[aprssig] Timestamp Questions

Bob Bruninga bruninga at usna.edu
Thu Jun 9 10:38:32 EDT 2011

> That is decidedly NOT what aprs101.pdf says on page 22:

> 092345z is 2345 hours zulu time on the 9th day of the month.
> 092345/ is 2345 hours local time on the 9th day of the month.
> 234517h is 23 hours 45 minutes and 17 seconds zulu.

> Are you going by memory Bob, or did you actually check somewhere for that

Got me there.  I was going by memory, because it was my intent in
introducing the "h" format so that small devices could be built that did not
have real-time clocks or calendars.

But given that the spec says it is in zulu, then that is great!  That is
better of course.

Bob, Wb4APR

Lynn (D) - KJ4ERJ - Author of APRSISCE for Windows Mobile and Win32

On 6/9/2011 9:22 AM, Bob Bruninga wrote: 
If it is “h” it is assumed to be local.
If it is “z” it is UTC (zulu).
Bob, Wb4APR
From: aprssig-bounces at tapr.org [mailto:aprssig-bounces at tapr.org] On Behalf
Of Rud Merriam
Sent: Wednesday, June 08, 2011 2:17 AM
To: TAPR APRS Mailing List
Subject: [aprssig] Timestamp Questions
Is an 'h' format timestamp assumed to be local or UTC?

Does APRS-IS send out 'h' timestamps as local, UTC, or as received from

If I am doing a HUD display for messages (or other stuff in the future) do I
care about the timestamp?  

- 73 - 
Rud Merriam K5RUD
Emergency Coordinator
Montgomery County ARES® 
Mystic Lake Software

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