Winlink: Sending Email by Radio When the Internet Is Down
What a blackout lacks is not voice — it is recordable text
Voice hits its ceiling quickly in emergency work. An address, a string of numbers, a casualty status form: copy them by ear, relay them once, and the error rate climbs fast.
What you actually need is text that can be recorded accurately, carry attachments, and be forwarded verbatim. That is exactly what email is good at — the problem is that after the network dies, email cannot move.
Winlink’s job is to move email onto radio.
What it is
Winlink Global Radio Email is a worldwide radio mail network of amateur stations and authorized government stations, providing mail paths where the internet is not present. The system is built, operated and administered entirely by licensed volunteers, with support from the Amateur Radio Safety Foundation (ARSFI), a US non-profit.
It supports email with attachments, position reporting, weather and information bulletins, and is widely used in interoperable emergency and disaster communications. Your address is your call sign at winlink.org, and a message including attachments may be up to about 120 KB.
The key property: it can run fully automatically without the internet, using a smart network of radio relays.
Three layers
Understanding Winlink takes three layers:
- Client — the program on your computer: Winlink Express on Windows, or Pat on Linux and macOS. This is where you write mail
- RMS gateway (Radio Message Server) — a volunteer-run, around-the-clock radio station with one foot on radio and one on the internet, feeding your mail into the mail system
- CMS (Common Message Server) — the central servers in the cloud that store mail and bridge to the internet mail system
The normal path: your radio, then the nearest RMS gateway, then the CMS, then the recipient’s mailbox. Replies return the same way.
The part that matters most: peer-to-peer
What makes Winlink irreplaceable in emergency work is P2P mode.
Two Winlink-equipped stations can exchange mail directly over the air — no gateway, no server, no internet. When nothing else exists, this is the only option that still holds.
Many emergency plans write P2P into their procedures explicitly: when the local gateway is unreachable and every conventional infrastructure is down, two radios can still pass a form between them.
Which mode
Different bands use different modulations; the choice comes down to distance and hardware budget.
On HF:
- VARA HF — the current mainstream. A software modem needing no dedicated hardware, with strong performance; up to roughly 8,000 bit/s under ideal conditions, while 2,000 to 4,000 bit/s is the realistic daily figure. Receive is free; the transmit license is a one-time fee
- ARDOP — free and open source, topping out around 1,336 bit/s. Slower than VARA, and usage is declining
- PACTOR — a hardware modem, the best performer in very poor conditions, but expensive; mostly found at well-funded emergency stations, with the current SCS P4dragon priced on the order of $2,000
On VHF/UHF:
- Packet (AX.25) — classic packet radio at 1200 baud: simple, reliable, the easiest starting point
- VARA FM — optimized for FM, faster than the HF variants
- VARA AC — a newer variant designed for fast channel access on FM repeaters and gateways
For a newcomer, the sensible combination is VARA HF on shortwave and VARA FM or Packet on VHF/UHF.
Hardware: three paths
- Path A — modern radios with a built-in USB sound card. Machines like the IC-7300, IC-705 and FT-991A include USB audio and CAT control; one USB cable and you are running. The least-effort option
- Path B — an external audio interface. Older radios need one; compact units like the Digirig travel well, while a SignaLink USB is sturdier, with level controls and PTT switching
- Path C — a TNC for packet. If you only intend to run packet on VHF, a TNC is sufficient
ICS forms: the feature that actually gets used
One of Winlink’s most practical emergency features is sending standardized forms as structured messages.
Winlink Express ships with templates including ICS-213 (general message), ICS-214 (activity log) and ICS-309 (communications log), plus Red Cross damage assessment forms. On the receiving end they render as proper forms and drop straight into the command structure’s workflow.
A filled ICS-213 delivered by radio to a command post matters because it is an official record — archivable, searchable, citable — not a voice exchange that has to be remembered and retold.
Getting started
- Register at winlink.org with your call sign, free of charge. Your call sign is your address
- Install the software: Winlink Express, plus VARA HF and VARA FM (basic versions free). Mac and Linux users can use Pat
- Connect the radio: either a radio with built-in USB audio, or an interface box; configure sound card and CAT control in the software
- Test in normal times: use the channel selector to find an active RMS gateway, make one connection under good conditions, and send a test message to yourself to confirm the whole path
- Drill P2P once: find a local operator and exchange one mail with no internet involved at all
The last two matter most. Winlink is a skill you maintain in peacetime. Starting to learn it on the day you need it almost guarantees failure.
Two maintenance details
An account is not permanent once registered. Winlink accounts only stay active through client connections via radio or telnet — webmail access does not count — and accounts off the air for roughly 400 days are purged automatically.
Eligibility requires a valid amateur license. GMRS, land mobile (LMR), ship station and other marine or general radiotelephone licenses do not qualify.
Many ARES groups run regular Winlink practice nets, with “send a standard form to the group address” as a standing exercise. That is the low-effort way to stay fluent.
How it relates to voice nets
Winlink does not replace voice.
Voice is for real-time judgment, coordination and on-scene decisions; Winlink is for information that must leave a record, must be exact, and may have to be shown to outsiders. In real operations they divide the work: what can be settled by talking gets talked through; what must be written goes by Winlink.
Once that division is clear, it is obvious why emergency teams train both.
References
- Winlink Global Radio Email (winlink.org) — system overview, account rules, RMS and CMS structure
- Winlink Development Team, Winlink Express (winlink.org) — supported modes, P2P connectivity, ICS-309 reporting
- OERadio, Winlink: Email via Radio — Emergency Communication Without Internet (accessed October 2026) — mode comparison and hardware paths
- ARRL, ARES Field Resources Manual (rev. 2019) — message handling and traffic net context