Category Archives: Civil Defense History

Trinity A-Bomb Test, 1945

Today marks the 70th anniversary of the Trinity nuclear test, the world’s first nuclear explosion, shown here 16 milliseconds after detonation.  The possibility of a fizzle led the team to construct a containment vessel dubbed “Jumbo,” a steel vessel measuring 25 by 10 feet, with steel walls 14 inches thick, capable of handling pressures of 50,000 PSI.  Brought from Ohio, it was the largest object ever transported by rail.

The blast was seen and felt in an area extending from El Paso, Silver City, Gallup, Socorro, and Albeuquerque.  One news article  quoted a blind woman 150 miles  away who asked, “what’s that brilliant light?”

 

The army issued a press release that a “remotely located ammunition magazine containing a considerable amount of high explosives and pyrotechnics exploded. There was no loss of life or injury to anyone, and the property damage outside of the explosives magazine was negligible. Weather conditions affecting the content of gas shells exploded by the blast may make it desirable for the Army to evacuate temporarily a few civilians from their homes.”

Other versions of the press release had been prepared noting fatalities.  The author of the press release realized that he might have been writing his obituary.

 

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1965 Emergency Broadcast System Simulated Script

Terrorism Section Content Nuclear Blast 1.3.0.0
A January 1965 report prepared for the Office of Civil Defense reported on several simulated fallout shelter exercises conducted in the Pittsburg area to investigate various shelter management factors. For example, in one study, the designated shelter manager arrived late. In another study, the effects of total darkness upon shelter operation were studied.




In three of the experiments, the stress level was increased by periodically playing simulated emergency broadcast system messages. The script of those broadcasts is particularly interesting, since it gives an insight into what civil defense planners thought might be a plausible scenario for a nuclear attack on the United States, and how news would be communicated to the public.

Here is the text of the nineteen radio broadcasts that might have been heard during a nuclear war:

EMERGENCY BROADCAST SYSTEM SCRIPT
EBS #1, Friday, 7:00 PM

ATTENTION. ATTENTION. This is the Emergency Broadcast System. Take shelter immediately. Take shelter immediately. This is not a drill.
Repeat: This is not a drill. An enemy attack is being launched against
the United States. Take shelter immediately and stay tuned to this
frequency for further instructions.

THE ABOVE MESSAGE IS TO BE REPEATED THREE TIMES, WITH 15-SECOND INTERVALS.

EBS #2, Friday, 7:10 PM

ATTENTION. ATTENTION. This is the Emergency Broadcast System. We have just been informed that the city is now on the emergency power system. Please inform the control center if your shelter is without light-., Repeat: The city is now on the emergency power system. Please inform the control center if your shelter is without lights. We also have ….. we also have word here that there has been no confirmed report of a missile strike in this area.  There has been no confirmed report of a missile strike in this area.

EBS #3, Friday, 7:15

(Phone is heard ringing in background.)

ATTENTION. ATTENTION. This Is the Emergency Broadcast System. A missile attack has been launched against the United States. Reports about the attack are fragmentary and unconfirmed. The strategic missile bases west of the Mississippi appear to have borne the brunt of the attack. As of this moment there has been no official report of a nuclear detonation in our immediate vicinity. Fallout has begun to descend on the western portions of our city and is expected in other areas imminently. Do not communicate with the emergency operations center unless absolutely necessary.

.
EBS #4, Friday, 8:00 PM

ATTENTION. ATTENTION. This is the Emergency Broadcast System. Stay tuned for an important message. (DISTANT VOICE: Okay, stand by now. We’ve got a remote from Washington.) Static ——- Noise. Another voice: This is a report from the emergency national command post in Washington. The President and his key civilian and military aides have been safely evacuated to the emergency seat of government. This evening at 6:35 PM the enemy launched an attack against the strategic retaliatory forces of the United States and its NATO allies. An intelligence warning allowed us to launch a portion of our land-based missile force against the enemy’s remaining strategic forces.
Polaris missiles have also been launched. In addition, our airborne alert and a portion of our ground alert aircraft forces have been sent against the enemy’s non-missile strategic forces. Our damage assessment reports indicate that many of our SAC bases have been destroyed or severely damaged. A number of communities near SAC bases have also suffered great damage. The fallout monitoring network reports that radiation is heavy in the western portion of our country and is increasing in the midwest and eastern portions of our nation. Although there have been several nuclear detonations in the east, it appears as if these have been the result of errant missiles, rather than a planned attack against population centers.  The President, whom, I repeat is alive and well, will address the nation as soon as his command duties permit. This is the end of the Priority One report. Local EBS stations may resume Priority Two broadcasting.

EBS #5, Friday, 8:30 PM

ATTENTION. ATTENTION. This is the Emergency Broadcast System. Short wave monitoring has disclosed that our air strike forces are currently launching attacks on the enemy homeland. These forces are utilizing a new….. what?  What do you mean it’s not for release? (Another voice: Priority One. Now.. for heaven’s sake! Announcer: Well what the hell …… 1)

THIS MATERIAL CUT OUT.

EBS #6, Friday, 8: 50 PM

Has this one been cleared?
ATTENTION. ATTENTION. This is the Emergency Broadcast System. We have Just received word that the President has been evacuated to sea in the floating Whitehouse. The location of this ship is unknown. The floating Whitehouse is a battle cruiser, fully equipped for command and control functions. Our government has survived the attack. I repeat, our government has survived the attack.

EBS #7, Friday, 9:30 PM

ATTENION. ATTENTION. This is the Emergency Broadcast System, We have just been informed that a message is to be delivered from the governor’s office in Harrisburg. Please stand by,

This is a report from the governor’s office in Harrisburg. The state of
conditions in Pennsylvania is serious, but not critical. Erie has been
severely damaged by what is believed to have been a stray missile. No other cities have reported being hit, but the fallout level is rapidly increasing, particularly in western Pennsylvania. Apparently neighboring states have borne the brunt of the attack, particularly those in the western portions of the country. All citizens should seek shelter immediately. Do not attempt to evacuate your area until you are instructed to do so. Local law enforcement personnel should remain in their respective areas. State police have been assigned to more critical areas, and additional state aid will become available and be assigned when fallout levels permit.

EBS #8, Friday, 10:15 PM

ATTENTION. ATTENTION. This is the Emergency Broadcast System. Fallout began to descend on the Pittsburgh area several hours ago and radiological monitoring reports indicate that radiation levels are dangerously high in many parts of our city. No one should attempt to leave shelters. Repeat: No one should attempt to leave shelters. Youngstown, Ohio and Erie, Pennsylvania have suffered severe damage as a result of nuclear detonations.
As of the moment there have been no nuclear blasts in our immediate area.  The municipal power has been temporarily disrupted in some parts of the city. Power should be restored shortly. No further official reports on our retaliatory attacks on the enemy homeland are available. Unofficially, the absence of any significant second wave of enemy attack, plus the size of our surviving strategic force, allows cautious optimism that we will suffer no further major damage from any attack. Until further word is transmitted by this station, everyone must remain in shelters.

EBS #9, Friday, 10:30 PM

ATTENTION. ATIENTION. This is the Emergency Broadcast System. In order to evaluate the damage to Pittsburgh, the emergency operations center requests every shelter to gather the following information and to report it to the local emergency operations center. Is this a fallout or a blast shelter? How many persons are in the shelter? How many of these persons are injured? How many persons are suffering from radiation sickness? What is the condition, of your equipment? Is your shelter structure damaged? Do you have adequate electricity?
Do you have adequate ventilation? What is the state of your food supplies? What is the state of your water supply? Do you have any illness other than radiation sickness? As soon as we have received reports from district control centers we will relay such information on to you. When emergency missions are possible, disaster teams will be sent to those shelters which need medical supplies, food and water. Attempts will also be made to report specific areas of damage in our city. Please stay tuned for additional announcements.

EBS #10, 11:30 PM

ATTENTION. ATTENTION. This is the Emergency Broadcast System. Wee have hundreds of people in the area who do not have shelter with an adequate protection factor. They must be moved to other shelters in order to survive.
Please advise the emergency operations center as to the number of additional people you can take into your shelter. This is imperative. Please inform the emergency operations center as to the number of additional people you can take into your shelter.

EBS #11, Saturday. 1:30 AM

ATTENTION. ATTENTION. This is the Emergency 3roadcast System. Radiological monitoring teams report that the radiation levels in the Pittsburgh area are still high. However, there is no additional accumulation of radioactive dust. The fallout on the ground is beginning to decay. It is simply a matter of waiting out this decay time before we can undertake further civil defense measures.  Everyone is to remain inside until further notice. Please do not leave your shelters.

EBS #12, Saturday, 2:15 AM

ACCIDENTALLY OVERHEAR A SHORT WAVE BROADCAST. “Hello Tower…. to checkpoint two…. ” Static and short wave noise.

EBS #13, Saturday, 3:00 AM

LOUD STATIC AND SHORT WAVE NOISE.

ATTENTION. ATTENTION. This is the Emergency Broadcast System.

EBS #14, Saturday, 3:45 AM

ATTENTION. ATTENTION. This is the Emergency Broadcast System. Reports have been received that there are bands of looters wandering about the city.  Attempts have been made to loot shelters in this area. Be alert to this situation and act accordingly. Security police will begin patrolling the area as soon as the radiation level permits.

EBS #15, Saturday, 4:15 AM

ACCIDENTALLY OVERHEAR SAC PLANE MESSAGE. Sounds like:
“Angels 46 — Same heading — Roger, Angels 52 — Fuel 30 … ”
Much static.

EBS #16, Saturday, 6:00 AM

ATTENTION. ATTENTION. This is the Emergency Broadcast Svytem. Stay tuned for an important message. Okay, stand by to switch.
MUCH STATIC ———– “Please stand by.”
This is a Priority One report from the emergency national command post in Washington. It appears that the enemy attack is over. There have been no further reports of missile strikes since early last evening. Radio monitoring indicates no further enemy air activity. Damage assessment reports indicate that the brunt of this attack was borne by western states. Many of our SAC bases have been destroyed or severely damaged. Communities near SAC bases have also been severely damaged. The central and eastern portions of the country have escaped extensive damage although stray missiles have struck some of the smaller population centers. Fallout is moving across the country in an easterly direction, carried on westerly winds. All citizens should remain in shelters until instructed otherwise by local civil defense commands. The President and key members of his cabinet are still aboard the U. S. S. Northampton. The President will address the American people as soon as his command duties permit.

This is the end of the priority ….. this is the end of the Priority One report. Local EBS stations may resume priority two broadcasting.

EBS #17, Saturday, 7:30 AM

ATTENTION. ATTENTION. This is the Emergency Broadcast System. Emergency teams have been established and have begun to operate in various sections of Pittsburgh. There is a shortage of able-bodied men to serve on work details in Shadyside, East Liberty, Bloomnfield, and Morningside. Will all shelters submit to the emergency operations center the names of able-bodied volunteers who may be asked to leave shelters before radiation levels are completely safe for permanent exit. Phone the names into the emergency operations center. Further information will be provided as to when and where the rescue volunteers will report.

EBS #18, Saturday. 10:00 AM

ATTENTION. ATTENTION. This is the Emergency Broadcast System. Weather monitoring teams report that there is a severe storm approaching the Pittsburgh area. What’s that? It appears that this storm is bearing with it a radioactive dust cloud and we expect the levels of radiation to increase severely. Some shelters do not have adequate protection facilities against this cloud. There is a possibility that some shelters will have to mobilize and be moved. (PAUSE) We will contact these shelters by phone within the next few minutes. Please do not call the emergency operations center. If your shelter is one of these that has to be mobilized and be moved, we will contact you. Please stand by.

EBS #19, Saturday 3:00 PM

ATTENTION. ATTENTION. This is the Emergency Broadcast System. Radiological calculations of fallout levels in Pittsburgh indicate that permanent exit from some shelters will be possible in the near future. At the present time recovery teams are surveying the city to locate and to prepare facilities for post-shelter operations. It is imperative that you do not attempt to leave your shelter without prior notice from the emergency operations center. There are still many dangerous radiological “hot spots” in the city. Therefore, regardless of the radiological readings in your immediate vicinity, wait for official notification. from your government in the emergency operations center.

THE END

For more insight into 1960’s civil defense, my website contains a scan of the 1962 St. Paul, MN, civil defense operational plan, which includes the manual that shelter managers would use in the operation of a fallout shelter.

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1965 Fallout Shelter, Livermore, California

One of three common rooms at the Livermore shelter. Doors lead to individual family rooms.

One of three common rooms at the Livermore shelter. Doors lead to individual family rooms.

On April 19-23, 1965, a symposium was held in Washington on “Protective Structures for Civilian Populations.” The proceedings of that symposium were published, and contain reports of a number of interesting fallout shelter concepts. Some were mere concepts, but one that had been implemented was a cooperative group shelter near Livermore, California.

The author of that report was Arthur J. Hudgins, who is identified as being with the Livermore Radiation Laboratory. He noted that both he and his associates had concluded that it would be economically practical to build a shelter sufficient for any attack, as long as it did not involve a large nuclear expolosion within three or four miles. But they also concluded that “the post-attack problems to be faced by a single family upon leaving a shelter would be most serious.” After much discussion, they concluded that a shelter group would have a good chance of not only surviving the attack, but also successfully meeting the later problems.

To carry out their plans, they incorporated as Survival Associates, Inc., a California corporation, and set out to build the shelter. By the time land had been procured and building began, 34 families had become members. Initially, obtaining the building permit looked problematic, since “fallout shelter” was not a use mentioned in the county zoning ordinance. But while the application was pending came the Berlin crisis, and the Board of Supervisors quickly came around to the need. The members concluded that the best design would be a corrugated steel arch covered by earth, set on a concrete slab measuring 25 by 142 feet.

Entry to the shelter. A more recent photo of what appears to be the same entry can be found at this site.

Entry to the shelter. A more recent photo of what appears to be the same entry can be found at this site.

The entry doors consisted of surplus steel ship doors, and there was a small room with a generator near each entrance. Near each entry was a shielded observation tower, which would provide a view of the surrounding countryside. Inside, there were 32 rooms for individual families, each measuring 7.5 feet square with an 8 foot ceiling. There were a total of six toilets and three kitchens.

One of the three kitchens.

One of the three kitchens.

Each kitchen was supplied by a 3000 gallon undergound tank, and each pair of toilets was served by a 1000 gallon tank. The tanks could also be refilled from the peacetime water system.

Common areas were lit with flourescent fixtures, and each room was equipped with a 100 watt lightbulb, which could be replaced with a 25 watt bulb if needed to extend generator run time in an emergency.

In addition to the main entries, there were multiple emergency exits, which consisted of sections of the steel structure that opened inward. These were covered with sand, which would fall inward if necessary to evacuate. Ventillation was provided by a positive-pressure system which pumped in outside air near the entries. During tests, the ventillation system proved more than adequate. In fact, when the ventillation system was shut off and the shelter sealed, most occupants did not notice.

The minimum earth cover over the shelter was four feet, which was calculated to provide a protection factor against fallout of more than 10,000. It was estimated that the structure would withstand a blast of up to 30 PSI. The corporation stocked the shelter with a three-week supply of food to supply 2000 calories per day per person. This consisted mostly of bulgar wheet, sugar, dried milk, vegetable oil, and viatimin tablets. In addition, there was dried fruit, coffee, tea, pancake flour, dry soup mix, peanut butter, and vitamin tablets. Most members also had food stored in their individual rooms, and it was estimated that the group would have an adequate diet for about six weeks.

In addition to other supplies, the shelter was stocked with about 1100 gallons of gasoline, which was calculated to be enough to run the generators for six weeks.

The shelter was equipped with a shortwave receiver, and there were “definite plans” to include an amateur radio transmitter.

At the time of the report, there were a couple of vacancies available, and there was also provision to build a second interconnected shelter at the same site if there was sufficient interest.

The corporation conducted some tests of occupancy. One of those was featured in a 1963 newspaper article.  In addition, members had access to the facility at all times with combination locks. During the Cuban Missile Crisis, a number of members stayed at the facility as a precaution.

 

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1958 Phoenix Fallout Shelter

w7pyhshelter

The cozy ham shack shown here is actually the fallout shelter of  William A. Rhodes, W7PYH.  (in the 1972 and 1993 call book, his call appears to have changed to W7KLA.) His Phoenix shelter, along with another one in California. appeared in the March 1958 issue of Popular Mechanics.

w7pyhAntennaHe had a well-equipped underground station.  The unit on top is a Heathkit DX-100 transmitter, beneath which sits an HRO Junior receiver.  The presence of the nameplate on the receiver suggests that this was a military surplus version of the HRO.  The station would have covered 160 through 10 meters.  The large unit on the floor appears to be the speaker/power supply for the receiver.  (The other unit on the floor to the right of the radio equipment is apparently a dehumidifier.)  The antenna, shown here, was a vertical mounted on the ventilation pipe, through which power to the shelter ran.

Power was apparently supplied by commercial power, or perhaps a generator mounted above ground.  The shelter’s floor plans, shown below, don’t make any reference to a generator.

Interestingly, the floor plans do show an oxygen cylinder.  While this might have been of limited utility, it is understandable given the owner’s background.

Rhodes was an inventor and founder of Arizona HydroGen Manufacturing, which manufactures an electrolysis unit which generates a mixture of hydrogen and oxygen which is used immediately for purposes such as welding.  The process seems relatively straightforward, and as far as I can tell, Rhodes never made any extraordinary claims as to it.  However, it seems to have received some attention from those who do make extraordinary claims as some sort of free energy source.  Since he was in the business of hydrolyzing, it’s not surprising that the shelter contained a canister of oxygen.

Rhodes seems to have been a prolific inventor in a variety of areas.  Most notably, he was the co-inventor of U.S. Patent 2594740, an electronic light amplifier with applications in astronomy and in television.  Remarkably, Rhodes’ co-inventor was none other than Dr. Lee De Forest, the inventor of the triode vacuum tube.

And Rhodes’ name is also well known in UFO circles, since he photographed a UFO in 1948.

Rhodes died in 2007 at the age of 90.  According to this site, the shelter remained intact as a computer room until his death.

Floor plan of the Rhodes shelter. Each room is 9 feet in diameter.

Floor plan of the Rhodes shelter. Each room is 9 feet in diameter.

 

 

References

 

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1958 Conelrad Monitor

1958PEconelrad

An article in the February 1958 issue of Popular Electronics admonishes that “all of us should use a receiver that warns when the Conelrad alert begins,” and the magazine offered a simple circuit, shown here. The concept was about as simple as possible: The little self-contained receiver monitored continuously. If the carrier of the local station disappeared, then a buzzer would sound.  Since all stations (other than designated stations on 640 and 1240) were required to leave the air during a CONELRAD alert, this would warn the owner of an impending attack.

It would seem that this particular design would be prone to false alarms. Obviously, it would work only with a 24-hour station. Otherwise, when the station signed off each night, the buzzer would sound until morning. And even most 24-hour stations signed off occasionally for transmitter maintenance. These periods often took place early Monday mornings, so someone relying on this receiver would probably get some rude awakenings if the receiver was left on.

And even though the receiver drew minimal current, it would probably go through the three penlight cells quite quickly.

But since hams were then required to monitor Conelrad, the receiver might have served a useful purpose, even though it probably wouldn’t work too well in continuous service.

1958PEconelradSchematicAs can be seen from the circuit here, the CK722 served as detector, and the 2N170 was hooked up to a relay, which would turn off the buzzer when the station left the air. The author, I.C. Chapel, notes that the relay is set to trip at 6 mA. At the conclusion of the article, there is an editor’s note stating that this figure “amazed” them, and concluded that the author must be very close to the broadcast station to get these results with his 10-foot antenna. One editor constructed the unit and tried it about 25 miles from New York City, and none of the stations there was strong enough to make the circuit work. With a more sensitive relay and a 150 foot antenna, though, they were able to get it to work with a 250-watt station 10 miles away.

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1955 CONELRAD Receiver

1955ConelradRXUnder the headline, “Are You Ready For CONELRAD?”, the April 1955 issue of Radio News carried the plans for this small CONELRAD receiver which could be easily carried in a pocket or glove compartment. The circuit is very similar to the Conelrad receiver carried by Boys’ Life the following year.  This receiver also consists of a crystal set followed by a one-transistor audio amplifier.

The article describes CONELRAD, and notes that “the responsibility of the individual citizen and particularly of the electronic technician and experimenter would be to provide themselves and their families well ahead of time with some means for receiving Conelrad broadcasts under any or all emergency conditions.” The article noted that receivers should be exactly calibrated, to avoid losing valuable seconds fumbling around trying to find 640 and 1240 on the dial. The article suggests using a signal generator to calibrate and mark the dial before an emergency.

1955ConelradSchematicIt then offers the circuit shown here, since it would be “highly advisable to have available at all times a portable battery-operated radio. The average portable radio is fairly cumbersome to carry about over any appreciable distance and its power requirements are high enough to make it impossible to keep in operation continuously.

The author notes that his original plan was to have one transistor serve as the detector, but had some difficulty in designing the circuit, due to the low input impedance of most transistors. Therefore, like the author of the Boys’ Life design, he settled on a diode detector, with one stage of audio amplification.

Unlike the Boys’ Life model, which was mounted in a cigar box, this one is mounted snugly in a small plastic box. The author notes that “as most old crystal set men will recall, a fairly long antenna and a good ground are required for best results.” Therefore, he recommended taping 25-50 feet of fine wire to the case for use as an emergency antenna.

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Fallout Shelter Communications Studies of the 1960’s

FalloutShelterCommunicationsStudy

One of the shortcomings of the fallout shelter program of the 1950’s- 1970’s was the lack of communications from shelters to the outside world. The 1962 Fallout Shelter Plan for St. Paul, MN, for example, stated that “many designated shelters will be in places with access to existing telephones. When telephones are available and operable they will serve as basic communications.” The plan also stated, but apparently with no thought as to who would be responsible, “plans should be made to insure that at least one battery operated AM radio receiver plus extra batteries will be made available in the shelter for reception of emergency broadcasting information.”

When I was a student in elementary school, I noticed these gaps. One year, during a tornado drill (that had been scheduled well in advance), I was quite pleased to see that one of the teachers had with him down in the basement a battery-operated radio. It was rather reassuring to see it, since I knew we wouldn’t be cut off totally from the outside world in the event of an emergency, since we would still be able to receive whatever emergency instructions might be forthcoming from the radio.

My reassurnce was dashed that afternoon, however, when I saw that same teacher walking home, carrying his portable radio. It was apparently his personal radio, which he brought to school in preparation for the scheduled drill. In other words, it wouldn’t be around in the event of an actual emergency. If the power were out, we would, indeed, be cut off from the rest of the world.

On another occasion, the school administration was going to have an additional twist on the drill. Instead of heading to the designated shelter when the school’s own bells sounded the warning, each class was instead going to act when the sirens outside went off. When we heard the siren, we were to head for the basement.

Unfortunately, the closest siren was miles away, and wasn’t very loud where we were. Undaunted, my classroom teacher had a solution to the problem. Shortly before the scheduled test, she opened a window at the back of the room, and a designated student sitting near that window was tasked with listening for the siren. The plan went off without a hitch. He heard the siren and warned the class, and we all headed for the shelter. Of course, it occurred to me that the window wasn’t normally left open. In an actual emergency, nobody would have heard the siren.

The 1962 St. Paul shelter plan realized many of these shortcomings, and stated that “two-way radio is being considered as back-up to telephone communication.” It also considered the possibility of using amateur radio. Under the heading of “other desirable equipment” was “portable transmitting-receiving equipment belonging to members of units of RACES (Radio Amateur Civil Emergency Service). Plans will be made to have designated ‘hams’ take their portable equipment to shelters upon receipt of warning.”

I’m not aware of any specific plans worked out to use RACES in fallout shelters. However, on the national level, there was indeed some planning taking place for two-way radio equipment in shelters. Even though some planning was done, as far as I’m aware, this was never put into place.

In a 1962 report entitled “Fallout Shelter Communications Study,” the engineers conducting this study used Montgomery County, Maryland, as an example, and determined what kinds of communication would be appropriate between the fallout shelters and Emergency Operating Center (EOC) in what the study considered to be a fairly typical county.  The report concluded that the telephone system should serve as the primary communications network for these needs, but also recognized the desirability of two-way radio, and came up with a budget of $391,000 for the county.  Each shelter’s radio was budgeted at a minimum of $250, with another $50 set aside for the antenna.

 

FalloutShelterTransceiverSpecifications for equipment were contained in a 1964 report prepared for the Office of Civil Defense by the same engineering firm. The sketch here of a prototype transceiver for shelter use is from that report.  This report provided specifications for the equipment in each shelter.  The radio for use in the shelters is shown here, and could be either VHF or UHF, in the 150, 460, or 950 MHz band.

A key concern in the design specifications was the fact that the radios would be left unattended for long periods of time.  Therefore, non-corrosive properties were important, and ferrous metals were to be avoided to the extent possible.

Power supply could be either 120 volts AC, or 12 volts DC.  The problems of storing batteries for long periods of time was a challenge, and consideration was given to storing dry batteries.  In addition, batteries from vehicles could be used.  Presumably, they would be brought into the shelter in an emergency.  If the battery needed replacing, presumably a short excursion out to the parking lot could be made when radiation levels decreased.

Ease of operation by untrained personnel was also a concern.  The unit did not have an external microphone.  Instead, both the microphone and speaker were built in, with a push-to-talk switch on the panel.  The only other control on the panel would be the volume control and power switch.  The unit was to have a squelch control, which would be accessible from the front panel.  However, it would be preset, requiring a screwdriver to make any adjustments.  It did include a headphone jack for private listening.

The cost for equipment was estimated at between $250 and $420 per shelter, with an additional $10 to $100 for the antenna, which would be installed prior to the emergency.

It was recommended that the radios be licensed as local government service, perhaps on the same frequencies as other municipal services.  It was anticipated that any necessary drills might be conducted on weekends, causing minimal interference to the other governmental users.

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Another Crystal Set for CONELRAD Reception

EmergencyXtalSetRadioTVExperimenter1955

60 years ago, CONELRAD was the system planned for keeping the American public informed in the event of a nuclear attack. As I’ve explained previously, the idea was for designated broadcast stations to operate on 640 or 1240 kHz. Stations would not transmit station identification, transmissions from individual stations would be short, and enemy bombers would be presented with a cacophony of signals useless for navigation purposes.

But power might be out. Battery-operated sets were rare, and most of those that existed sucked through expensive batteries quickly, since they had to power the filaments of the tubes. Undaunted, radio enthusiasts realized that a crystal set could be put to use. As I previously reported, Boys’ Life magaine touted a crystal set that could be put to use in an emergency.
Another Boys’ Life article included a CONELRAD receiver with one transistor that could run on two penlight batteries. And in a pinch, that set could be used without a battery, operating as a simple crystal set. And during the 1956 CONELRAD test, a Heathkit crystal set performed surprisingly well at receiving the emergency broadcasts, even outperforming commercial tube and transistor radios.

EmergencyXtalSetRadioTVExperimenter1955SchematicAnother example of crystal sets for emergency use is shown here, in the 1955 edition of Radio-TV Experimenter.  Author George P. Pearce (probably shown in the illustration above) describes the need:

If flood, tornado or air raids cause power failures, could you get emergency directions from the Conelrad stations the government has at 640 and 1240 on the dial? Even battery-powered sets couldn’t operate over an extended period of weeks, so why not build a crystal set that needs no power except the broadcast signal.

The author describes this set, which uses two 1N35 diodes along with two .001 uF capacitors in a voltage-doubler circuit. It uses basket-wound high-Q coils to pull in weak signals. It recommends a 100 foot antenna and good ground. He also suggests the use of the house wiring as an antenna, using a lamp cord, capacitor, and plug going in to the 120 volt house wiring. This ought to work, but if the power is on, you would be putting a lot of faith in that capacitor not being leaky as you put the headphones hooked to that antenna onto your head, just like they place the electrode of an electric chair.

The author notes that there’s nothing to wear out, and his set has operated for over three years.

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Sleep Alert: Warning the Public of Nuclear Attack at Night

A 1969 report prepared for the Office of Civil Defense details a proposal that was never adopted for a program called CHAT: Crisis Home Alerting Technique. In recognition of the fact that this military acronym wouldn’t be of much use with the public, a more descriptive name was proposed for dealings with the public: Emergency Broadcast System Sleep Alert.

The Emergency Broadcast System was designed to alert the public through normal broadcast stations of enemy attack. Sirens were available in many areas, but large portions of the population would be unable to hear them, especially at night. And at night, most Americans would be asleep, and not listening to radio or television. A nighttime attack would catch Americans by surprise, unless they were sleeping in shifts to listen to the news.



In a “bolt out of the blue” attack, the problem of nighttime alerts remained problematic. But during periods of strategic crisis, such as the Cuban Missile Crisis, CHAT or “Sleep Alert” provided an answer. During such a crisis, Americans could get their sleep, but also be able to receive warning. Upon determining that a crisis existed which might require warning the population, the President would activate the system, and the public would be notified to tune to participating stations in their area. The President would then make the following announcement, probably at 11:00 PM Eastern Time:

In a moment my voice will begin to fade; merely turn your volume up until you can hear me again. This is part of a system which will permit you to receive later emergency information. Please leave your receivers on constantly; when you wish to sleep, turn the volume down to a comfortable level, and I will be able to reach you my means of your radios and televisions.

The stations would then reduce their modulation to 10-20%. VHF TV stations would reduce the audio to zero. Viewers tuning in after 11:00 would know that they were tuned in, because they would see a message on the screen explaining that the station was operating in the sleep-alert mode. In addition, the detent tuning of VHF television receivers would ensure that the viewer was properly tuned in.

AM radio stations presented a problem, because listeners tuning in after 11:00 would need to know that their radio was tuned in to the proper station. Therefore, it was decided that “subdued materials” could be broadcast. The report noted that “the more exciting up-tempo kinds of music or the strident, demanding voice delivery techniques employed at many rock and roll stations” should be avoided. Instead, the program would be soft music or perhaps a clock ticking, with occasional station identification by “an announcer speaking softly but with calm authority” with the following message:

You are listening to the Emergency Broadcast System Sleep Alert. Stay tuned for a possible emergency warning from the United States Government. Adjust your radio volume to a level at which you can sleep. This station will resume broadcasting more loudly if warning is necessary. See your newspaper for more information.

Station personnel would then monitor the AP and UPI wires for warning messages. Stations without wire service would monitor Emergency Broadcast System primary stations. In the event of that fateful message, the station would turn up the volume to normal modulation, meaning that all of the listeners would confront a radio playing at full blast, which would presumably be enough to wake them. The station would then transmit a loud alert signal, followed by the following message:

Attack–Attack. The United States is Under Nuclear Attack. I repeat–the United States is under nuclear attack. Take shelter. Take shelter immediately. You are in danger–you can save your life if you take shelter immediately. This is the emergency broadcast system.

Assuming that there was no attack during the night, the station would gradually increase its modulation at 7:00 AM, and resume normal programming.  CHAT was viewed as an interim measure, and had the advantage of not requiring any new equipment either on the part of broadcasters or the public. The plan was to replace it eventually with a more reliable system. But as a stopgap, it had the advantage of being able to be adopted readily. It was, however, never adopted.

It was at least a decade before the first 24-hour warning system came into effect, in the form of alerts broadcast on NOAA weather radio in the mid-1970’s. However, it was always subject to question how well NOAA weather radio was integrated into the national warning system. However, NOAA now makes clear that it will broadcast Presidential alerts during a national emergency, and it appears to be well integrated into the National Warning System. Modern NOAA weather receivers, such as the one shown here, take advantage of digital encoding (SAME), which will limit the number of false alarms for weather events in surrounding areas.

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CONELRAD Test, July 20, 1956

Milwaukee Civil Defense Director Don E. Carleton and Col. Anthony F. Levno assess damage after simulated attack on Milwaukee. Milwaukee Journal, Jul. 20, 1956.

Milwaukee Civil Defense Director Don E. Carleton and Col. Anthony F. Levno assess damage after simulated attack on Milwaukee. Milwaukee Journal, Jul. 20, 1956.

At 3:10 PM Eastern Standard Time on July 20, 1956, CONELRAD conducted its first (and as far as I can tell, only) nationwide test. At that time, all radio and television stations left the air for 15 minutes, and the only broadcast signals coming from the United States were those of the CONELRAD system on 640 and 1240 kHz.

CONELRAD  was obsolete almost as soon as it was put into effect, but the idea was that during an enemy attack, attacking bombers must be deprived of the ability to use American broadcast stations for direction finding and navigation. Aviation routinely made use of AM stations for navigation, and the locations of broadcast stations and their frequencies are still printed on aviation charts. It was a reasonable concern, but it became much less critical when the bomber was replaced by the ICBM as the main component of both Soviet and American strategic war planning.

CONELRAD was created by President Truman in 1951, and hung on until 1963, when it was replaced by the Emergency Broadcast Sytem, in which participating stations continued to broadcast on their normal frequency.

Under CONELRAD, all stations in the U.S. would operate on the same two frequencies.  The navigator of an enemy bomber tuning to either of those frequencies would be confronted with hundreds of stations on the same frequency, rendering them useless for navigation.  And each station would transmit for only a few seconds or minutes.  In smaller markets with only one station, the station would quickly give instructions, and then sign off for a few minutes.  In larger cities, the stations would be linked together by telephone lines.  A continuous program could be sent, but it would switch quickly from one transmitter to another, hopelessly confusing enemy bombers.

But for those 12 years, CONELRAD was the method by which Americans would be warned of war, and in 1956, it was put to a test.  At 3:10 PM Eastern Time, each participating station was to transmit the program which had been delivered by record.  The introduction to this broadcast can be heard at the following YouTube video:

In many cities, such as Chicago, the CONELRAD test was conducted in conjunction with other civil defense exercises.  The Chicago Tribune for July 20, 1956, details some of the preparations being made there.  The next day’s paper  reports 325,000 simulated deaths in the Land of Lincoln.

There was surprisingly little reporting on how well the test went: Namely, whether the public was actually able to hear the broadcasts. One of the few actual tests was carried out by Radio News magazine, and reported in the October 1956 issue.

The magazine arranged receiving sites at four locations around the New York area. They were in a steel building in Brooklyn, a steel building in Manhattan, a home about 25 miles from the city, and a home about 50 miles from the city. At each location, writers for the magazine had multiple receivers ready for the test. They then rated the percentage of the broadcast they were able to receive intelligibly.

An outdoor antenna proved to be the greatest asset. At the home 25 miles from the city, the editor reported a 100% satisfactory signal using a Hallicrafters S-40 hooked to an outside TV antenna, and also with a Heathkit crystal set with a 100 foot outdoor antenna. At the same location, a Westinghouse battery portable without external antenna gave only 75% satisfactory reception.

In Brooklyn, the best performer turned out to be the Regency TR-1 transistor portable,
which gave a 100% reliable signal, but with continual retuning as the signal shifted from one transmitter to another. At the same location, the Knight tube portable was only 75% satisfactory, with the remaining signal too weak without reorienting and retuning the radio.

In Manhattan, the transistor portable, a Zenith Royal 500, outperformed the tube portable, with 85% satisfactory reception compared to 65%.

50 miles from the city, a Grundig tube portable gave 85% satisfactory reception, outdoing the Zenith portable, which had only 60% reliability. At this more distant location, the main problem came from interference from stations in other cities’ CONELRAD networks.

It is somewhat surprising that so much “retuning” was necessary. Presumably, the stations all had a crystal for their assigned frequency (the article didn’t state whether New York was using 640 or 1240), so it’s unlikely that the individual transmitters were drifting. More likely, some of the individual transmitters were slightly off frequency, resulting in the need to retune when the signal switched from one to another.

The article did stress the importance of having nondirectional antennas, something that was lacking in most AM portables. Most of the receivers, other than those using outdoor antennas, had to be reoriented when the signal switched transmitter locations. The article noted that extreme sensitivity wasn’t necessarily a good thing, because of the danger of interference from adjacent networks. These two factors explain why the crystal set had such good results in the test.

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