On 8 Sep 2004 15:34:27 -0400, (Scott Dorsey) wrote:

In article ,
Pete & Renee Davis wrote:
Can anyone tell me when the civil defense frequencies started being
marked on radio AM dials, and when the markings were discontinued? I
have come across several radio that have them. One was a Motorola add-on
car tube radio (in a stylish shade of turquoise) but no date on the
paperwork, another was a Zenith AM/FM whose paper labels had worn off,
and the other is Bendix Navigator 420 that was listed in catalogs for
1965 (Thanks Walt!).

They were not really civil defense frequencies, they were part of the CONELRAD
system. Do a web search on CONELRAD.

I think it might be reasonable to call them civil defense
frequencies. The "Control" part of the name, as I recall, consisted of
a.) all normal broadcasts were to cease and b.) the broadcasts on the
designated frequencies were arranged to switch among various
transmitters at short intervals. In effect, "spread location",
analogous in a vague way to "spread spectrum".The idea was to have
radio silence, except for the designated stations which each
transmitted in rotating bursts so that enemy aircraft or missiles
could not use a continuously transmitting station as a navigational
beacon.

At least that was the way it was described at the time.



As far as I know, the CONELRAD system stuck around until the beginning of EBS.
--scott


Just curious -- what's the ststus of EBS? I don't recall
hearing any of their tests in quite some time. IIRC, about three to
five years back, there was a dustup over an alert that was sent out as
if live -- no "This is a drill" wrapper was sent with it. When it got
to the radio stations, apparently almost all the GMs (or whoever had
the authority) said, "Naah, this is bogus -- we're not putting this on
the air."

In article ,
wrote:
Just curious -- what's the ststus of EBS? I don't recall
hearing any of their tests in quite some time. IIRC, about three to
five years back, there was a dustup over an alert that was sent out as
if live -- no "This is a drill" wrapper was sent with it. When it got
to the radio stations, apparently almost all the GMs (or whoever had
the authority) said, "Naah, this is bogus -- we're not putting this on
the air."

EBS is gone and has been replaced with the EAS system, which is supposedly
more suited to local disaster events and less for national alerts. It uses
FSK digital data keys rather than the single tone pair for keying. Frankly
it hasn't shown itself to be any real improvement if you ask me.
--scott


--
"C'est un Nagra. C'est suisse, et tres, tres precis."