[EAS] Mindless Murmurings about Munged Messages

[ray at electronicstheory.com]

David, I saw the same audio problem, and also requested that they increase the
time - but this isn't what I'm talking about.

I am looking at the actual decoded stream and finding this.

To my untrained eye, this looks like it didn't receive (or at least it couldn't
decode) the whole message:

"An EAS message (event id=1284) could not be unambiguously decoded from channel
'L2' at 'Tue Aug  7 18:50:17 2012' on Decoder 'WXYZ'.

 Error information is available:.
Error='Invalid header decoded.'
Header.1='ZC?WP?ZC-J1'
Header.2='ZKZ?i'
Byte_Errors='12'
Bit_Errors='20'
Error_Mask.1='ef f6 da f3 a2 97 00 00 fb ff ff '
Header_Seq.1=' Z  C  ?  W  P  ?  Z  C  -  J  1  '
Dcoded_Dif.1='      09       12                 '
Error_Mask.2='33 17 fd fe 7f '
Header_Seq.2=' Z  K  Z  ?  i  '
Dcoded_Dif.2=' R       a1     '?

On August 8, 2012 at 8:59 PM David Turnmire <eassbelist at cableone.net> wrote:

> On 8/8/2012 2:49 PM, ray at electronicstheory.com wrote:
> > ... I do NOT recall ever seeing what I am now seeing with the DASDECs.
> >
> > The DASDEC sometimes doesn't catch the whole message.  I'm fairly certain
> > that
> > this is due to atmospherics during storms.  When it gets a partial message -
> > it
> > logs it as a partial message.  I don't recall ever seeing that with the
> > other
> > systems.
> > ...
> Are you sure it is REALLY a partial message?  I came from a SAGE
> background when we switched to DASDECs.  And I ran into an oddity that
> may be what you are observing.  I don't have my DASDEC in front of me
> right now, so I'm going from memory.  As I recall, if you are on the
> Decoder menu and observing the log of alerts, the associated links play
> essentially only the voice part of the message.  But... if you go to the
> Setup=>Audio page and click on the "snap shot" links, you'll get a more
> complete recording, including any program audio leading into and out of
> the alert, the data tones, etc.
>
> Now here comes the oddity... when you click on the snapshot links, the
> recording may start in the middle of the alert... but if you are patient
> and play the recording to the end, you'll hear the beginning of the
> alert... later, at the end of the recording!.  Essentially what is
> happening is the DASDEC records a continuous loop of something like 3
> minute duration.  When the snapshot is triggered (typically be an
> alert), it essentially captures that loop as it exists at that time.
> But where the alert is within that loop is somewhat random.  Apparently
> doing it this way made it easier for the programmers... but more
> confusing and less convenient for the users. I put a request in for them
> to change that and they said they are considering it.
>
> Take a closer listen to what you have on your machines and see if this
> is what you are experiencing.  I have had mine in service since
> something like November and since I'm SECC chair, I tend to monitor more
> sources than the typical station (four CAP servers and four receivers).
> Plus we have a couple DASDECs at other locations in the state that I
> routinely login to to see what is happening in those markets.  I haven't
> run into the "partial message" issue, other than what is described above.
>
> Dave
>
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