[aprssig] Voice Repeater Frequency Objects

Joel Maslak jmaslak-aprs at antelope.net
Thu Sep 18 20:09:20 EDT 2008


On Sep 18, 2008, at 10:15 AM, Robert Bruninga wrote:

> So the only thing we can guarantee that a recepient will *see*
> is what is in the first bytes with less reliability further out.
> This places a priority on the left-justification of priority
> data in all position and object comment fields.


I know a bit about software engineering, having studied it and worked  
professionally in the field.  One key principle is to separate  
presentation from data.  Most APRS clients do this (including DOS  
APRS, AFAIK).

For instance, position formats shop up one way, even though they  
might be MIC-E, Compressed, NEMA, or whatever else is allowed (don't  
have the spec in front of me) - the display shouldn't make someone  
manually decode these things, unless of course they are wanting to  
(and then it *should* allow them).  Nobody at the EOC during a  
disaster is going to want to see these packets differently just  
because the format was different.  They want to see the area where  
the flooding is reported.

That's separating presentation from data - either can change without  
affecting the other.  We could add another position format and that  
shouldn't require users (with updated software) to know how to  
manually parse it.

I agree with others who have said that the /A= shouldn't be displayed  
as part of the comment - it's part of the three-dimensional spacial  
position of an object/station, and it should be treated the same way  
- displayed where LAT/LON is displayed, not displayed where it isn't,  
and *possibly* selectable to be displayed on an icon-based system  
with icons on a map.  I can't imagine it would be impossible to make  
the Kenwood do that, at least the 710 - maybe Kenwood could release  
the firmware source code and they'll get free labor to do it.  ;)

Also, how does the 710 report altitude to RF?  I'm simply curious.

> If an application or any tracker software wants to maintain the
> flexibilty designed into the spec to allow the user to choose
> the importance (display priority) of his data elemets, it should
> give the user the option of where to put that data and not
> arbitrarily force the user into only one location and hence
> violate the intentions of the spec.


Does DOSAPRS really make someone look at comment strings to see  
altitude?




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