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eHam Forums => APRS => Topic started by: N1KTJ on February 05, 2013, 02:42:54 AM



Title: aprs messageing - dumb terminal only
Post by: N1KTJ on February 05, 2013, 02:42:54 AM
does anyone have a reference for doing dumb terminal aprs messaging?  specifically what the message structure has to be for area aprs repeaters to pick the message up a repeat it eventually to a gateway?  cant seem to find a reference.


Title: RE: aprs messageing - dumb terminal only
Post by: W4KYR on February 05, 2013, 06:56:28 AM
does anyone have a reference for doing dumb terminal aprs messaging?  specifically what the message structure has to be for area aprs repeaters to pick the message up a repeat it eventually to a gateway?  cant seem to find a reference.

I'm also looking for information along the same lines except using those mobile data terminals that they sell on E-Bay next to nothing  for possible packet/APRS uses and/or as dumb terminals. One of the MDT's I saw (think it was a Pyramid) had GPS capabilities as well...saw an asking prices under $50 and could have been used for APRS .

You can use hyperterminal with an old MFJ 1278 as a digipeater and send it somewhere else.



Title: RE: aprs messageing - dumb terminal only
Post by: KG6HXO on February 06, 2013, 06:38:40 AM
I can't find any $50.00 mobile terminals on E-bay; How are they listed?

73,

Allen AF6OF


Title: RE: aprs messageing - dumb terminal only
Post by: K0JEG on February 06, 2013, 05:58:03 PM
does anyone have a reference for doing dumb terminal aprs messaging?  specifically what the message structure has to be for area aprs repeaters to pick the message up a repeat it eventually to a gateway?  cant seem to find a reference.

Here's a fairly good explanation of how it works: http://aprsisce.wikidot.com/doc:aprs-messaging-explained

If we look at the raw data I just generated by sending a message from my TH-d72 to APRS Droid:

Code:
K0JEG-2>APK003,OLYS,WIDE1*,WIDE2-2,qAR,GWS::K0JEG-5  :hello{7

The first part is the standard routing from all the stations that digipeated and passed the message to the gateway, normal stuff. Notice the double colons ( :: ) then the recipient station's call (in this case K0JEG-5) and another colon. Anything that follows the single colon is text message until the {7 which is basically an EOL.

Note that several things need to happen on the gateway end for this all to work. 1st is the gateway has to be configured to gate message traffic from the Internet to RF. Next the gateway has to have heard from your station and gated it recently so that the APRS-IS knows where to route the message. The actual packet is fairly simple, just the :: and callsign makes it work.

One interesting side note. I stumbled on this when looking for a better explanation: APRS messaging to email! http://www.aprs-is.net/email.aspx That's wild!


Title: RE: aprs messageing - dumb terminal only
Post by: KE4NYV on April 03, 2013, 12:04:58 PM
One option that you might want to consider is the OpenTracker USB or Tracker 3 that both have a command line interface.  This is great for setup, but they also both have a MESSAGE command that allows you to send an APRS formatted message right from the command line interface.  I would have to look up the exact syntax, but I think it's something as simple as:

SEND KE4NYV-5 Message Text

The callsign is the destination callsign of the station you want to send the message to.

EDIT:  Here is a link to the manual:  http://www.argentdata.com/support/OpenTrackerUSB_manual.pdf

The command is actually SEND, not MESSAGE or MSG.