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Changing Rectifiers

Discussion in 'Amplitude Modulation' started by AC0OB, Aug 28, 2019.

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  1. AC0OB

    AC0OB Subscriber QRZ Page

    Grandpa Billy on right, "Gee, I hope someone remembered to throw the Master Power Supply Switch!" :D

    Changing Rectfiers.jpg

    K6RBK likes this.
  2. WZ5Q

    WZ5Q Ham Member QRZ Page

    Hmmm... that was probably way before "Lock-Out, Tag-Out" protocols were mandatory!
    N6YW likes this.
  3. N2EY

    N2EY Premium Subscriber QRZ Page

    Those little things? They're babies.

  4. W2VW

    W2VW Ham Member QRZ Page

    The old timers I knew did not utilize L.O.T.O.

    They believed in handcuffs.

    A handcuff is a grounded connection, physically connected to the dangerous supply(s) AND visible from the work position.

    Today's dangerous electronics present an interesting way of safety hardware implementation.

    The flow chart test does NOT allow a microprocessor to be relied on to keep anything de-energized.

    Real old time ancient caveman disconnects and/or circus breakers are required to satisfy industrial safety insultants.

    What's disturbing is when management types dictate procedure directly.

    Equally as disturbing is when someone forgets to remove handcuffs when attempting to return equipment to service.
  5. K4KYV

    K4KYV Subscriber QRZ Page

    Hams used to use mercury arc rectifiers before 872s and 866s came out. They are described in some of the mid-20s QSTs and early editions of the Handbook. An old timer brought one to the Dayton flea market one year, just to show it off, not to sell it. He was surprised that I knew what it was.

    They worked much like a MV rectifier tube, except there was no filament. The thing was tilted to one side and liquid mercury flowed between two electrodes to short out and start an arc. Then it was tilted back upright, and the sustained arc served as the cathode of the rectifier. There were two anodes in one envelope which allowed it to work as a full-wave rectifier. I believe the part of the glass envelope where the arc was, had to be submerged in oil for cooling. Otherwise the glass would melt or break. The arc had to be snuffed out at the end of each transmission and re-struck at the beginning of the next, since the RF hash would blanket the receiver.

    They had to make old buzzard transmissions; fast break-in would be difficult.
    K6RBK likes this.
  6. AC0OB

    AC0OB Subscriber QRZ Page

    A shootout and a mercury rectifier!

    One year I took the grandboys to Abilene KS to ride the steam locomotive train and to watch a High-Noon shootout.

    While waiting for the locomotive to be prepped we discovered that Abilene had one of the largest Telegraph and Telephone museums in the country. :cool:Since the boys had never used a rotary telephone, they used them to talk to each other over the internal lines. We sent Morse code as well over their Telegraph system.

    I noticed over in one of the corners they had this very large globe with wires coming out of it and what looked like a large tube inside. I remarked to the curator that it looked like an old Mercury rectifier. He said indeed it is and that is what the telephone company used at one time to power Central.

    He cordoned it off and had us step back while he energized it. It was very bright and buzzed with the most purplish light I have ever seen, very much like the mercury tube in the YouTube video.

    Darn, the train whistle just blew for boarding so we had to leave.:eek:

    Last edited: Aug 30, 2019
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  7. N2EY

    N2EY Premium Subscriber QRZ Page

    They are mercury-arc rectifiers. There was some use by amateurs in the 1920s-30s, and a few amateurs used them much longer.

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