[amsat-bb] ISS APRS with an HT

Thu Mar 26 23:31:56 UTC 2020

It’s all good. I have found this discussion very enlightening in how the
APRS network actually works. Back to my original problem, I am guessing
that when the ISS is passing over that if it does receive my packets then
there may not be an iGate nearby that can digipeat it back to the larger
APRS network. As to whether I accidentally transmitted on the normal APRS
frequency, I can’t rule that out and it may have happened on accident
because in my radio that memory is next to the ISS APRS memory. Therefore
an accidental slip of the finger while holding the radio would accidentally
turn the knob and adjust the memory.

On Thu, Mar 26, 2020 at 7:20 PM Scott via AMSAT-BB <amsat-bb at amsat.org>
wrote:

> >>> W4GCW says he does not listen on the ISS frequency
>
> Were you perhaps transmitting on 144.390 at some point & that's why he's
> shown as the iGate on the screen capture I posted?
>
> https://www.qsl.net/k/k4kdr//images/KO4AQF-digipeats.png
>
> ... that would explain it, so very sorry for any confusion that I might
> have caused.
>
> On a related note, for anyone running an iGate with Direwolf, the directive
> "SATGATE 15" can be helpful by putting a 15 second delay on your upload of
> heard packets.  That way, if you happen to hear something from a neighbor
> directly (but his packet IS digipeated via satellite), some other iGate
> will likely hear the digipeat from space and upload that before your iGate
> gets around to uploading the locally heard packet.  The end result is that
> your locally-heard packet is discarded as a duplicate and what shows on the
> APRS network is the digipeated packet -- a much better outcome!
>
> -Scott,  K4KDR
>
> ==============================
>
> On Thu, Mar 26, 2020 at 6:40 PM Brian Wilkins KO4AQF <bwilkins at gmail.com>
> wrote:
>
> > In the past day, I have been working with W4GCW and KJ4EJR (author of
> > APRSIS32 and APRSISCE who lives in my County)
> >
> > There is no way not to filter based on callsign and his software is
> > compliant to the APRS-IS specification. Therefore, there is no way to
> > prevent the iGate of my messages. W4GCW says he does not listen on the
> ISS
> > frequency and rather the standard APRS frequency. Below is a response
> from
> > KJ4EJR when I asked him if it’s possible to filter out my packets.
> >
> > “per the IGate specs at http://www.aprs-is.net/IGateDetails.aspx
> >
> > Gate all packets heard on RF to the Internet *EXCEPT* if any of the
> > following are true:
> >
> >    1. (AX.25 RF) The packet does not have a control field of 0x03 or a
> >    PID of 0xf0.
> >    2. The TNC has PASSALL turned on.
> >    3. 3rd-party packets (data type } ) with TCPIP or TCPXX in the 3rd
> >    party header.
> >    3rd-party packets without TCPXX or TCPIP mnust have the RF header and
> >    the 3rd party data type stripped before passing to APRS-IS.
> >    4. generic queries (data type ? ).
> >    5. packets with TCPIP, TCPXX, NOGATE, or RFONLY in the header (last 2
> >    are optional).
> >
> > You will notice that there is NOT any option for blacklisting or
> otherwise
> > not forwarding RF-received packets to the APRS-IS for spec-compliant
> IGate
> > operation.“
> >
> > On Wed, Mar 25, 2020 at 9:33 PM Brian Wilkins KO4AQF <bwilkins at gmail.com
> >
> > wrote:
> >
> >> That makes sense to me and I will contact him. He is my neighbor. What I
> >> am not clear on is why all of a sudden it stopped working when it was
> >> working prior to the ISS APRS shutdown. It may also explain why when I
> see
> >> you (K4KDR) and send messages via the ISS (or what I am told is being
> >> digipeated because my radio gets a message that the ISS received it) you
> >> never see them. I have been trying off and on for a couple months now to
> >> reach you. I have successfully reached N1RCN on multiple occasions.
> >>
> >>
> >> On Wed, Mar 25, 2020 at 8:59 PM Scott via AMSAT-BB <amsat-bb at amsat.org>
> >> wrote:
> >>
> >>> Hi Brian & everyone.
> >>>
> >>> Websites like ARISS.net monitor the APRS traffic and display a list of
> >>> packets that match certain criteria.  In the case of a site that wants
> to
> >>> display packets digipeated via the ISS, they're looking for "RS0ISS*",
> >>> which is appended to the digipeat path of a packet that is relayed thru
> >>> the
> >>> ISS.
> >>>
> >>> When it works correctly, you transmit a packet that is digipeated by
> the
> >>> ISS and the digipeat from the ISS is heard by an iGate that puts it
> onto
> >>> the internet for sites like ARISS.net to display.
> >>>
> >>> However, generally speaking, the APRS network is designed to toss out
> >>> "duplicate" packets.  And as you might imagine, it's
> >>> first-come-first-served.
> >>>
> >>> If you'll notice on the following link to a screen shot:
> >>>
> >>> https://www.qsl.net/k/k4kdr//images/KO4AQF-digipeats.png
> >>>
> >>> ... the vast majority of your packets are being heard DIRECTLY by in
> >>> iGate
> >>> run by W4GCW.  So, a good portion of the time, when you get digipeated
> >>> via
> >>> the ISS, the APRS network considers that a duplicate and it's
> discarded.
> >>> YOU (and others) might hear it off the air, but it'll never show up
> >>> online
> >>> anywhere.
> >>>
> >>> In the same image you can contrast those locally heard packets with
> >>> packets
> >>> that were digipeated & uploaded by iGate's KE4AZZ-3 & KC5ILO-12... of
> >>> course that's how it's supposed to work.
> >>>
> >>> You might want to reach out to W4GCW to see if he'll filter out your
> call
> >>> sign on his iGate to give your digipeated packets a chance to be heard
> by
> >>> an iGate and get forwarded onto the greater APRS network as DIGIPEATS
> >>> (instead of being discarded as duplicates).
> >>>
> >>> -Scott,  K4KDR
> >>>
> >>> ==========================
> >>>
> >>> On Wed, Mar 25, 2020 at 7:30 PM Brian Wilkins KO4AQF via AMSAT-BB <
> >>> amsat-bb at amsat.org> wrote:
> >>>
> >>> > I had no issue until it went offline and then came back. I believe
> one
> >>> of
> >>> > the iGates near me may have went offline since the ISS APRS pause as
> >>> ISS is
> >>> > confirming my messages however nothing is showing up on ariss.net
> and
> >>> I
> >>> > can
> >>> > exchange messages with others. I am considering building my own APRS
> RX
> >>> > iGate from an RTLSDR and Raspberry Pi just to digipeat my own packers
> >>> back
> >>> > to APRS.fi website
> >>> >
> >>> > On Wed, Mar 25, 2020 at 7:22 PM John Brier via AMSAT-BB <
> >>> > amsat-bb at amsat.org>
> >>> > wrote:
> >>> >
> >>> > > I got through it on March 21st on a 12 degree pass using a TH-D72
> >>> and an
> >>> > > Arrow:
> >>> > >
> >>> > > https://twitter.com/SpaceComms1/status/1241598936814694400?s=19
> >>> > >
> >>> > > It was hard, as I believe it is a little deaf or not decoding
> >>> > consistently
> >>> > > based on past reports. Some have said it seems to be easier with
> >>> Kenwood
> >>> > > radios.
> >>> > >
> >>> > > They are sending up a new Kenwood radio system soon that supports
> >>> > > digipeater ops so don't dismiss this mode entirely!
> >>> > >
> >>> > > 73' John Brier KG4AKV
> >>> > >
> >>> > > On Wed, Mar 25, 2020, 19:02 Steve Kristoff via AMSAT-BB <
> >>> > > amsat-bb at amsat.org>
> >>> > > wrote:
> >>> > >
> >>> > > >
> >>> > > >  Has anyone been able to digipeat APRS through the ISS with a 5
> >>> watt HT
> >>> > > > and an Arrow antenna lately? If so, what are your secrets for
> >>> success?
> >>> > > > If 5 watts and an Arrow doesn't work please let me know that,
> too,
> >>> so I
> >>> > > > can pursue a different aspect of our hobby.
> >>> > > > thanks!
> >>> > > > Steve AI9IN
> >>> > > > Grid EM79ji
> >>> > > > Oldenburg IN 47036
> >>> > > >
> >>> > > > _______________________________________________
> >>> >
> >>>
> >>
> >
> _______________________________________________
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-- 
Brian Wilkins
KO4AQF