Sending a text message or an email over APRS
This post is for emergency communications and off-grid operators who have an APRS station and need to reach someone who does not: a phone, an email inbox, or a Winlink account. Three gateways on the APRS network do that job, and each wants something different from you before it will relay a message. Everything here works over APRS-IS in the free app; none of it needs APRS Connect Pro.
It covers what each gateway reaches, what you must arrange first, how APRS Connect presents each as a guided page with a form per command, and where the replies end up.
The three gateways at a glance
| Gateway | What it reaches | What you need first | Where replies land |
|---|---|---|---|
SMS (answers as the callsign SMS) | A mobile phone, as a text message | Both phone numbers opted in at aprs.wiki | An ordinary thread on the Messages tab, one per number |
Email (EMAIL-2) | Any email address, one line per packet | Nothing beyond a working APRS station; a saved shortcut helps | The service's thread on the Messages tab |
Winlink (APRSLink, WLNK-1) | A Winlink mailbox, send and manage | A Winlink account, and at least one position beacon from your callsign | The service's thread on the Messages tab |
All three are free to use. All three go out in the clear: APRS is a public network, and the traffic is archived by sites such as aprs.fi.
SMS: texting a phone
The current SMS gateway answers as the callsign SMS. The older SMSGTE gateway has shut down and no longer answers, and APRS Connect does not list it.
One rule stops most first attempts: both phone numbers must opt in at aprs.wiki before the gateway will carry a text between them. An unregistered number is refused with a reply saying the number has not opted in. If you are planning for an emergency, do the registration now rather than on the day.
A text to a number is sent to SMS as @<number> <message>, with the number written as digits only. You can also save a short lowercase name for a number on the gateway itself and then text @<alias> <message> instead. The alias lives on the gateway, not on your phone, so it works from any radio you use. A separate command checks for texts that arrived while you were off the air.
Each gateway command is a form; the packet it will send can be shown before it goes.
In APRS Connect, texts are ordinary conversation threads on the Messages tab, with their own SMS kind in the thread filter, and they get the same unread counts, notifications, search, archive and delivery tracking as a conversation with another station. The thread states that it is sent in the clear over APRS. From its menu you can either give the conversation a local name on your phone, which transmits nothing, or save the number as an alias on the gateway. Only the gateway alias works as an address, which is why the two are kept apart.
Email: one line through EMAIL-2
The EMAIL-2 gateway turns one APRS message into one line of email. The address goes first, followed by the text, and the two together share the 67-character APRS message limit. That is why the gateway supports saved shortcuts: you send a message pairing a short name with an address, and from then on the short name stands in for the address and leaves far more room for the message. A shortcut also lets that address email you back over APRS, and a separate command fetches waiting mail.
The gateway expects numbered messages and acknowledgements, and stations that transmit in the blind may be blocked. Do not point it at automated responders or Winlink nets. Third-party traffic rules apply per country.
Winlink: a mailbox through APRSLink
APRSLink (WLNK-1) lets you send and manage Winlink email from an APRS station. It needs a Winlink account, and it will not answer until it has seen at least one position beacon from your callsign, so send a beacon before your first command.
Its commands include a one-line send, a listing of pending messages (up to five, numbered), and reading, replying to, forwarding or deleting a message by its number. There is also a multi-line send, which opens a message with a subject and takes the body as further messages until you close it. Use the one-line send for a short note; the multi-line form leaves a draft open on the server until it is closed.
How the app presents them
The Services tab holds a directory of 22 APRS service bots, and every one gets a page that says what it does, who runs it, and offers a form for each command. You fill in a recipient and a message and the app builds the packet. With Show APRS commands turned on in Settings, the service page shows the full command before it goes. You can also type a command by hand instead.
Replies from any gateway thread back on the Messages tab with the same delivery tracking as any other message. Relayed texts land in the conversation with the number.
Reachability
Not every service is reachable from every station. A reachability note on the service page warns when a service appears to be RF-only or offline and a reply may not come. It warns without blocking, because you know your own path better than the app does. Services that have not been verified against the live bot are labelled UNCONFIRMED in the directory.
Where to read more
- APRS services, the full directory and the reachability note.
- Messaging, the threads that gateway replies land in and the six delivery states.
- Send your first beacon, which APRSLink requires before it answers.
- Connect to APRS-IS, enough to reach all three gateways.
None of this needs APRS Connect Pro; the gateways are part of the free app over APRS-IS.
