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[aprssig] Satellite positions: FREQUENCY

Bill Vodall wa7nwp at gmail.com
Wed Oct 19 16:15:26 UTC 2011


On Tue, Oct 18, 2011 at 6:06 PM, Lynn  wrote:
> The DIGI_NED model only works when directly connected to local RF.

Ah but that's what this is all about...

> And that
> requires local operators to do the configuration and maintenance to keep it going.

Building infrastructure does take a little effort and it's generally worth it.

> I'm trying to offer a globally-accessible satellite information service.

It will be good and I'd be taking advantage of it today if it were
running.   There are a couple tweaks to the system I will be
suggesting...

>  I'm not trying to replace what DIGI_NED has accomplished at the local
> level, but provide something new and functional from a much broader
> perspective and service area.

This is very good but please keep in mind what happens at the local RF
level and build your system to complement that...


> There is no way in APRS for a central server to push information out to a
> local RF APRS network except by sending an APRS message directed to a
> station that was recently heard local to an IGate.

This is a real weak point in our APRS system.   That's another discussion.

>  And the only way to
> reliably know that is to design and implement a centralized query / response
> system.

Also the Igates can selectively do the 'igating...'   The Poll model
useful at some times but for an ongoing use I hope the objects will be
available continuously without polling..

>

Suggestions:

I would suggest that you set up a dedicated server alias to generate
the objects.   It could respond to the simple name queries like "iss"
but it could also respond to its own name.

Use a uniquely coded name for the objects generated.  'ISS' will be
used by the local servers so you could key all your objects with
something like 'is*'  - thus you would generate 'isISS'.  This would
also allow folks to gate the objects to RF based either on the name of
'is*' or on the alias of the server generating them.

What happens if the server goes down?   Will there be a hot spare at
some other location watching and ready to take up the load?

What happens it you get tired of this silly game and decide to go work
CW?   Will we lose the resource as has happened before?

>

Thanks again for all your energy and efforts here..   You've brought a
spark of new life to the system.

73
Bill - WA7NWP



>
> Lynn (D) - KJ4ERJ - Author of APRSISCE for Windows Mobile and Win32
>
> On 10/18/2011 7:41 PM, Bill Vodall wrote:
>>>
>>> I still believe that the best possible use is to query when you think
>>> you've
>>> got time to work the satellite.
>>
>> I have to come back to the DIGI_NED model.   One packet per bird every
>> 10 minutes with the next predicted AOS (or something) time.  Then when
>> it's in range, one packet a minute with current information.
>>
>> It's surprising how one finds the time to bounce a few packets through
>> a bird or listen to the channel when it just happens to be opportune.
>>
>> DIGI_NED has the poll feature.  Used it once to verify it works and
>> never went back.



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