[amsat-bb] Cleaning up the Global APRS Satellite ground station network?

Scott scott23192 at gmail.com
Tue Aug 8 04:44:12 UTC 2017

Thanks for always thinking of ways to enhance the great APRS system, Bob.

I originally became a member of the "iGate Club" back when the ISS
digipeater temporarily transitioned to UHF.  With the initial shortage of
iGates on 70cm and plenty of SDRs & Raspberry Pi computers in the house, I
did my best to follow the online documentation on how to setup an RX-Only
iGate.  It was quite a thrill to see my K4KDR-10 iGate submit a respectable
number of digipeated packets to ariss.net.

Since the return to 145.825, my setup has not been as effective but I'll
look forward to being a better contributor as more satellites (not to
mention a repaired ISS digipeater) become active on 2 meter APRS.

Following your "PHASE-1" recommendation, I have modified my iGate config to
use the "Omni receive Only" symbol by changing my PBEACON string to:

PBEACON sendto=IG delay=0:30 every=10:00 symbol=O& comment="Raspberry Pi
iGate on 145.825 -- Omni Antenna, RX-Only" lat=37^46.72N long=77^36.58W

... and the result shows up graphically on aprs.fi as shown on this screen


... so, other than the fact that my status text message is completely
redundant to the "O" symbol AND is also redundant to the implied RX
frequency of 145.825, have I followed the spirit of the PHASE-1
recommendation to display a symbol icon that is a better indication of my
iGate's configuration?

-Scott, K4KDR


On Mon, Aug 7, 2017 at 2:11 PM, Robert Bruninga <bruninga at usna.edu> wrote:

> I think we should better organize our automated automatic APRS satellite
>  ground stations. We found about 330 unique IGATES feeding the APRS-IS and
> the two APRS satellite networks:
> http://pcsat.findu.com  and http://ariss.net
> For decades a hot topic at SmalSat conferences has been remote ground
> station networks.  Some costing $100,000 or more but with only a half dozen
> other stations that seem to always be just one more software, and one more
> receiver upgrade to actualy be operating.
> Meantime, APRS has had global ground stations by the hundreds. They all
> work fine for APRS donwlinks on 145.825.
> I am not really interested (for now) in diluting this always-listening
> network by spinnning off stations that can be remotely tuned to go listend
> to the other hundreds of small sats and their UHF downlinks which require
> tracking AND Doppler tuning,  For now, I'd rather encourage more AMSATS to
> use our network and provide more APRS transponders!
> In addition, I'd like to at least see about making this ground station
> netwrok to be TWO_WAY just like APRS was designed, so that small satellite
> control operators with satellites on 145.825 can send APRS message back to
> their spacecraft for control anywhere anytime. The inherent protocol does
> this already (once a fground station has heard the satelite at least once
> on that pass).
> I do think this transmit path might need to be available only to valid
> control operators, though,,,
> Remember, with this many stations I have not encouraged AZ/EL active
> trackign but just omni receivers.  After seeign all the problems when Yaesu
> rotators are run full time, I do not think that is a strong idea for hams
> at home...  But maybe universities who have budgets to replace warn out
> equipment?
> So here are just some initial thoughts about this network we already have:
> PHASE 1:
> Lets choose a unique set of APRS symbols to clearly identify this network.
> In 2008 we expanded the APRS symbol set.  FOr example the \& gateway symbol
> has plenty of vacancies we can use for this purpose.  Here are the existing
> Gateway overlays:
> /& = HF Gateway  <= the original primary table definition
> I& = Igate Generic (please use more specific overlay)
> R& = Receive only IGate (do not send msgs back to RF)
> P& = PSKmail node
> T& = TX igate with path set to 1 hop only)
> W& = WIRES-X as opposed to W0 for WiresII
> 2& = TX igate with path set to 2 hops (not generally good idea)
> We could; define additional overlays for this Satellite ground
> station network:
> A& for Omni "AMSAT" ground station (2-way, 50W radio)
> L& for Omni "AMSAT" low power or other wise less than optimum sky view
> O& for Omni receive Only
> H& for HFSAT (that will be our next one in a few years)
> Y& for Yaggi oscar class (Gernerallyh tracks APRS sats of current interest)
> U& for UHF downlinks chanel (TBD)
> S& for Schools and University class (always on and can track on demand?)
> and can QSY when we figure out how we want to do this... (and can afford to
> wear out their stuff)
> V& for Various?  Since APRS has a FREUENCY SPEC already, we can assume that
> all stations using these symbols are on 145.825, UNLESS they include a
> different frequency in their STATUS text.  A V station might be VARIOUS and
> that indicates that it is auto tracking and auto tuning any satellite in
> view and is beaconing that frequency in its status each time it changes
> frequency.
> THen lets come up with some well defined way to categorize capablities so
> that it all fits in the station's STATUS packet in a consistent way.
> I know there are LOTS of ideas of all kinds of automated linked ground
> stations.  I am not trying to disrupt all those ideas, but simple clean up
> what I think is what APRS already has?
> Does this seem like a plan?
> Bob, WB4apr

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