[EAS] New EAS handbook

[Sean Donelan]

On Tue, 25 Jul 2017, Harold Price wrote:
> In the R&O, the commission removed some portions of Part 11 regarding the attention signal, but left the "8 to 25 seconds" mention in 11.31(c).

I assume it was for backwards compatibility since all EAS equipment 
wouldn't change instantly. Some encoders could still transmit longer 
attention signals, while decoders could accept shorter attention 
signals.

In practical terms, modern EAS equipment seems to tolorate receiving an 
attention signal between about 5 seconds and 30 seconds. Sometimes EAS
encoders are misconfigured.  A station in Washington, DC regularly 
transmits an abbreviated 6 (six) second attention signal (probably a 
configuration typo).

Since each EAS encorder generates a new attention signal while relaying 
an EAS message, even if you receive an EAS message with a long 25 second 
or short 6 second attention signal, your encoder will relay the message 
with a new 8 second attention signal.