acb at incident.com
Thu Jan 14 12:31:27 EST 2010
The question isn't whether CAP could be transmitted as modem tones over the program channel... obviously it could... but whether broadcasters could tolerate the length of the data bursts required. (Not sure they'd need to be quite as long as Richard suggests, but they'd certainly be a lot longer than the current SAME tones, at least on AM.)
Then again, CAP was created for the purpose of integrating multiple warning systems, not just for EAS, so it was never envisioned to rely on modem-driven audio channels. The need for a digital relay network is the price of the higher level of capability and interoperability that CAP provides. At present the easiest way to provide that data relay network is by using the commercial Internet, but that's not the only option. Nor are all parts of "the Internet" equal in terms of their reliability and security.
So again, speaking personally, I suspect that station-to-station alerting using the current SAME tones will be with us for some time, as will SAME transmissions over Weather Radio. In some areas there may be a rapid build-out of digital CAP infrastructure all the way down to the individual participating stations. In other places the translation from universal CAP to broadcast-specific SAME format may occur at the LP or even SP level for some period of time. As mentioned earlier, TV providers may have a more immediate desire to receive alerts in CAP format than mom-and-pop radio outlets.
Therefore, again speaking personally, I don't see a pressing need to change the on-air presentation of EAS over analog radio broadcasts. But I do think we need to start thinking very seriously about how best to present the richer and more targeted information available in CAP to audiences of next-generation digital broadcast transmissions.
On Jan 13, 2010, at 1/13/10 11:02 PM, Marlin Jackson wrote:
> We're the LP-1 in Spokane, WA. We have a CAP box connected to the internet. Presently we are receiving messages from Washington State via the box. It decodes the message and outputs audio with only the information needed to trip our system as audio from a radio link would. Any additional information if any is ignored. If anyone wants the additional information they would need to be connected to the internet with their own box programmed for what they want out.
> Is there plans for station to station CAP or is it only planed for distribution to the broadcaster? I believe the Washington State plan is to have a CAP box at each station or group if co-located. Every station with a box will get the message at the same time as the LP-1.
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