[EAS] Interesting zombie artifact (I think)

[Gregory Muir]

Thank you, Harold.
 
It was an oversight on my part not thinking about a possible replay of the event via a news broadcast or whatever that was being sent by a monitored source.  That would be logical.  Additional investigation after I wrote my post found that this message was also received by others as well.  In addition,I just received an email from the "original zombie" station engineer stating that he has received a few similar reports form other stations around the United States so this bears more proof of your explanation.
 
It is obvious that if the event message is pre-recorded and played back at some extended time or date outside of the event time window included in the message header, it will most likely be excluded by the receiving ENDEC.  I have helped other engineers with this problem when their units weren't automatically resetting their RT clocks to the proper time at a ST/DST changeover and they were wondering as to why the messages were not being relayed.
 
Thanks again!
 
Greg
 
Original message:
 
From: Harold Price
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Greg,

>I've tracked at least one of this type of report
back to the source, I've seen many others that are similar.

>If the alert shows up in the log as "expired",
and the dates in the displayed message are for a
prior day, your device has heard a recording of
the actual event, played back as part of news,
commentary, or "funny things this week" broadcast
on the station you are monitoring.  Check with
your monitor source, see what they were playing
at 02/12/13 20:23:17 your local time.  Remind them that part CFR 47 11.45 says:

>"No person may transmit or cause to transmit the
EAS codes or Attention Signal, or a recording or
simulation thereof, in any circumstance other
than in an actual National, State or Local Area
emergency or authorized test of the EAS.
Broadcast station licensees should also refer to ?73.1217 of this chapter."

>73.1217 refers to broadcast hoaxes.

>Sometimes this is part of a news package that
comes from upstream, and as a practical matter,
there is little you can do.  Sometimes, it comes
from local staff, playing something from You
Tube.  The latter is something that can be
locally controlled, and should be part of local training.

>Background:

>Sometimes, especially with legacy equipment,
clocks will get out of sync at the sending and
receiving station, so that the time will be out
of the capture range of the receiver, which
starts at the timestamp in the EAS message, and
runs to timestamp+duration.  The ENDEC reports
this as either "behind", if it appears to be a
few days ago, or "ahead" if it appears to be in
the future - other vendors have other nomenclature.

>Sometimes, with newer equipment, either the
sender or receiver will have their UTC offset
entered incorrectly, so that the timestamp in the
message is incorrect, or the timestamp in the
receiver is interpreted incorrectly.

>In these two cases, the call sign in the EAS
message will be what you expect it to be - the
call sign (or group id) of your monitor assignment.

>In the case where the call sign is something
else, or the time is off by a day or more, you
may be hearing a recording of an alert, as I
suspect is the case for Greg's log.

>An ahead or behind log entry (or your vendors
equivalent), means you should do a little
investigation to see just what is going on.  For
properly configured devices, the ahead or behind messages won't get on the air.

>[For completeness, in a message that is already
too long, there are other permutations - you will
see the call sign you expect if your monitor
assignment is playing a "best of" recording that
includes a copy of an EAS message they
sent.  This will happen if the ENDEC is in-line
before the recorder.  You will also see the call
sign you expect if the relay point held the
message just long enough to be expired when you
receive it.  Both of these cases occur in the wild from time to time.]

Harold

At 01:47 AM 2/14/2013, Gregory Muir wrote:
>I am throwing this out there as a real curiosity item to the group.
>
>The below event was logged on a Sage machine
>owned by a radio station that is located in the
>same town that the original Montana "zombie"
>television station is located.  It never made it
>to air due to several strange characteristics to it which I will explain.
>
<Remainder snipped>