3/20/2018

APRS - sending SMS message



SMS message from APRS

I was looking for a way to send a text message in the both direction from / to amateur radio.  The one I mentioned in the previous post is one-way communication from an amateur radio to a mobile device via E-mail.   We cannot reply to the message on the mobile device side.   That is a big limitation for the communication.

After I checked the web site of APRS, there is another service through SMSGTE (APRS/SMS Gateway).   This method provides communication in the both direction with some limitation.  I think it works.

Here is how it works:

  1. Using "SMSGTE" instead of a call sign when people send a message
  2. In a message body, inserting "@xxxxxxxxxxx " (xxxxxxxxxx is a phone number) to specify the destination of SMS message.
As long as the packet is going through to APRS-IS via IGATE station, a message can be delivered to a mobile device.   Also the person who received the message can reply to the message with in 30 minutes from the last message.   I tested this scheme in some different location with disabling cellular network data.  Now this might be a way to send a message even if a cellular network is out of the range.  Now APRS is probably very useful on a trail during hiking.

If you carefully look into the site, the service is provided in limited region.  The United States is one of countries where the service is available.

  • We can send out a location information periodically and people can trace the location from the internet.   (To trace the location history, no amateur license is required)
  • We can tell stations who is close to the current location.   Call-signs are listed and they can exchange messages each other.  It is probably useful to contact those station in case people needs some assistance.
  • We can send SMS message to any mobile device. (limited countries)
To use APRS, people need to get amateur radio license, but I think it worth to get it.   It helps a lot in case something happens during hiking in an area where a cellular service is not available.

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