» Portland Radio

1953 The Morning All Stations Broadcast On 640 Or 1240kc

(14 posts)
  • Started 4 years ago by Craig_Adams
  • Latest reply from scowl

  1. Craig_Adams
    Radio historian

    The Sunday Oregonian - June 28, 1953


    Portland area residents will have a new experience Monday [June 29, 1953] morning when Conelrad, the device of the Federal Communications Commission, the Military and Civil Defense to keep radio stations in operation during an enemy attack and still deny use of radio beams to enemy bombers and guided missiles to find targets, gets its first workout.

    Eight Portland stations and one each at Oregon City and Vancouver, Wash., will participate in the test, from 1 to 2 a.m. Monday. The Portland area test is part of a Nation-wide inauguration of the system.

    This Is What Will Happen In The Portland Area:

    The stations will be silent at 1 a.m. as is their custom each Monday morning. Promptly at 1 o'clock the ten will begin broadcasting over two wave lengths entirely new to Oregon Washington listeners. Five stations will broadcast on 640 kilocycles, five on 1240 kilocycles. These are the frequencies assigned over the United States and Canada for exclusive use of official Civil Defense broadcasts.

    Stations On Briefly

    Each station in the cluster group using 640 kilocycles will be on the air not more than 30 seconds. It will switch off at the end of that period and another of the five will pick up the common program. They will rotate in that manner through the one-hour period. Stations in the 1240-kilocycle cluster will do the same. The effect however, is expected to be that of a continuous broadcast.

    This alternating of stations employs one of the lessons we learned at Pearl Harbor, Japanese bombers got a "fix" on the Honolulu radio beam and rode it to their target. But a bomber must have the radio signal 30 seconds or longer to get its "fix." United States Air Force planes determined that in testing the Conelrad plan.

    Rapid alternating of stations is designed so that none will be on the air long enough for an enemy bomber or guided missile to get a "fix" and "home" on that radio beam to its target. Conelrad's purpose is to fill the air with many confusing beams that shift from one to another of many stations. During an actual attack they probably would come from hundreds of stations over the entire North American continent, because it is the expectation to have Mexico and Alaska tied into the program.

    Name Derivation Explained

    The theme of the one-hour Monday morning broadcast will be a discussion of Conelrad (contraction of the words "CONtrol of ELectromagnetic RADiation"); explanation of the attack warning system worked out by the Military and Civil Defense training program.

    Purposes of the test were explained Friday afternoon over radio station KEX by Sherman Washburn, KEX Newscaster, in two broadcasts from the "secret" broadcasting studio of the Portland Civil Defense. One purpose is to test the efficiency of the tie-in of the ten participating stations, the other to acquaint listeners with the new 640 and 1240-kilocycle frequencies. Listeners are asked to mark these spots on the dials of their receivers so they can be easily tuned in, and to determine which of the two is more easily received.

    Jack Lowe, Director of The Portland Disaster Relief and Civil Defense agency, pointed out that while the test will include only the Portland, Oregon City and Vancouver stations, the listener area will be much wider. During actual emergency the origin of broadcasts at Portland or any other city would not be identified. Listeners could identify stations only by recognizing the voices of the men at the microphone.

    Two Frequencies Assigned

    The Conelrad plan would limit all the radio broadcasting to official announcements (the reason why radio must be kept on the air) and those only on the two official Civil Defense frequencies. Any other station broadcasting during such an emergency period would do so unofficially and could be presumed to be subversive. Lowe said the Federal Civil Defense agency and the U.S. Air Force are vitally interested in the forthcoming Conelrad tests at Portland and elsewhere. They have a considerable financial stake in the program. In the Portland area alone the FCDA and USAF will pay about $750 a month in toll charges on leased wires to tie the participating stations together.

    Participation by radio stations is entirely voluntary. Mayor Fred L. Peterson said success of the Conelrad operation will be due to the co-operative interest and assistance on the radio stations, which also will be at considerable expense in carrying on the program. Conelrad actually is ready to function at any time an emergency arises and clusters similar to the two five-station clusters are organized at Eugene and in the Coos Bay-Coquille area. In cities where there are not enough stations to form a sequential or cluster system, these stations will broadcast vital messages by the "on-off" method. They would be on the air from 10 to 30 seconds, then off from two to six minutes, so that no enemy bomber could "home-in" on their beams.

    After the first test nothing was written in "The Oregonian" on how it went, leading one to believe not well. A second test of Conelrad was conducted on September 16, 1953. Then the next day, this:

    The Oregonian - September 17, 1953


    Progress has been made, but technical problems remain to be solved to make Conelrad fully satisfactory to the listening public, Jack Lowe, Portland's Director of Civil Defense, commented Wednesday [Sept 16, 1953]. Liaison officers of the 25th Air Division, who monitored the test on the ground in Portland, were satisfied, Lowe reported. But many who listened to 640 and 1240 on their radio sets, 1:30 and 4:30 a.m. were confused by gaps and garbled intervals in the transmissions which might disrupt vital announcements Lowe said.

    Posted on July 9, 2014 - 06:31 AM #
  2. kennewickman

    Pulsing the carriers on for 30 seconds , off for two minutes ! For one hour long..back in those days of all tubes ..the contactors on and off (unless you did it in a driver stage, which is possible ) ...God almighy what a maintenance nightmare to say nothing of the logistics of it computers to do all that hand or some inventive engineer who built some kind of a timer driven device to do it all...geezus..and then what if an actual *situation* came up where you had to do this all day long ! What a cluster ..

    Posted on July 9, 2014 - 06:48 AM #
  3. Deane Johnson

    Conelrad was a typical government mess.

    Posted on July 9, 2014 - 10:25 AM #
  4. jr_tech

    "Conelrad was a typical government mess"

    But given the technology available at the time how would you design a better system to deliver warnings and yet not provide a stable target to lock onto?
    I bet a few final amplifier tubes died during these operations. :(

    Posted on July 9, 2014 - 10:58 AM #
  5. DarkStar

    My understanding was that they ended up finding no evidence the Japanese used radio transmissions to target Hawaii - this also contributed to the amounting list of problems that eventually caused Conelrad to be discontinued.

    Posted on July 9, 2014 - 11:38 AM #
  6. Alfredo_T

    Years ago, I had read that 1950s-1960s era AM transmitters often could accept three crystals: the main crystal, a backup crystal, and one cut for a CONELRAD frequency. However, switching frequencies would also require retuning of all the transmitter's RF stages and the antenna tuning unit!

    I have been wondering whether turning the carriers on and off would have been done by staff at each station, or if the central command center would have sent a control signal to each station, along with the program audio.

    Posted on July 9, 2014 - 01:25 PM #
  7. Deane Johnson

    My guess is that the station staff did it. I don't think there was much in the way of remote control of transmitters at that time. Anything that would have existed would have been pretty primitive.

    Posted on July 9, 2014 - 03:53 PM #
  8. KE7JFF

    One of the old timer engineers I have met in my travels worked at WGY-AM in Schenectacy, NY told me that they DID try to use their AM Transmitter on one of the CONELRAD frequencies without retuning it and found it would "work" but the signal would be much much weaker.

    I was always skeptical of the Ruskies or anyone else using RDF on broadcast tramsmitters during that time period; considering that Pearl Harbor was obvious to attack.

    Posted on July 9, 2014 - 05:11 PM #
  9. Dan_Packard

    A remnant of Conelrad must have been the old requirement to turn the carrier off for 5 seconds, then back on for 5, off, then on, during emergency broadcasting system (ebs) tests.

    Posted on July 9, 2014 - 05:16 PM #
  10. semoochie

    Just about any radios, from that period, had little Conelrad markers, on the dial, at 640 and 1240, to assist tuning.

    Posted on July 9, 2014 - 07:30 PM #