[aprssig] APRS Object & Weather format

Andrew AB9FX ab9fx at aprs.pl
Sun Oct 24 17:13:52 EDT 2021

I think, a little detail is missing in the packet without position – that’s temperature. There is a need in the APRS standard to have a temperature field, at least t…


Andrew AB9FX



From: aprssig <aprssig-bounces at lists.tapr.org> On Behalf Of John Gorkos
Sent: Saturday, October 23, 2021 15:11
To: aprssig at lists.tapr.org
Subject: Re: [aprssig] APRS Object & Weather format


APRS Spec 1.01: 29 AUG 2000, bottom of page 65 (curse the editor that didn't put Table #s), "Complete Weather Format -- With Lat/Long position, No Timestamp" indicates that it should be valid.  HOWEVER, on the previous page, under the "Positionless Weather Data" heading, you'll see:
"NOTE:  The weather report must include at least the MDHM date/timestamp, wind direction, wind speed, gust and temperature..."

Ambiguity aside (I think a "Positionless Weather Report" requires the timestamp), it is valid to have a weather report without timestamp.  Just assume time=now().

John Gorkos

On 10/23/21 10:48 AM, Matthew Adair wrote:

I've been going over the APRS 101 specification and teasing it apart using Heikki's excellent Ham::APRS::FAP library.

Page 66 of the APRS101 document gives two example weather report formats as objects:

# Complete Weather Report Format — with Object and Lat/Long position

;BRENDA   *4903.50N/07201.75W_220/004g005t077r000p000P000h50b09900wRSW

;BRENDA   *092345z4903.50N/07201.75W_220/004g005b0990


The second object parses correctly. The first one does not.


>From what I can figure out, the reason is because the first object doesn't have a valid time stamp. The 101 spec seems to indicate that Objects require a time stamp. So, is the first object truly invalid, or is a weather object without a timestamp a valid exception?


- Matt, N8SHA

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