Before EAS and EBS there was the Conelrad System. I only recall one complete test of the system in the early 60s. Here in central Kentucky the test broadcast on 640 Khz came through strong on my small transistor radio. The 1240 signal faded from strong to weak but audible. As I recall I was thirteen at the time. Do any of you remember where the Conelrad transmitters, that served Kentucky were located and the power output of the transmitters? I have been told that the emergency studio was located in a below-ground bunker at the White House with auxiliary studio equipment in the bunker at White Sulfur Springs West Virginia.
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Conelrad System Question
- Thread starter Nostatic1
- Start date
IIRC the old system was to have "selected" stations that stayed on either 1240 or 640(?) Some of the old radios (late 1950's or early 1960's) had the little "triangle" that we were suppose to tune to during WW 3. Thank God this was never used!! I worked at KIUL Garden City 1240 AM during the late 1980's and they still had an extra working basement studio. The stations that stayed during WW3 were on only two channels so the Russians could not radio directional finders. (That is one of the reasons radio stations did legal ID's. Aircraft use to have directional tuners that a pilot (or navagator way back) would tune an couple of AM stations (usually a clear channel station WSB, WGN. WSM etc.not the company!!) and vector their location. There was no GPS then. Stations that were selected to stay on were to have an engineer "tune" the station to one of the frequencies if they were not normally 1240 or 640. I guess the stations would have a extra crystal. The old tube transmitter which were electromagnetic RF pulse / surge resistant could stand a "missed tuned" antenna. KUIL still had an old spare tube transmitter when I was there. I am not sure of the national "master" control studio. I bet there were a couple. Air force One, was and is a suspect.
Nostatic1 said:
Part of the point of Conelrad was to ensure the Soviets didn't know where the transmitters were located(grin)!
Conelrad used regular AM stations. They were expected to switch to either 640 or 1240 and trade between sites in a seemingly random pattern. The idea was to cause direction-finders in Soviet bombers to keep flipping directions, to make it more difficult to get a reliable bearing.
My understanding is that they tried to switch stations to the nearest of the two frequencies. So I think you could probably assume the operations on 640 would have used WHAS, WAKY, (790) WTMT (620), and WKYW (900); operations on 1240 would have used WINN (1240), WKLO (1080), and WLOU (1350). That's just a guess though.
I think they took as much transmitter power as they could get. You couldn't fully tune a transmitter to a new frequency that quickly; the tower-matching networks wouldn't be right on the Conelrad channel; and the transmitter would be less efficient, so you'd have to back off the power to keep things from burning out. I suspect they really didn't *know* how much power they were using.
I suppose it all came to an end when they realized Soviet bomber pilots could read maps.........
Check this out: http://www.conelrad.com/index.php
w9wi said:
Actually, it was because ICBM's made the concept of frequency control obsolete.
As my user-name shows, I'm not from Kentucky, but am close enough to the Blue Grass State to listen to and to know about the radio stations there. In addition, I also attened college in the Commonwealth for two years.
With regards to Conelrad, I remember the test alert of the system in 1961. All of the stations on AM and FM signed off and the only AM signals were on 640 k.c. and 1240 k.c. I had recently purchased an FM radio shortly before that and on opposite ends of the FM dial, Conelrad signals could also be received although I don't know the m.c. they were on.
During that time, I had a speaker from an old car radio that was attached to the ceiling in the attic and used as an extra speaker for an old floor radio. If you connected that speaker to an input of my reel-to-reel tape recorder, it used to pull in WLW Radio which always amazed me. When that test alert took place, I checked that connection as WLW (like the other stations) was off the air. It was picking up the Conelrad broadcast and it could be heard farily well.
It might be noted that during that 1961 test, TV stations stayed on the air and featured national coverage of the alert, showing how people were responding to it, etc.
With regards to Conelrad, I remember the test alert of the system in 1961. All of the stations on AM and FM signed off and the only AM signals were on 640 k.c. and 1240 k.c. I had recently purchased an FM radio shortly before that and on opposite ends of the FM dial, Conelrad signals could also be received although I don't know the m.c. they were on.
During that time, I had a speaker from an old car radio that was attached to the ceiling in the attic and used as an extra speaker for an old floor radio. If you connected that speaker to an input of my reel-to-reel tape recorder, it used to pull in WLW Radio which always amazed me. When that test alert took place, I checked that connection as WLW (like the other stations) was off the air. It was picking up the Conelrad broadcast and it could be heard farily well.
It might be noted that during that 1961 test, TV stations stayed on the air and featured national coverage of the alert, showing how people were responding to it, etc.
Nostatic1 said:
The system was fairly simple...transmitters were designed in ranges, the any transmitter that was on the lower band 540 to 1000 or so were fitted with a 2nd crystal, on 640, and the 1010 to 1600 (at the time) (not sure of the exact split) were fitted with a 1240 crystal. when a test, or national emergency was declared, it was simply a plate off (turn the high power off) for a second, switch the crystal) and resume transmitting, but in this case, the station was now broadcasting on 640, vs say 910.
I seem to remember some slight tuning/loading of the antenna, ( which was simply turning a knob on the front of the transmitter), but keep in mind that the stations did have full time engineers at the time. It wasn't a difficult change though...
The other thing i remember was the conelrad test, because it used the carrier going off to trip the receiver. The test would start, the transmitter was turned off for 5 seconds, on for five, off for five, then back on with a 20 second tone after that...I don't remember if we changed the frequency, I don't think we did, but the crystal switch was right next to the plate switch, at least on the RCA's.
knowbetter said:
The EBS test worked that way until 1973 or 1974. You turned the transmitter carrier off for 5 seconds, and hopefully back on 5 seconds later. Off for 5 again, and hopefully back on after that. I say hopefully, because that was the point that some transmitters didn't want to come back on.
That system was replaced with the two tone EBS system that still exists in part with the EAS system today. The two tones were a great way to trip decoders without turning off the transmitter, and they had a distinctive sound which people came to know as the emergency alert tone.
When I first started working in radio, many year ago, I remember the old Conelrad receiver was located behind me while working on the air. At that time we monitored WHAS for alerts. During the late fall and winter months, when sky-wave propagation started early, the WHAS signal would start to fade around 5 PM causing the Conelrad receiver to make the sound of a ruptured duck in excruciating pain. Unlike today's radio, we had an expanded fifteen minute local, state and national news cast and yes it was read live from the control room. After several interruptions from the receiver, I always turned off the alarm until the newscast was over.
greg.hahn said:
yep, experienced that a few times myself...which is why the procedure first included warming up the backup transmitter first! It's really never happened that often, but it was easier than the ensuing panic that would happen. For some darned reason, I seem to remember those test in the middle of the day!~
greg.hahn said:
guess it's nice to see our memories haven't fades in out old age...
(translated) Boy, are we old!
Hey, in the spirit of the season, lets flip this topic to Christmas!knowbetter said:
http://www.youtube.com/watch?v=t039p6xqutU&ob=av2e
In keeping with the topic, my wife and I recently visited the Titan Missile Silo near Tucson AZ. Wow! What an experience to see how it was during those cold-war days especially for the ones who maned the silo and radio equipment. For my fellow ham operators, you can listen and broadcast on the Discone antenna installed on the site by Collins in the early 60s.
http://www.titanmissilemuseum.org/index.php
http://www.titanmissilemuseum.org/index.php
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