Pat,
Even as late as 1969, our college station had an official EBS monitor. It
was a rack-mounted AM receiver which was supposed to be tuned to one of the
designated EBS stations. So the story goes, when the EBS alert sequence was
broadcast, relays in the receiver were tripped and the monitor speaker would
come on and broadcast instructions from the EBS station. We thought the
whole thing was pretty funny since there was no antenna hooked to the
receiver, and even if there had been, our campus was too far away from any
local stations for the receiver to be of any use. But we all felt better
knowing that our 10-watt FM and closed-circuit AM station was in voluntary
compliance with the FCC rules regarding EBS. Well, maybe not full
compliance, but close enough.
Steve
----- Original Message -----
From: "Pat Byrne" <[log in to unmask]>
To: <[log in to unmask]>
Sent: Tuesday, November 15, 2011 18:49
Subject: Re: A Bit of Radio History
>I think that the grand discovery was made that A M radio wouldn't
> cause the end of the world!! Technology got ahead of CONELRAD pretty
> quickly I think.
> For a lot of years after I got my license we were supposed to monitor
> broadcast radio and shut down if they did. I just let a very quiet a
> m radio run in the shack. Now I couldn't hear it!!!
> Pat, K9JAU At 11:50 AM 11/15/2011, you wrote:
>>There must have been some significant issues with that system because it
>>was
>>abandoned after a fairly short period. Interestingly enough, AM radios
>>made
>>at that time actually had markings for the two frequencies 640 and 1240.
>>
>>Steve
>>
>>
>>----- Original Message -----
>>From: "Martin McCormick" <[log in to unmask]>
>>To: <[log in to unmask]>
>>Sent: Monday, November 14, 2011 12:32
>>Subject: Re: A Bit of Radio History
>>
>>
>> > I do remember the CONELRAD tests.
>> >
>> > Radio and television stations would broadcast an
>> > introductory message as to what was about to happen. The carrier
>> > would go down for 15 seconds. Then, it would come back up for
>> > another 15 seconds. It was down for yet another 15 seconds and
>> > when it came back up, there was a 1 KHZ tone for maybe another
>> > 15 seconds. CONELRAD receivers had to detect the two drops in
>> > carrier plus the tone and that initiated the CONELRAD condition.
>> >
>> > My father was a science teacher at a school in Tulsa,
>> > Oklahoma at the time and had gone in to the teachers' lounge or
>> > maybe the school office for something and turned on the radio.
>> > He first thought the radio was broken because there were only
>> > two signals on the air. Then, he was reminded of the test which
>> > went for half an hour or so and then all other stations came
>> > back on and things were normal.
>> >
>> > I think the test was done every year for a while. I
>> > don't remember the first test, but the one in 1957 or 1958
>> > featured a talk by our state's governor at the time.
>> >
>> > I bet the station engineers loved this test if their
>> > station was one of the CONELRAD stations because they had to run
>> > all this stuff that you couldn't test any other time and it had
>> > to work perfectly this one day and, of course, be ready to
>> > switch in on a moment's notice.
>> >
>> > Tulsa had a 50,000-watt station KVOO at 1170 which was
>> > one of the CONELRAD stations so they had to electrically chop
>> > off part of their antenna to tune it up on 1240. I am sure this
>> > was accomplished by large contactors which are just huge relays,
>> > but still, when else could you make sure it worked?
>> >
>> > The other 50,000-watt station in Tulsa was KRMG at 740.
>> > I have no idea, for sure if they were the 640 CONELRAD station,
>> > but they would have had to add some electronic length to their
>> > masts to reach 640.
>> >
>> > It did work, however, so it just shows you what people
>> > do when they need to.
>> >
>> > Something else you might find interesting during those
>> > days was a plan to use AM broadcast transmitters as data links
>> > for RTTY and Morse.
>> >
>> > There was an article in "QST" several years ago about
>> > WSM 650 in Nashville TN. They actually had a FSK encoder on
>> > their 50-KW transmitter which shifted the carrier maybe 50 HZ
>> > and would have let them send RTTY to suitable decoders. An
>> > average citizen listening to WSM would have noticed nothing
>> > unusual. The article described the test transmission as a loop
>> > sending the call letters and the word "test."
>> >
>> > Lloyd Rasmussen writes:
>> >> I don't remember hearing any of those celebrity PSA's, but they aren't
>> >> very
>> >> different from what FEMA tells us today at ready.gov or other
>> >> websites.
>> >
>
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