[aprssig] Telemetry question
hessu at hes.iki.fi
Sat Aug 16 04:43:48 CDT 2008
On Fri, 15 Aug 2008, Alan P. Biddle wrote:
> Now, I would like to find out how to upload the data over RF into the system
> so that someone just going to a site such as APRS.FI will automatically see
> the data without the complicated URL. Here is an example of what I am
> trying to do:
> I have asked about how to do that various places, and gotten answers such as
> "you can do that in the beacon message" or "you broadcast the parameters
> according to the APRS spec on RF," (Operator of APRS.FI.) or "you could do
> that with my unit's scripting language." (Which in the last case does not
> yet exist.) No doubt true, but not overly helpful if you don't really know
> what you are doing. Ahem.
I'm sorry about that - I'll try to answer in a more helpful method this
As others pointed out, you need to send the equations and parameter
names in an APRS message. You can send them from another APRS
client/device/program than the actual device sending the telemetry, it
just needs to be able to do APRS messaging (the one-liner "chat" messages
you can read at http://aprs.fi/?c=message for example). I have to admit
that aprs.fi had a bug here - it didn't allow updating another station's
equations until today, but I've fixed that now.
The telemetry device's callsign goes to the *destination* field of the
message (not the AX.25 packet callsign, which can be just about anything,
but the destination field of the messaging format). The PARMS/EQNS/UNIT
message goes in the content of the text message.
Start UI-view, or another program capable of sending APRS messages to
other users, start a chat with the tracker which is sending the telemetry
(click on Messages in UI-View32), and type in the EQNS/PARMS/UNIT
> BITS.00000000,NOTHING HERE....
That should work. You can look at the raw packets received at aprs.fi,
both yours and another station's which is sending these correctly, for
2008-08-16 09:00:42 UTC: VK5RAC-1>TLM,EYRE2-2,qAR,VK5ZEA::VK5RAC-1 :EQNS.0,0.5,0,0,0.1,0
2008-08-16 09:01:53 UTC: VK5RAC-1>TLM,EYRE2-2,qAR,VK5ZEA::VK5RAC-1 :PARM.Temp,Battery,TX
2008-08-16 09:03:06 UTC: VK5RAC-1>TLM,EYRE2-2,qAR,VK5ZEA::VK5RAC-1 :UNIT.Deg.C,Volts,PTT's
The source callsign can be anything (the first VK5RAC-1 there), as long
as the message destination (after the ::) is the telemetry station's call.
- Hessu, OH7LZB
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