[ Meshtastic Cheat Sheet ]

One page, everything I reach for in the field. Print this page (it's laid out
to fit a single Letter sheet, black on white), or grab the PDF.
The why behind every line is in the full guide.

1. Flash: web flasher in a Chromium browser
   (Web Serial), pick your board, stable build
2. Connect: phone app (Bluetooth) or web client
3. LoRa > Region: US. A new node is UNSET and
   won't transmit until you pick one
4. Role: CLIENT (see below)
5. Give it a name you'll recognize
6. Preset: leave it on LongFast
No license needed: US 915 MHz ISM band.

Region   US here, and 915 MHz hardware to
         match; 868 and 915 can't hear each
         other
Preset   LongFast unless the whole mesh
         agreed to change it
Channel  same name and same key (PSK)
Get one wrong and you're on your own
private, silent network.

CLIENT       default, rebroadcasts. Almost
             every node should be this
CLIENT_MUTE  joins in, doesn't rebroadcast:
             a leaf sitting next to a router
ROUTER       real high sites only: roof,
             tower, peak. Never a mobile node
ROUTER_LATE  backup relay, rebroadcasts
             after the primary routers
REPEATER     relay only, no client UI
TRACKER      beacons its position, little else
Everything on ROUTER floods the airtime and
shrinks the mesh.

meshtastic --set lora.region US
meshtastic --set device.role CLIENT
meshtastic --set-owner "ridge-relay-01"
meshtastic --info     # dump the config

Up to 8 channels: 0 primary, 1-7 secondary.
The default LongFast key is public: anyone in
  range can read it, and so can MQTT.
Private group: new channel, random 256-bit
  key, share the QR code in person before
  you lose cell coverage.
DMs (firmware 2.5+) are encrypted to the
  recipient's key; channel posts aren't.
Encryption hides content, not that you sent,
  your position beacons or the metadata.

Never power it up without an antenna.
SMA and RP-SMA look alike and don't mate.
Use an antenna tuned for your band (915).
Height beats power. Keep coax short: thin
  RG174 eats dB fast at 900 MHz.
High gain = flatter pattern: great on flat
  ground, can overshoot a valley from a peak.

nRF52 board (RAK4631): sleeps at microamps
3000-3500 mAh 18650, a quality cell
5-6 W / 6 V panel + a real charge controller
Size the battery for the darkest week.
Check JST battery polarity before plugging.
IP65 box, vented, antenna on a bulkhead.

Same region, preset, channel and key on all
GPS locked before you leave (cold start can
  take minutes)
Everything charged, antennas on
Range-test a few hundred meters apart
Position: smart or every few minutes, not
  seconds. Lower the precision if it matters
Decide who carries the high relay

Region UNSET      set LoRa > Region
Wrong band        915 vs 868 hardware
Preset mismatch   everyone on LongFast
Channel or key    same name, same key
Antenna           loose, wrong band, or
                  SMA vs RP-SMA
Sited too low     get it up high
Nobody in range   test with a second node a
                  few meters away

US region + LongFast + the default channel
  and you're on the mesh.
Lines between islands on the map are MQTT
  (internet), not radio. Each island runs
  its own RF mesh: Oʻahu, Maui, Big Island.
Optional: a Wi-Fi node bridged to MQTT
  topic msh/US/HI puts you on the shared map.
In an outage the local RF mesh keeps going;
  the island-to-island links don't.