Sending a message to a group - spec!

Lynn Deffenbaugh

Ok, I thought about this some more and remembered something about message groups which was sort of mixed up with private nets in my mind. I went back to the aprs101.pdf spec and found the following on page 72:

Message Groups:
An APRS receiving station can specify special Message Groups, containing lists of callsigns that the station will read messages from (in addition to messages addressed to itself). Such Message Groups are defined internally by the user at the receiving station, and are used to filter received message traffic.

The receiving station will read all messages with the Addressee field set to ALL, QST or CQ. The receiving station will only acknowledge messages addressed to itself, and not any messages received which were addressed to any group callsign.

Note: The receiving station will acknowledge all messages addressed to
itself, even if it is operating in an Alternate Net (see Chapter 4: APRS Data in the AX.25 Destination and Source Address Fields).

If I read this correctly, I would need to add "additional received message" callsigns which will cause any received messages for any of those callsigns to be displayed. I've also read that the Kenwood radios automatically display any messages addressed to the base callsign regardless of SSID for your own call. Finally, it seems that ALL, QST, and CQ are always on the "additional received message" callsign list.

I'll add this to the ToDo list and see what I can do when I get around to beefing up the received message and bulletin section of the client.

Lynn (D) - KJ4ERJ

The only "group" APRS messaging feature that I'm aware of is via the
CQSRVR. If you and everyone else send a message to the CQSRVR with an
agreed-up group ID, every subsequent message sent to that group will be
sent to all members. However, CQSRVR does have a minimum time limit for
any single message sender to the group.

See CQSRVR documentation at:

Maybe there's another "group messaging" feature in the Kenwood firmware
or UI-View, but I'm not currently aware of it and haven't noticed it in
any of the APRS specs that I've read.

Lynn (D) - KJ4ERJ

g4ilo wrote:
I would like to send an APRS message that would be received by anyone who wants to receive it. The only way I know how to do this is for everyone who wants to receive the message to tell me their call-ssid and I send the message individually to each of them.

I seem to remember reading somewhere that it is possible to send a message to a group name and individuals can then choose to receive those messages. For example it appears people can choose to receive NWS messages. But I can't find any information on how to do it. Is my recollection correct, and if so how do I go about it? And is anything special needed to originate a message to the group as distinct from receiving it?

Julian, G4ILO


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