PassageMail™
Everything you need to get the most out of PassageMail Weather at sea.
PassageMail connects to your GO! in two steps so you can log in indoors and connect when ready:
Signal bars update dynamically — every 10 seconds when searching for satellites, every 30 seconds when signal is healthy. The GO! Monitor shows real-time signal transitions during sync so you can see satellite passes as they happen.
View and change your GO! WiFi settings directly from the app: SSID, password (WPA2), and channel. Settings can be backed up to your PassageMail account and restored onto any GO! device.
PassageMail uses a compressed burst sync protocol — one request up, one response down, everything gzip-compressed. Designed for the Iridium GO! at 9.6 kbps.
If a satellite connection drops during download, PassageMail saves every byte to disk. The next sync resumes exactly where it left off. A 300 KB chart package may take several satellite passes to complete — each pass picks up where the last one stopped. No data is ever wasted.
Enable Auto Login and Auto Data Connection in the Connect tab for unattended operation. The app will automatically connect and sync when an Iridium GO! is detected.
1,400+ active NOAA weather products across 4 ocean regions: Arctic, Atlantic (including Gulf & Caribbean), Great Lakes, and Pacific. Products include surface analysis, wind/wave forecasts, sea state charts, tropical cyclone advisories, ice analysis, satellite imagery, and text forecasts.
The catalog updates automatically over satellite or WiFi. Check your version in Settings → About.
PassageMail requests and delivers official NOAA weather charts directly from NOAA’s servers. Chart dates and validity periods are printed on each chart by NOAA. It is the responsibility of each user to read and understand all charts and forecasts, including validity dates.
Curated chart packages organized in three levels: categories, stations, and individual presets. NOAA Radiofax Stations include regional briefing packages with condensed and full versions.
Create your own custom presets from the Queue tab — they sync across all your devices.
How long does a sync take over satellite?
A message-only sync takes 30-60 seconds. With charts, expect 5-15 minutes depending on chart count and signal quality. The app shows real-time progress with KB counters.
What happens if my connection drops during a download?
PassageMail saves every byte received. The next sync resumes from where it stopped — no data is lost.
Do I need a southern sky view for the GO!?
No. Iridium uses 66 low-earth orbit satellites in a polar mesh that covers every direction. A satellite passes roughly every 9 minutes from any point on Earth. You do not need to point south.
Does weather affect satellite reception?
No. Iridium operates at L-band (1616-1626.5 MHz) which passes through clouds, rain, and fog. Only physical obstructions (walls, masts, sails) block the signal.
Why does Iridium GO! signal rise and fall?
Iridium satellites are in low Earth orbit, not fixed over one spot like geostationary satellites. Each satellite circles the Earth about every 100 minutes. From a boat, a given satellite is only useful for several minutes before the GO! hands the connection to another satellite. Smaller beam handoffs can happen about every minute. Short drops, pauses, or speed changes are normal on this type of link.
Does latitude affect Iridium signal timing?
Yes. Iridium uses near-polar orbits, so satellites converge toward higher latitudes. Equatorial and low-latitude passages tend to depend more tightly on clean handoffs. Higher latitudes often have more overlapping satellite visibility, although antenna placement, rigging, boat motion, and blocked sky still matter.
How does PassageMail use satellite timing?
PassageMail watches GO! signal, registration, connection state, and transfer progress. Automatic sync can wait briefly for a better signal window, while manual Sync Now still starts when you ask. If a transfer is interrupted, PassageMail resumes from the saved byte position on the next sync instead of starting over.
Will satellite prediction data use much bandwidth?
No. The Iridium satellite position data needed for prediction is small and can be cached. PassageMail can update it over regular internet when available, or receive a compact server-generated timing hint during normal sync. It should not materially affect chart or email transfers.
Can I use PassageMail offline?
Yes. Everything except sync works offline: browsing charts, reading messages, composing email, managing presets, and queuing chart requests. PassageMail is designed for offline-first operation.
How much does airtime cost?
Iridium prepaid airtime is approximately $1.40/minute. A typical message-only sync uses about 1 minute. Chart downloads vary by size — the app shows estimated download time for each preset at your link speed.
What Iridium devices are supported?
Currently the Iridium GO! (firmware 2.3.1+). Iridium GO! exec (Certus 100) support is planned.
Can I change my GO! WiFi password from the app?
Yes. Go to Connect → Iridium GO! Management → GO! Settings. You can read and set the WiFi password, SSID, and channel. The GO! must restart for security mode changes to take effect.
Email: support@passagemail.com
Website: passagemail.net
You can also compose a support message directly from the app: Help tab → User Manual → tap the support email link.