[aprssig] Is floating point telemetry allowed in APRS?

Matti Aarnio oh2mqk at sral.fi
Thu Mar 28 11:10:09 EDT 2013

On Wed, Mar 27, 2013 at 04:09:12PM -0400, Steve Dimse wrote:
> The spec is not fluid that way. If it says telemetry should look like 

The spec isn't fluid in many ways.  If you start to take a strict view
of what is carried in APRS-IS is only what aprs-1.01.pdf says, then most
of BoB's "errata" and "update" documents become irrelevant too -- and
frankly the whole APRS becomes an obsolete dinosaur starting with
prohibiting use of any characters outside ASCII.
(Tell that to Japanese, Greek, European in general...)

Telemetry is just one small example of things codifying what one particular
ancient microprocessor was capable of doing.  Strictly speaking it prohibits
reporting 10 or 12 or 16 bit ADC values, which has never stopped anybody from
doing it anyway.

If receiver's display routines are converting integers to rational numbers
for displaying, or plotting, what would prevent from from parsing a rational
number to begin with?

Very long ago I was doing something where we considered for a moment about
using APRS for telemetry.  We needed something like 20 ADC data channels,
50 booleans...

73 de Matti, OH2MQK

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