[amsat-bb] introduction and request for information (APRS EMAIL)
bruninga at usna.edu
Thu Dec 1 20:41:31 UTC 2016
> What I want to do next is basically email myself over RF via space.
> I'd prefer to have an antenna that wouldn't need to track.
> [and] limit myself to passes over X deg (say 30) to get short ranges...
Its easy. Use any AX.25 1200 baud packet system on 145.825 MHz when the
ISS comes over several tiems a day and send this packet:
URCALL>APRS,ARISS::EMAIL....:UREMAIL at WHATEVER.WHATEVER hi world this is
The first part is the header built by your packet modem or software
showin your SENDING call, the destination address of APRS and the VIA path
The body of the packet must begin with :EMAIL....:
Which tells APRS it is a "message format. The extra 4 dots shoule be
spaces to pad the message address field out to a total of 9 characters.
Then immediately following that is the body of an APRS message. In this
case, to have it become email, you have to begin the message with the
FIRST "word" being the complete email address. In the example, I wrote
that as UREMAIL at WHATEVER>WHATEVER
And then after a space to separate it, is your actual text of your email.
All of this is in one packet, and the sum total of the length of y our
email address and the text of yoru email must fit in the APRS message size
of I think it is 67 bytes.
CAVEAT: All of the above assumes the ISS is on 145.825 MHz (I think it is
not. I think It is now on 437.550 MHz which requires you to track Doppler
in a complicated fashion stepping up in transmit frequency while at the
same time stepping down in frequency for receive during the pass.
Also it assumes the global APRS "EMAIL" engine is on line and working...
ALSO it assumes the ISS digipeater address is still working as ARISS. If
not, you may have to use the actual call of RS0ISS if that is what it is.
Search for APRS EMAIL and you should be able to find something.
More information about the AMSAT-BB