Communications Atlas
How to actually get weather underway — HF/SSB, Iridium, NAVTEX, satphone, and WiFi in port.
Offshore data tiers (fastest → slowest)
- Starlink Maritime / RV / Roam — full-bandwidth internet within ~100–200 nm of coast (and beyond with newer plans). Changes the game if you have it.
- Iridium GO!+ / Certus — low-bandwidth data, works anywhere. Saildocs via email over Iridium is the classic cruiser workflow.
- SSB + Pactor modem (Winlink) — free, no subscription, requires ham or marine SSB license. Email-based GRIB retrieval.
- NAVTEX — broadcast text (no request), coastal only, 518 kHz and 490 kHz.
- HF voice / radiofax — no transmit needed; receive-only works with a cheap SSB.
Saildocs over email (the cruiser workhorse)
Works over any email-capable link (Iridium, Winlink, satphone). Send an email with just the query in the body to query@saildocs.com. Full playbook with worked examples for Saildocs + ftpmail: Email Request Playbook.
Other useful Saildocs commands:
- send gfs:35N,50N,135W,120W|1,1|0,6..72|WIND,PRMSL — GRIB.
- send fzpn02.kwbc — high-seas text forecast (Pacific).
- send list — returns the catalog of available text products.
Winlink (email over SSB or Iridium)
NAVTEX
- 518 kHz — English, international.
- 490 kHz — local language.
- 4209.5 kHz — tropical extended range.
- Broadcasts gale warnings, nav warnings, and MSI on a schedule. Receiver-only; keep it on in the background.
USCG HF voice (no license needed to receive)
| Station | Area | Day freq (MHz) | Night freq (MHz) |
|---|---|---|---|
| NMN Chesapeake | W. Atlantic | 6.501 / 8.764 / 13.089 | 4.426 / 6.501 / 8.764 |
| NMG New Orleans | Gulf of Mexico | 8.764 / 13.089 | 4.316 / 8.764 |
| NMC Pt. Reyes | E. Pacific | 8.764 / 13.089 / 17.314 | 4.426 / 8.764 |
| NMO Honolulu | Central Pacific | 8.764 / 13.089 | 6.501 / 8.764 |