[sbe-eas] National WEA and EAS test performance

[JACOB, KD9LWR]

Great info! I've recently been thinking about this... By the time an 
emergency gets recognized, messages prepared and sent, etc, how much 
time does a person have left?

On 10 Nov 2021 17:15, Sean Donelan wrote:
> FCC surveyed major cellular carriers about the performance of the 
> national Wireless Emergency Alert system.  The lawyers at the FCC and 
> lawyers at the carriers have been exchanging letters, talking past each 
> other. I don’t know if they are intentionally misunderstanding each other.
> 
> WEA Part 10 and EAS Part 11 do not have any specific performance 
> requirements. Just vague terms like immediately. Computer clocks at 
> alert originators, FEMA IPAWS, cellular and broadcasters are not tightly 
> synchronized.  While GPS and NTP can keep computer clocks with 
> milliseconds, EAS and WEA timestamps usually vary 5 to 10 seconds. 
> Recent changes to EAS allows up to 15 minutes clock skew for message 
> validation windows.
> 
> So...
> 
> What was the end-to-end latency of the national WEA test?
> 
> What was the end-to-end latency of the national EAS test?
> 
> For an engineer, it’s a difficult question to answer precisely.  Roughly 
> (95% confidence), it takes about 1 to 2 minutes for a national EAS or 
> WEA alert end-to-end from FEMA to reach the public. Minimum: 36 seconds, 
> Maximum: 30 minutes (never). Including encoding/decoding latency, but 
> not including delays in FEMA systems or alert origination.

-- 
v/r
Signed/
Jacob Edwards Wiese KD9LWR/
Cell 219 221 0486/
Hamshack Hotline 12606//
CoCoRaHS/IN-LP-65//

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