project 3: WSJT-X / FT8 Monitoring Station

What It Does

Decodes FT8/FT4/WSPR 24/7 on one or more bands and uploads spots to PSKReporter. Passive propagation monitoring without tying up your transceiver.

Hardware

• Raspberry Pi 4 (minimum 2GB RAM) or Pi 5
• SDR receiver (RTL-SDR for budget, RSPdx for serious)
• HF antenna (any wire antenna works for receive)
• Audio interface (virtual — handled in software)

Software

• WSJT-X (runs on Raspberry Pi OS)
• PulseAudio or JACK for audio routing
• SDR software (CubicSDR, GQRX, or command-line rtl_fm/soapy) piping audio to WSJT-X

Setup

1. Install Raspberry Pi OS (desktop version for WSJT-X GUI)
2. Install WSJT-X from package or source
3. Configure audio routing from SDR to WSJT-X
4. Set WSJT-X to "monitor only" with your callsign and grid
5. Enable PSKReporter reporting
6. Leave running — it decodes and reports automatically

Tips

• Pi 4 with 4GB handles WSJT-X comfortably
• For headless operation after initial setup: use VNC to access the desktop remotely
• Multiple instances can run on one Pi (one per band) but CPU becomes the limit
• Consider JTDX as alternative (slightly different decoding algorithm)

Value Rating: 8/10

Excellent propagation awareness tool. Runs for months unattended once set up.

Project 4: Remote Station Control Server

What It Does

Put a Pi at your remote radio site (home, cabin, remote tower). Control the radio from anywhere via internet.

Hardware

• Raspberry Pi 4 or 5 (4GB minimum)
• USB audio interface (Signalink or similar)
• USB-to-serial for CAT control (if radio doesn't have native USB)
• Ethernet connection (wired preferred for reliability) or WiFi
• Power sequencing relay board (GPIO-controlled)

Software Options

• RemoteHams / RCForb client-server: Purpose-built remote control
• Mumble + hamlib + rigctld: Open-source stack for audio + radio control
• WebSDR + hamlib: Web-based receive with CAT control
• SDR++ + FlRig: Flexible combination

Setup Concept

1. Pi connects to radio via CAT (frequency/mode control) and audio (TX/RX audio)
2. Remote client connects to Pi via internet
3. Audio streams bidirectionally (low-latency codec)
4. CAT commands relay to radio
5. Pi handles PTT control via GPIO or CAT command
6. Optional: GPIO controls power sequencing, antenna switching

Tips

• Latency is critical for SSB: use Opus codec at lowest practical latency
• Secure the connection (SSH tunnel, VPN, or proper authentication)
• Plan for remote recovery: watchdog timer, remote power cycling, reliable boot
• UPS protects against brief power outages disrupting the Pi

Value Rating: 7/10

High value if you have a remote antenna site or want to operate from work/travel. Significant setup effort.

Project 5: WSPR Beacon Transmitter

What It Does

Transmits WSPR beacon signals on multiple HF bands using the Pi's GPIO pin as an RF output (with appropriate filtering).

Hardware

• Raspberry Pi 3/4/Zero 2
• Low-pass filter bank (critical — Pi's output is a square wave full of harmonics)
• GPS module for time reference (essential for WSPR timing)
• Optional: relay switching for multi-band filters

Software

• WsprryPi: Software that generates WSPR signals on the GPIO pin
• Uses the Pi's PLL/clock generator as an RF oscillator
• Power output: approximately 10-20mW (enough for WSPR worldwide)

Important Warnings

• FILTERING IS MANDATORY. The raw GPIO output is a square wave with strong harmonics at 3×, 5×, 7× the fundamental. Without proper LPF, you're transmitting illegal spurious emissions.
• GPS timing is critical — WSPR requires sub-second time accuracy
• Output power is fixed and low (~10-20mW). Adding an amplifier requires more filtering.
• This IS transmitting — you need an amateur license for the bands used.

Value Rating: 6/10

Neat project, but a dedicated WSPR transmitter kit (QRP Labs, Zachtek) does it better and safer. Best as a learning exercise about RF generation.

Project 6: Logging Server and Station Dashboard

What It Does

Runs a logging application accessible from any device on your network. Displays station status, propagation info, and recent QSOs on a dashboard.

Implementation

• CloudLog: Web-based amateur radio logging (PHP/MySQL)
• Install on Pi with Apache/Nginx + MariaDB
• Access from any browser on your network
• Integrates with QRZ, LoTW, eQSL for confirmation tracking
• Multiple operators can log simultaneously

Extras

• MagicDAB or similar for propagation dashboard
• Grafana for visualizing logging statistics
• Node-RED for station automation (turn on lights, power sequencing, alerts)

Tips

• Pi 4 with SSD (via USB) is much more reliable than SD card for database operations
• Daily backup of the database to a remote location
• Set up as a service that starts on boot

Value Rating: 7/10

Very useful for multi-device logging and household station sharing. CloudLog on a Pi is a robust setup.

General Pi Tips for Ham Radio

Reliability

• Use a quality SD card (Samsung, SanDisk industrial). Cheap cards die under constant writes.
• Better: Boot from USB SSD. Eliminates the #1 Pi failure mode (SD card death). A 128GB SSD is $15.
• Set up watchdog timer (hardware watchdog in Pi resets if system hangs).
• Read-only root filesystem for headless always-on systems (overlay filesystem).

Power

• Use official Pi power supplies or known-quality alternatives
• Undervoltage causes random crashes and SD card corruption
• Pi 4/5 need 5V/3A minimum under load with USB devices attached
• Consider powered USB hubs for multiple SDR/audio devices

RF Interference

• Pi boards emit some RFI from digital clocks. Keep them away from receive antennas.
• Shielding the Pi (metal case) helps significantly
• Ferrite chokes on USB cables reduce conducted noise
• HDMI cables are particularly noisy — disconnect if not using display

Headless Operation

• Configure SSH and VNC before deploying
• Set up auto-start services (systemd) for your ham applications
• Configure log rotation to prevent disk fill
• Set up email/Telegram alerts for service failures

The Raspberry Pi won't replace a proper shack computer for high-performance work, but for always-on, low-power, dedicated tasks — it's unbeatable. Six Pis running various ham radio tasks cost less than one Windows PC and consume under 25 watts total.