[amsat-bb] Re: APRS on Bernuda and Atlantic

Lynn W. Deffenbaugh (Mr) ldeffenb at homeside.to
Mon Dec 19 12:58:24 PST 2011

On 12/19/2011 3:30 PM, Howie DeFelice wrote:
> 1. It provides a standardized method of formatting and transporting the science data

Well, APRS's defined telemetry only supports 5 values ranging from 0 
through 255, but most client implementations support 0 through 999.  And 
there's also 8 on/off bits to go with it.  Maybe not enough for some of 
the science, but they could always transmit their own packet format(s) 
under the "experimental" data type.

> 2. Allows the science data to be automatically forwarded to a collection server allowing greater access to the raw data

Yep, they could just tap into APRS-IS and receive all of their own 
packets.  An no one would have to install any specific software to be 
receiving for them, only if they were interested in the content of any 
experimental type packets.

> 3. Every APRS igate around the world becomes a 24x7 collection node

Well, at least every APRS SatGate.  IGates are still country and/or 
locale specific on what frequency they're listening to, and I really 
don't think you meant to have the satellites competing with the local 
APRS traffic on a shared channel.

4.  And with each satellite having it's own ID in addition to 
(hopefully) ARISS as an alias, one could play with 
satellite-to-satellite digipeating and hop extreme distances with 
multiple satellite links.  The satellites themselves could do this if 
they were aware of their own orbital location.  When centered over vast 
water bodies and well out of footprint range of possible ground 
stations, they could even add ARISS to their own path to use 
brother/sister satellites to maybe bounce through to get to a ground 
receiving station.

> We in turn get a worldwide messaging tool. Imagine being able to notify the whole world at once that you just came up on SO-50 in that really rare grid :)

Make that a world-wide RF messaging tool.   We already have world-wide 
APRS messaging via the APRS-IS if you want to use it that way.  There's 
automated world-wide high altitude balloon launch notification groups, 
ISS activity notification groups, and APRSSATS notification groups.  No 
reason you couldn't create an SO50 ANSRVR notification group if you 
could interest enough satellite operators to monitor it for notifications.

The one requirement that this introduces for the CubeSats, however, is 
an APRS-receiving TNC and control logic.  Right now, I can imagine, many 
of the CubeSats may be deaf transmitters...

Lynn (D) - KJ4ERJ - Author of APRSISCE for Windows Mobile and Win32

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