[EAS] Remote RWT switching

[Dale Lamm]

Mike,

If I was in your situation and needed to transmit RWT's over a distant
transmitter (with the EAS unit at the distant site attached to your
monitoring input sources), I could first look for a way to control the
distant EAS unit using a remote control or side-channel signaling. If
that was not possible, I'd consider as you proposed and use in-band
signaling, probably DTMF since the decoders are so widely available.

If that was not possible because of cost constraints, then we need to
get creative...

You probably just replaced your EAS box. You probably have the old one
sitting on a shelf in the basement, unused.

Take it out of the basement, replace the lithium battery, make sure it's
in good order. Install it in your program line, between the console and
the AGC for the STL. Don't bother hooking up any monitoring inputs.
Reset the unit to factory default, clearing all the incoming-outgoing
filters except for the mandatory RWT-RMT-EAN filters. Set your call
letters and originator codes. Program the EAS unit to issue an RWT when
it senses a closure on two pins on the rear connector. Attach those two
wires to your automation's GPIO output and set up the automation to
force a closure when a special item appears in the traffic log.

Customary activations of EAS will cause the unit at the transmitter to
fire and relay the message. RWT's are instead originated from the
studio, using the old EAS unit. The new EAS unit will not even see the
header burst on the STL feed, because program line inputs are not
monitored. The pass-through allows the old EAS to live on as a backup
RWT generator. Be sure your call letters are set into the studio EAS
unit, same as at the transmitter's EAS unit. Be sure the clock on the
studio unit is maintained, just like you did all those years it was in
service before June 30.

You might even want to issue RMT's from the studio unit, and allow the
transmitter unit to handle EAN, TOR, etc alerts, since that's where the
monitored sources are attached.

So, your cost is minimal, assuming you can obtain an "obsolete" EAS
unit.

If you wanted to achieve a greater level of service to your community,
you could attach a NOAA receiver to the studio EAS unit and program in
all the customary weather-related alerts. That way, if the transmitter
EAS unit fails to act on a NOAA alert because the remote NOAA receiver
has failed, you'll be covered. Logging EAS activations would now involve
gathering info from two EAS units.

Now, let's say your studio is feeding not one, but several broadcast
transmitters, each with a different FCC callsign. I would propose that
the 8-character ID in the studio unit could be set to your company name
instead of an FCC assigned callsign. The point of the ID field is to
tell downstream stations where the alert was relayed from. I think that
stations monitoring your LP station(s) could figure out where the RWT
came from if they saw a company name in the ID field. Of course, this
might fly in the face of your SECC's recommendations. I can't
immediately locate any Part 11 rule which specifies the precise content
of the header's ID field.

Hopefully, this will stimulate discussion on uses for "obsolete" EAS
units. We have already made plans to re-deploy our old units in a way
that enhances our public service mission. I will start a new thread on
"uses for your old EAS unit" and encourage others to add their ideas. No
need to let that old model 1822 sit on a shelf in the basement.

Dale