Nomad 2 as a Laptop-Free Field HQ

Why I built this

I wanted a throw-in-the-ruck box that could do three things without a laptop:

send/receive mesh messages, 2) drop GPS breadcrumbs, 3) do quick RF sanity checks.

Nomad 2 already has the radio, GPS, small screen, and keyboard, so I tried to make a boring, reliable setup I could bring up in under an hour.

• send/receive mesh messages, 2) drop GPS breadcrumbs, 3) do quick RF sanity checks.Nomad 2 already has the radio, GPS, small screen, and keyboard, so I tried to make a boring, reliable setup I could bring up in under an hour.

What this project is

A lightweight workflow on Nomad 2 (Pi 4 or Pi 5) that:

• boots cleanly,
• logs mesh packets automatically,
• shows GPS status and stores a simple breadcrumb file,
• (optional, Recon model) runs a quick SDR check.

It’s not about max range or fancy dashboards—just dependable basics I can repeat.

Build notes (the short version)

First boot

• Flash Raspberry Pi OS (64-bit), insert SD, attach LoRa whip + GPS puck.
• Join Wi-Fi/Ethernet, sudo raspi-config → enable SSH.

Mesh messages with the CLI

sudo apt update
sudo apt install -y python3-pip
pip3 install --upgrade meshtastic
meshtastic --info    # sanity check the onboard radio link

Auto-logging on boot

# /etc/systemd/system/meshlog.service
[Unit]
Description=Meshtastic packet logger
After=network-online.target
[Service]
Type=simple
ExecStart=/usr/bin/meshtastic --subscribe >> /home/pi/mesh.log 2>&1
Restart=always
User=pi
[Install]
WantedBy=multi-user.target
sudo systemctl enable --now meshlog
tail -f ~/mesh.log

GPS fix + breadcrumbs

sudo apt install -y gpsd gpsd-clients
sudo systemctl stop gpsd.socket gpsd
sudo gpsd -N -n /dev/ttyAMA0 -F /var/run/gpsd.sock   # adjust if needed
cgps -s

Tiny CSV logger I used:

python3 - << 'PY'
import time, json, subprocess, csv, os
p = os.path.expanduser('~/breadcrumbs.csv')
hdr = ['ts','lat','lon','alt','speed','track']
exists = os.path.exists(p)
with open(p,'a',newline='') as f:
    w = csv.writer(f); 
    if not exists: w.writerow(hdr)
    while True:
        try:
            out = subprocess.check_output(['gpspipe','-w','-n','10']).decode()
            j = json.loads(out)
            if j.get('class')=='TPV' and 'lat' in j and 'lon' in j:
                w.writerow([time.time(), j['lat'], j['lon'],
                            j.get('alt',''), j.get('speed',''), j.get('track','')])
                f.flush()
        except Exception: pass
        time.sleep(5)
PY

(Optional) SDR quick check on Recon

sudo apt update
sudo apt install -y rtl-sdr gqrx-sdr
rtl_test
gqrx

Small quality-of-life

• tmux for sticky session
• Crontab heartbeat every 2 minutes:

printf '#!/usr/bin/env bash\nmeshtastic --sendtext "HB $(date +%H:%M)"\n' > ~/hb.sh
chmod +x ~/hb.sh
(crontab -l; echo "*/2 * * * * $HOME/hb.sh") | crontab -

What happened in the field

• Rooftop vs backpack: On a low rooftop, messages landed more consistently than when the unit was buried in the pack. Antenna line-of-sight mattered more than I expected at short distances.
• Retries are fine: Short texts occasionally needed a retry in cluttered streets; the CLI made it trivial.
• GPS patience: Cold start took a bit; reacquisition was quick after that.
• Power reality: Screen brightness moves the needle. I kept it low and carried a small power bank for a top-off.
• Pi 4 vs Pi 5: For messaging + GPS + occasional scans, Pi 4 stayed cooler and felt “quiet.” If I were decoding heavier stuff, I’d pick Pi 5 and add more cooling.

Things that tripped me up

• Serial names: Double-check which /dev/tty* the radio/GPS use; a quick dmesg | grep -i tty saved time.
• SDR gain: Looks pretty until it clips—start conservative.
• Wi-Fi power save: If SSH feels flaky, check power management on the Wi-Fi adapter.
• Cable placement: Keeping the LoRa whip clear of metal helped consistency.

What I’d add next

• A single “kiosk” screen with last 10 messages, GPS status, and battery.
• Map tile cache + simple breadcrumb viewer for no-data areas.
• A “gateway” mode that buffers off-grid traffic and syncs over LTE only when available.

Minimal checklist (for future me)

Fresh OS, SSH on

• Fresh OS, SSH on
• pip3 install meshtastic → --info works
• gpsd up, cgps -s shows a fix
• (Recon) rtl_test OK, save a sane GQRX profile
• meshlog.service enabled and writing to ~/mesh.log

That’s it—simple, repeatable, and easy to pack