[amsat-bb] A suggestion for Experimenter's Wednesdays on AO-91

Mac A. Cody maccody at att.net
Fri Dec 15 15:28:31 UTC 2017

JoAnne and EMike,

That is why I suggested as an experiment the use of NBEMS in my original 

"The messages could be sent digitally via, say, Narrow Band Emergency
Messaging System (NBEMS) to improve reliability of transcription."

Yes, voice would be slow and inaccurate.  Using digital data would send more
information quicker.  NBEMS can be use send various ICS forms, weather 
and ARRL Radiograms.  The data streams you suggest are already supported
through NBEMS.    NBEMS is designed precisely for this type of application.

NBEMS can work on SSB as well as FM modes.  Given that there are already a
sizable number of amateur satellites orbiting the earth, and more 
coming, there
would be many opportunities to pass traffic over LEO satellites. The 
birds would offer multiple channels for this activity.  I'm sure, 
though, that there
will be those that shudder over the thought of multiple data streams 
being passed
over the linear birds at one time.   Data transmissions would have to be 



On 12/15/2017 08:40 AM, JoAnne K9JKM wrote:
> EMike mentioned:
>> It seems to me that the limiting factor for using LEO satellites as an
>> Emergency Response of any scale, would the short amount of time of a given
>> pass and the limited number of usable passes a day over an area needing the
>> response.
> I agree, a verbal status report or request for assistance for an island-wide or city-wide disaster (think Puerto Rico and Houston) likely would not fit into the time for a LEO pass of a single satellite.
> But, us ingenious ham radio operator types perhaps have the basis of sending compressed data which conveys a lot of information. Packed into the bytes of telemetry messages we find out about voltage, current, solar cells, temperature, etc. We use a predefined interface document to decode the string of bytes.
> How about using a predefined disaster status data stream that all shelters (like scattered around an entire island) to encode 1) head count of staff 2) head count of victims 3) electrical power 4)drinking water 5) more supplies needed 6) need critical assistance. This way EOC staff could develop and maintain a system-wide status. Coordinating supplies or critical messages may also need better paths to complete than 10 minutes of satellite time.
> We fill data warehouses with telemetry bytes as ground stations around the world receive those defined telemetry streams and forward them. Conversely, if multiple LEO satellites support a disaster-status protocol then EOC staff could receive more frequent updates (having to tune and track a different satellite though). In this case the EOC uses multiple satellites vs. one data warehouse with multiple users.
> We'd need future cubesat missions capable of supporting a disaster telemetry stream. If we try something like this now it likely could see proof of concept with a single cubesat.
> Hoping someday we'll replace this cubesat approach with the AMSAT Phase 4 groundstation. That will be like having a wireless phone line between an EOC and every shelter.
> --
> 73 de JoAnne K9JKM
> k9jkm at amsat.org
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