[Rfu-barnraising] (fwd) (fwd) the EAS question

[Andy Gunn]

hey all, i sent out these questions last week, but haven't heard anything back about it.  these questions just need some thought, so let us know!
thanks,
-a


----- Forwarded message from Andy Gunn <andy at prometheusradio.org> -----

From: Andy Gunn <andy at prometheusradio.org>
Subject: the EAS question
To: leti <leti at lists.prometheusradio.org>,
	rfu barnraising <rfu-barnraising at lists.chambana.net>
Date: Fri, 28 Oct 2005 19:09:14 -0700
Organization: Prometheus Radio Project

hey all, i have been thinking a little bit about how the emergency alert system unit will be set up during the barnraising.  if i recall - you have a trilithic EASy decoder - which is great.  those have two built in radio receivers, and a built in audio interrupt switch.  the only things it doesn't come with is a line printer (think of an old dot-matrix printer, with continuous feed paper), and fm and am antennas.

the printer is technically optional - if you have a computer in close proximity to the eas unit, and it has a serial port - you are all set.  just use the software they include, download the logs and print them out on any printer.  i would recommend getting a dot matrix printer (or two) at a surplus place or garage sale - they are pretty much free these days.  use the serial / computer thing as a secondary backup or something.  the fcc will want those eas logs when (and if) they inspect, so good to have at least one copy hangin out.

the important thing is the receive antennas, and a place to hang them.  for the fm receive antenna, any big log-periodic antenna that you can get at radioshack for outdoor use will work well.  think big, crazy lookin rooftop antennas.  for an am antenna (if one of your local primary stations is an am station), a really long wire, a big loop or ferrite rod/bar antenna will work.  getting some receive antennas shouldn't be a big expensive deal, i hope.  maybe people with old rooftop receive antennas they don't use anymore would be willing to take them down and donate them.

the harder part is running cabling from wherever the receive antennas are located.  if the EAS unit is in the studio, then 75ohm coaxial cable or 300ohm ladder line will need to be run down from the roof or from some point outside, where ever the receive antennas are located.  the cabling should be cheap, if no one has extra they can donate or scrounge up.  start thinking about how the cabling can be run through or on the outside of the building.  if the EAS unit is in the rack with the transmitter the cable run could be shorter, and go along with the coax to the tower, where the antennas can be hung.

the better location for the EAS unit might be the rack upstairs with the transmitter and audio processor.  the cabling for the receive antennas is shorter, and it can be placed on full auto interrupt, so if there is ever a time when a dj is not there and the station is running on automation, then the EAS will still trigger if it recieves an alert or test.

the problem with having the EAS upstairs with the transmitter is that no one is watching it, so if there is a problem, it would only be noticed whenever someone went to check on it.  that would need to be a few times a day.  the weekly test does have to be triggered within a short amount of time (within an hour), so it would be good if it were in the studio where someone would be watching it.  it isn't the end of the world if a test gets messed up, so long as the problem is corrected for the next one.

some things to think about!
-a

----- End forwarded message -----


--

--------------------------------------------------
|  Andy Gunn - Technical and Training Organizer  |
| Prometheus Radio Project - prometheusradio.org |
|    andy at prometheusradio.org   215-727-9620     |
--------------------------------------------------

---------------------------------------------------------------------
| Come to our next radio station Barnraising and community wireless |
| congregation!  November 11 to 13, Champaign-Urbana, Illinois.     |
| Prometheus Radio Project * UC Independent Media Center * WRFU-LP  |
| Check http://www.prometheusradio.org/urbana/ for more details!    |
---------------------------------------------------------------------