[EAS] New EAS handbook

[Sean Donelan]

On Wed, 26 Jul 2017, Tim Stoffel wrote:
> That and the duck farts.
>
> As far as 8 seconds go, that, I think is a reasonable compromise. It does take humans a few seconds to 'shift gears' as it were, or at least it takes me a few seconds.

Since marketers keep using a simulation of EAS sounds in advertisements, 
that probably a good indicator those soudns get peoples' attention.

The data bursts (duck farts) is approximately 10 seconds plus 8 seconds of 
attention tone. Depending on how many FIPS location codes are in the 
header, thats about 15-20 seconds before the public hears the first word 
of the warning message.  And there is usually a preamble in the message 
"The National Weather Service has issued a...."  Compared to a 15 or 30 
second ad spot, EAS messages take a long time to get to the point.

CMAS/WEA alert signal is one long tone of two (2) seconds, followed by two 
short tones of one (1) second each, with a half (0.5) second interval 
between the tones; repeated twice.  The total length of the WEA special 
alert tone is about 12.5 seconds. The WEA message appears on the mobile 
phone at the beginning of the special alert tone.

In the next-gen EAS, there are a lot of different parts to think about.

The public thinks of the in-band signalling data burst as the "warning 
signal" because that's the first thing they hear.  The attention signal is 
the noise that annoys the cats in the house. 20 seconds later, when the 
emergency message finally starts, the public has already changed the 
channel because 99 out of 100 times, that sound is only a test.