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500,000 Watt Transmitter

Discussion in 'Announcements & Open Forum' started by r carl, Sep 23, 2020.

  1. r carl

    r carl Well-Known Member

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    Slowmover and Shadetree Mechanic like this.

  2. w9cll

    w9cll W9WDX Amateur Radio Club Member

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    I have toured that facility, it's a cool place. They only ran 500k at night and covered most of the USA and half the world
     
    #2 w9cll, Sep 23, 2020
    Last edited: Sep 24, 2020
  3. Road Squawker

    Road Squawker Sr. Member

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    33 volts @ 4500 amps............
     
  4. 543_Dallas

    543_Dallas Sr. Member

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    Typo?
     
  5. Captain Kilowatt

    Captain Kilowatt Professional Amateur
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    The PA tubes ran at PA voltage of 11.7 Kilovolts with a PA current of 65 Amperes, which yields a DC input power of 747.5 KW.
     
    Tallman and BJ radionut like this.
  6. Captain Kilowatt

    Captain Kilowatt Professional Amateur
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  7. Captain Kilowatt

    Captain Kilowatt Professional Amateur
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    EACH of the FOUR output tubes required 33 volts at 4500 amps just to light the filaments.
     
    DainBramage and 543_Dallas like this.
  8. w9cll

    w9cll W9WDX Amateur Radio Club Member

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    All custom made by RCA and Westinghouse
     
  9. nomadradio

    nomadradio Analog Retentive

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    Filaments of the final tubes were powered by three-phase AC.

    Got some pics around here somewhere from the last couple of visits.

    73
     
  10. Justme

    Justme Sr. Member

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    One thing is sure, I'm not going to pay their electricity bill....;)
     
    BJ radionut likes this.
  11. BJ radionut

    BJ radionut Supporting Member and 6m addict

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    WLW, Cincinnati, Ohio, was the first United States commercial 50 KW station and the only standard broadcast station to ever broadcast at a power of 500KW from 1934 to 1939! It was also the first to make use of a directional antenna system for skywave radiation control. (WSUN and WFLA, St. Petersburg, FL. shared the first directional antenna system.)
    It was called
    The Nation's Station and was started by Powel Crosley, a grand innovator of products and services from radios to automobiles.

    • Early 1933- WLW began construction of a new, first-of-its-kind 500,000 watt facility at Mason, Ohio with the approval of the FRC. A new $400,000 RCA 500 KW transmitter was installed at the site and a new 831 foot, 136 ton, half wave, Blaw-Knox double diamond-shaped vertical antenna was erected for $46,000. A 75 feet square, concrete lined pond was built in front of the building for transmitter cooling. Water was pumped through specially designed, water cooled tubes, then out through fountains which sprayed the water into the air and into the pond.
    • January 1, 1934- The FRC authorized WLW to use 500,000 watts on an experimental basis using the call W8XO.
    • April 17, 1934- The FRC issued a license to operate at 500,000 watts during regular hours under the WLW call letters.
    • Wednesday, May 2, 1934- WLW began experimental 500 KW broadcasting as Mrs. Franklin D. Roosevelt threw the switch at the White House desk in Washington D. C. Some saw the WLW call letters as signifying "Whatta Lotta Watts".
    February 28, 1939- WLW reverted back to 50,000 watts of power, ending the superpower experiments, except for the W8XO experimental license, allowing 500 KW operation between 12 midnight until 1:00 AM, which remained in effect until December 29, 1942.

    The tower height was decreased from its original 831 feet to 747 feet. The original height produced a groundwave/skywave cancellation ring which went through Columbus, Indianapolis, Lexington and Louisville. Lowering the mast pushed this ring out farther, away from those population centers. Also, back around 1934, two directional "suppressor" towers were constructed across Tylersville Rd. to the south-southwest to reduce skywave radiation toward the Canadian border. CFRB(Canada) was complaining of interference, so WLW reduced its power to 50KW until the "suppressor" towers were in place. As previously stated, this was the first use of skywave directional control for broadcasting.
     
  12. DainBramage

    DainBramage Well-Known Member

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    The original tubed used DC @ 33 volts, they were later changed to AC.
     
  13. Slowmover

    Slowmover Elmer

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    Crosleys bio a little too good to be true. But a great read (any online source).
     
  14. Tallman

    Tallman W9WDX Amateur Radio Member, KW4YJ EXTRA class

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    Isn't that just a pre-driver for you playtime amplifier??
     
    Captain Kilowatt likes this.
  15. 543_Dallas

    543_Dallas Sr. Member

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    I had plate supply on the brain. It's hard for me to even fathom that much filament current. I should have watched the video but I'm impatient. It's hard to speed read a video. :LOL:
     
    Captain Kilowatt likes this.

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