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[aprssig] Mic-E Issues

Curt, WE7U archer at eskimo.com
Wed Jul 16 17:10:35 UTC 2008


On Tue, 15 Jul 2008, Robert Bruninga wrote:

> All APRS formats are compatible.  They get converted to LAT/LONG
> and the same text on receipt.  I am leary of using the base-91
> compressed encoding because it had been used so rarely, and
> enough authors are no longer supporting their code, that I worry
> as to whether a base-91 encoded position will be properly
> received by all parties.

An entire chapter of the original APRS spec was devoted to Base-91,
_all_ of the OpenTracker/Tracker2 products support it, UI-View,
Xastir, plus most of the other APRS clients support it.  I'd expect
some backlash if you decide arbitrarily to cut it from the spec via
the latest addendum.

I've already seen "Items" and "compressed" objects/items come under
the knife (which I still disagree with).  Cutting pieces of a spec
because some clients didn't fully implement the spec or didn't
implement it properly isn't good.  For what it's worth Xastir still
supports these.

Some of us rather dislike Mic-E protocol.  A better alternative
exists in the form of Compressed (base-91) packets.  Cut more of the
good stuff out of the spec and there may be more of a push to start
using/developing OpenTrac protocol.


> And if one does not have full confidence that what he transmits
> will be received, then it's a little iffy to use it in my
> opinon.  For example, the older Kenwoods do not properly decode
> a "compressed-base-91 OBJECT".  SO no one should ever use
> base-91 compression for an object or 85% of the mobiles will not
> see it...

Because the spec wasn't fully implemented in the Kenwoods we
shouldn't use it.

To extend that quite a bit further:

*) Find bits of the spec that weren't implemented in some client or
    implemented incorrectly.
*) Decide not to use that piece of the spec.

Eventually there wouldn't be anything left of the spec to use.  If
_everybody_ can't use one of the bits, then _nobody_ should use it.
hi hi

-- 
Curt, WE7U.				archer at eskimo dot com
http://www.eskimo.com/~archer
   Lotto:  A tax on people who are bad at math. - unknown
Windows:  Microsoft's tax on computer illiterates. - WE7U.
The world DOES revolve around me:  I picked the coordinate system!"




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