Saint George

Discussion in 'Amplitude Modulation' started by W7TFO, Mar 9, 2017.

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  1. W7TFO

    W7TFO Premium Subscriber QRZ Page

    This isn't about the dragon guy, or someplace in Utah. The reference is about Mr. Westinghouse, whose company made a lot of the parts used in it.

    It is about a 1kW transmitter project, a recreation of a 1938-era plate modulated monobander for 75m.

    This story will have a run of at least a year, maybe longer as time to work on it is scarce.

    Built in a handmade aluminum framework, designed to 23" Bell System standards. Not quite a 'rack' job, but incorporating the ease of use they have.

    The frame is done, powdercoated in back wrinkle, and the thing stands almost 7' tall. So far, so good.

    An all MV full-wave plate supply, operating on 208V 3Ph with 6 rectifiers making that sweet 360Hz ripple.

    The audio channel: PP 6B4G's driving PP 211's, driving PP HF-300 triodes as modulators around 750W in class B.

    RF: That hetrodyne VFO with a 76, 42, and 802 pushing an 814 IPA into a marvelous Federal F-128A: See Franks' tube data for the dope on it.

    Much work has gone into the needed and proper parts for this; Cloth covered wire, terminals, sockets, metering, iron, filtering, RF parts, switches, even the right fasteners (NO PHILLIPS!).

    I'll post some pix of the present state of things, and some of the parts to be used.

    Stay resonant!

    AC0OB, K9ASE, N6YW and 4 others like this.
  2. WA3VJB

    WA3VJB Ham Member QRZ Page

    I'd rather stay non-linear, but that's just me.

    Your project sounds hihiFB
    AF6LJ likes this.
  3. AF6LJ

    AF6LJ Ham Member QRZ Page

    This is going to be Good. :)
  4. K5UJ

    K5UJ Ham Member QRZ Page

    Sounds like it will be a beautiful rig. I can't believe what people (AM Operators!) are asking for 211s now. Audiophool prices!!
  5. N2EY

    N2EY XML Subscriber QRZ Page

    Jug Southgate approves.

    Mid-1930s QSL card from W3ABT, the club station of the University of Pennsylvania:

    w3abtfrontL.jpg w3abtbackL.jpg

    Note the power supply....

    73 de Jim, N2EY
    N6YW likes this.
  6. N6YW

    N6YW Ham Member Volunteer Moderator QRZ Page

    I have seen the parts and the beginning stages of this project, up close in person.
    It's going to be breathtaking!
    Worth the wait!
  7. W7TFO

    W7TFO Premium Subscriber QRZ Page

    I have to straighten up the shop before I take pix, it is hard to discern the goods from detritus...

    Maybe today, and Billy N6YW plans to stop over manana for some iron so he might be able to help.

    Efforts ongoing...

    I love that old QSL with the 204A's on 3-ph. I have a few of them, waiting for the day...

    K9ASE likes this.
  8. N2EY

    N2EY XML Subscriber QRZ Page

    It's from my alma mater. Unfortunately, all of the pre-WW2 stuff was long gone by the time I arrived in 1972, although the callsign and the club were still there and in use.


    "The twelve rectifiers leaped into life as the contactors closed, the oil-filled reactors joining the inter-connected star neutrals, bursting into a 720 cycle song of increasing intensity."

    OK folks - what's that from?

    73 de Jim, N2EY
  9. WQ5Q

    WQ5Q Ham Member QRZ Page

    I seen the beginnings of this project also....very cool. I really love the beautiful cloth-covered wire. Set against the black wrinkle paint it will look very nice indeed.
  10. W7TFO

    W7TFO Premium Subscriber QRZ Page



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