[aprssig] APRS SPEC: Wind Speed confusion

Andrew Pavlin spam8mybrain at yahoo.com
Fri Oct 14 11:06:01 CDT 2016

Who's using the Course and Speed extension? Anyone reporting the position of a mobile station without using Mic-E, and anyone reporting the position of a moving Object/Item. Both of those cases would probably include the course and speed to get more accurate dead-reckoning of the moving station/object's position between reports.
Now, which stations actually do that is another story. Very few Objects/Items are moving targets, and most mobiles use the Mic-E format. Is my YAAC software the only one that gives the option of reporting mobiles with that extension?
Andrew, KA2DDOauthor of YAAC

      From: Kenneth Finnegan <kennethfinnegan2007 at gmail.com>
 To: Greg Trasuk <trasukg at trasuk.com> 
Cc: TAPR APRS Mailing List <aprssig at tapr.org>
 Sent: Friday, October 14, 2016 11:46 AM
 Subject: Re: [aprssig] APRS SPEC: Wind Speed confusion
On Fri, Oct 14, 2016 at 8:33 AM, Greg Trasuk <trasukg at trasuk.com> wrote:

Unless there’s a compelling reason otherwise, I’d standardize on knots,

I'd say the compelling reason is that the weather data packet format on page 64 of APRS 1.0.1 says mph, so it's likely that the majority of implementations working off the spec already use mph. 
Knots is currently used for the Wind Direction and Wind Speed data extension and the storm data report. I think the distinction of where we use MPH vs Knots is pretty clear, but accepting Bob's premise: * We can't change the Wind Direction/Speed extension to mph since it's indistinguishable from the Course and Speed extension. Where is this extension even used? I'd vote for deprecating it.* I'd be ok changing the Storm Data report to MPH, but I live in California so my indifference is high on this one.
Kenneth Finnegan

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