Winlink — Ham Radio Email Without the Internet

What Winlink Is

Winlink (winlink.org) is a worldwide radio email system operated by the Winlink Development Team and used extensively by amateur radio operators and maritime mobile operators. It allows licensed operators to send and receive standard email messages over radio frequencies — without requiring an internet connection at the transmitting station. The radio path carries the message to a Winlink gateway station (called a Radio Message Server or RMS) that is internet-connected; from there, messages travel the internet to their destination.

In an emergency where local internet is down but radio propagation is intact, Winlink allows a shelter, EOC, or field team to send email to any address in the world using nothing but a radio, a computer, and a modem or sound card interface.

How It Works

The basic chain: your radio transmits a packet containing your email to a nearby Winlink RMS gateway station. The RMS receives your packet via radio, then uploads it to the Winlink CMS (Common Message Server) over the internet. The CMS delivers it to the recipient's email address. Incoming email to your callsign@winlink.org address is stored at the CMS and downloaded to your radio station the next time you connect to an RMS.

Technician Class operators can use Winlink on VHF/UHF frequencies — specifically on 2-meter packet (144.39 MHz is APRS; dedicated Winlink VHF gateways operate on other local frequencies, typically around 145.0–145.8 MHz). General Class operators have access to HF Winlink gateways that function over much longer distances when local VHF gateways are unreachable.

Equipment You Need

For VHF Winlink (Technician accessible):

• A 2-meter capable radio (any VHF HT or mobile transceiver)
• A TNC (Terminal Node Controller) or a sound card interface (SignaLink USB, $120, or Digirig, $60)
• A computer running Winlink Express (free software from winlink.org)
• A Winlink account registered at winlink.org (free, requires your call sign)

For HF Winlink (General Class and above), add an HF transceiver and HF antenna.

Winlink in Emergency Operations

FEMA and the American Red Cross have endorsed Winlink as a backup communications system. During Hurricane Katrina, Superstorm Sandy, and numerous California wildfires, Winlink provided email connectivity for served agencies when commercial internet was unavailable for days. ARES groups across the country train on Winlink regularly and many county EOCs have pre-positioned Winlink-capable stations.

Getting Started with Winlink

1. Create a free account at winlink.org using your call sign
2. Download and install Winlink Express (free at winlink.org/WinlinkExpress)
3. Find a local VHF Winlink RMS gateway at winlink.org/RMSChannels — search by your grid square
4. Connect your radio to your computer via a sound card interface
5. Configure Winlink Express for Winlink over Packet (VHF) mode
6. Initiate a session to the local RMS — Winlink Express handles the handshake automatically

• Can I send Winlink email to non-ham email addresses?
  Yes. Winlink delivers to any standard email address. The recipient does not need a ham license or Winlink account — they receive a normal email from your callsign@winlink.org address. You can reply to messages from non-ham addresses. Winlink bridges the amateur radio network to the standard internet email system seamlessly.
• Is there a size limit on Winlink messages?
  Yes. Winlink messages are limited to approximately 120KB including attachments on radio paths. This is sufficient for text messages, ICS forms, and small image attachments but not for large files. The size limit exists because radio bandwidth is limited compared to internet bandwidth — a 120KB message over a 1200-baud packet connection takes about 8 seconds to transfer.
• What is the difference between Winlink and APRS?
  APRS (Automatic Packet Reporting System) is primarily a real-time position and status reporting system — it broadcasts your GPS location, weather data, and short messages to anyone monitoring. Winlink is an email system — it passes longer formatted messages point-to-point with store-and-forward delivery. Both use packet radio technology, but they serve completely different purposes and operate on different frequencies and protocols.