[aprssig] APRS Email from Space! (ET Phone Home)

Robert Bruninga bruninga at usna.edu
Sun Jun 30 08:54:51 EDT 2019

As I explained before, when Pete raised his objection back in March, it was
already after PSAT2 had gone through software certification and was less
than a month to delivery when it is impossible to change flight software
after all space qualification testing has completed.

PSAT2 received its IARU coordination in 2015 and was built in 2016.  The
Brno PSK31 and SSTV modules from Brno university were integrated in  March
2017., and space qualification testing was completed for an April 2017

Then two years of incremental launch delays just one or two months at a
time brings us to here.  In March I contacted you to let you know that the
Sproul Brothers had agreed to release the original "EMAIL" address and I
asked if you wanted to support it (in addition to your EMAIL2 engine).

I wanted to make sure an "EMAIL" engine existed because that was what was
already programmed into PSAT2 and could not be changed.

When you objected to my experiment, it was too late and there was nothing I
could do to change the experiment.   So do not think that I simply ignored
your objections.  It was just too late and I had enough other things that
urgently needed attention and so no need to keep arguing.

The main APRS value is being a one-to-all packet distribution system.  But
with one exception, messages.  And so the APRS design included the ability
to send one-to-one messages as well to cut down on unnecessary "broadcast"
when there was a single intended recepient.  It also included an optional
line number in case the sender wanted to get an ACK.

PSAT2 uses an un-numbered APRS message format to send me an EMAIL status
once a day so that I can be aware of its status wherever I can receive
email.  It depends on a working "EMAIL" engine to pull that status report
from the APRS-IS and forward it to my email address.

You deserve thanks for providing all the support for the APRS-IS over all
these years and for supporting the EMAIL engine.

Bob, Wb4APR

On Sun, Jun 30, 2019 at 7:42 AM Pete Loveall AE5PL Lists via aprssig <
aprssig at lists.tapr.org> wrote:

> And this is why I am sad to see you went ahead with this against my talks
> with you (initiated by you, BTW) before the launch.
> It is SPAM when you are trying to do something with an email server that
> it was specifically designed not to do.  As stated before to you,
> APRS/email servers rely on numbered messages to differentiate between
> messages, acknowledge those messages, and to report to the sender the
> status of the emails being sent.  None of those 3 premises are supported by
> your satellite.
> Your statement about the APRS protocol or FCC rules not prohibiting
> inanimate satellites from transmitting packets is nonsensical.  I never
> said it was prohibited.  I said your use of the numbered messaging protocol
> by using static numbered messages to try to broadcast a message to a
> station (the email server) without supporting acks and without supporting
> received numbered messages is breaking the APRS protocol.
> Yes, the numbered message definition in the APRS spec relies on
> bidirectional communications.  If you were to use unnumbered messages that
> do not require bidirectional communications, the email servers would not
> respond to unnumbered messages.  Contrary to your claim that the code could
> not be changed from over a year ago, you first approached me with this
> concept earlier this year using unnumbered messages.  I told you at that
> time that email servers depend on the bidirectional nature of numbered
> messages to differentiate between messages, to acknowledge receipt of the
> messages, and to provide information to the sender on the status of the
> email generation/delivery.  Since you are using numbered messages, I assume
> you made the change in the code and ignored my admonishment that using
> numbered messages from a device that is not able to receive or properly ack
> responses was, in essence, an abuse of the protocol and the email servers.
> Or maybe you just made the satellite capable of sending any message you
> define on the fly and so you are just broadcasting a predefined numbered
> message which is even worse.
> If you didn't want this discussion, maybe you should have thought about
> what I explained to you in the first place before the launch.
> 73,
> Pete Loveall AE5PL
> pete at ae5pl dot net
> -----Original Message-----
> From: Robert Bruninga <bruninga at usna.edu>
> Sent: Saturday, June 29, 2019 11:15 PM
> To: TAPR APRS Mailing List <aprssig at lists.tapr.org>
> Subject: RE: [aprssig] APRS Email from Space! (ET Phone Home)
> Pete,
> An APRS Email is not spam when it is a point-to-point email from our
> satellite to me reporting its status.  A vital function.
> There is nothing in the APRS protocol or FCC rules that prohibits inanimate
> amateur satellites from transmitting packets.
> Further, there is nothing that requires bi-directional APRS Message
> packets.
> The protocol was designed to allow APRS messages *without* line numbers so
> that bi-directional acks were not required.  This was to declutter the
> channel when the path was unreliable.
> And the satellite code was finished more than a year ago when the satellite
> was finished, and began space qualification testing.  Once it passed all
> vibration and other space quals and final performance checks,  one *cannot*
> change the code or it invalidates all the space qualification testing.
> Bob Bruninga, WB4APR
> _______________________________________________
> aprssig mailing list
> aprssig at lists.tapr.org
> http://lists.tapr.org/mailman/listinfo/aprssig_lists.tapr.org
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