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Super Power Triodes

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  • ozob99
    Anyone know what the final tube was in the Continental transmitters at the USN VLF stations at Cutler,ME & NW Cape(HOLT) AU? I know of the RCA 7835(with a
    Message 1 of 6 , Feb 14, 2008
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      Anyone know what the final tube was in the Continental transmitters at
      the USN VLF stations at Cutler,ME & NW Cape(HOLT) AU?

      I know of the RCA 7835(with a filament current of 6600A!)..but i'm
      thinking they were Machlett,Chatham or Eimac types.
    • taskforceleader
      ... at ... From the WWW: It has happened, although the last tour (last summer) was reported to be the last one to be held. Herre are some tidbits from my
      Message 2 of 6 , Feb 14, 2008
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        --- In coldwarcomms@yahoogroups.com, "ozob99" <ozob99@...> wrote:
        >
        > Anyone know what the final tube was in the Continental transmitters
        at
        > the USN VLF stations at Cutler,ME & NW Cape(HOLT) AU?
        >

        From the WWW:

        It has happened, although the last tour (last summer) was reported to
        be the last one to be held. Herre are some tidbits from my momory of
        that tour: NSS operated at one megawatt input power and about 800
        kilowatts output. Overall tranmitter efficiency was about one percent
        (radiated power vs. transmitter output) Total site power consumtion
        was about 1.5 megawatts, 24 hours a day, 7 days a week. The frequency
        of operation was 17.4 kilohertz. (although it is listed elsewhere as
        21.4 kc. This higher frequency may have been transmitted at another
        tower on the site.) The main tower is 20 feet square and 1200 feet
        tall, with outlying towers 800 feet high. Buried ground plane wires
        are located every three degrees under the elevated array. Total
        length of the array is about one mile end to end. The transmitter
        facility is under the array at one end. The litz wire used in the
        tuning system and main inductor was about five inches in diameter,
        and was made in Germany specially for this installation. Lightening
        only damaged the installation once in its operational life. Part of
        the 5-inch litz wire in the Helix house was damaged. Repairs were
        made by shortening the connections a bit because new wire was not
        available. The station transmittied frequency shift keyed telelype
        signals. The shift was very narrow and slow (25 Hz shift at a 50 baud
        rate) and placed the shifted carrier well down on the slopes of the
        sharp response of the antenna system on each side of resonance. The
        operator tuned the system from the console by watching for equal
        antenna currents on mark and space and tuning 5-foot diameter
        variometer coils by romote motor drive. Strong winds could de-tune
        the antenna system and cause unbalance in the transmitter. Final
        amplifier tube operating plate voltage was about 18 kilovolts at
        roughly 7 amperes to each of two final tubes in each of two
        transmitters... Power from the two transmitters was combined in the
        plate circuits to feed the antenna. There is no transmission line as
        such.. the feed wires carried current to the 1200 foot tower at three
        points.. The entire array is a capcity top loaded vertical. The
        capacitance of the antenna over its ground plane was tuned to
        resonance with a helical coil contained in the "helix house", a four
        story cubical shaped building next to the transmitter building.
        Transmitter tube lineup was 5933 (military 807) to 4-400's to
        4CX15000's to the final water cooled tubes. Two finals operated with
        one hot standby in each transmitter. A water cooled dummy load was
        available in the transmitter house allowing non-transmiting operation
        at reduced power. The last time final tubes were ordered from EIMAC,
        they cost $25,000 each. The onsite personnel never had any idea what
        information was being transmitted, since it was encrypted off site
        and sent via telephone lines to the transmitter site. ........ Some
        stories and memories of NSS personnel including historical photos can
        be found at: http://members.aol.com/k6dc/links.htm Some photos taken
        at the open house last summer (1998) can be seen at "The AM Window":
        http://www.thebizlink.com/am/ Specifically in the "Pictures" section
        at: http://www.thebizlink.com/am/pix/htm/nss1.htm Keep em Glowing!
        Roy, K1LKY since 1959 (now 40 years!) -- Roy Morgan 7130 Panorama
        Drive Derwood MD 20855 Home: 301-330-8828 (no fax or email at home)
        work: 301-975-3254 Fax: 301-948-6213 roy.morgan@... -- ----------
        -------------------- End of BOATANCHORS Digest 2642
      • ozob99
        ... Thats good info on Annapolis; i m looking for similar details on the NW Cape & Cutler transmitters, which I understand had double the power, at 2
        Message 3 of 6 , Feb 14, 2008
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          --- In coldwarcomms@yahoogroups.com, "taskforceleader" <mcfoster@...>
          wrote:
          >
          > --- In coldwarcomms@yahoogroups.com, "ozob99" <ozob99@> wrote:
          > >
          > > Anyone know what the final tube was in the Continental transmitters
          > at
          > > the USN VLF stations at Cutler,ME & NW Cape(HOLT) AU?

          Thats good info on Annapolis; i'm looking for similar details on the NW
          Cape & Cutler transmitters, which I understand had double the power, at
          2 MegaWatts.
        • beachmk4b
          I just joined the group so please excuse some replies to a few old unanswered threads. I ve been compiling info on Navy communications in the 1950 s-60 s at
          Message 4 of 6 , Feb 9, 2010
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            I just joined the group so please excuse some replies to a few old unanswered threads. I've been compiling info on Navy communications in the 1950's-60's at http://www.navy-radio.com - also restoring several tons of Navy gear for my "basement COMMSTA"

            I don't know about Holt's AN/FRT-67 xmtr yet.
            Cutler has an AN/FRT-31 xmtr with Machlett finals - "When operating at full power the antenna is fed by four separate 500-kw final amplifiers, each with eight ML-6697 air-cooled tubes operating in push-pull parallel. The antenna consists of some 62 miles of one-inch copper cable supported by 26 towers is a double star pattern, with the towers ranging in height from 800 to 980 feet."
            Photos and Info on Cutler at
            http://www.navy-radio.com/commsta/cutler.htm

            cheers,
            Nick

            --- In coldwarcomms@yahoogroups.com, "ozob99" <ozob99@...> wrote:
            >
            > Anyone know what the final tube was in the Continental transmitters at
            > the USN VLF stations at Cutler,ME & NW Cape(HOLT) AU?
            >
            > I know of the RCA 7835(with a filament current of 6600A!)..but i'm
            > thinking they were Machlett,Chatham or Eimac types.
            >
          • OZOB99
            ... Thanks for that update;seems the FRT-31 combining scheme is much like the Continental 105 series VOA used(in a recent thread); and nice page on Cutler.
            Message 5 of 6 , Feb 9, 2010
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              --- In coldwarcomms@yahoogroups.com, "beachmk4b" <navy.radio@...> wrote:
              >
              > I just joined the group so please excuse some replies to a few old unanswered threads. I've been compiling info on Navy communications in the 1950's-60's at http://www.navy-radio.com - also restoring several tons of Navy gear for my "basement COMMSTA"
              >
              > I don't know about Holt's AN/FRT-67 xmtr yet.
              > Cutler has an AN/FRT-31 xmtr with Machlett finals - "When operating at full power the antenna is fed by four separate 500-kw final amplifiers, each with eight ML-6697 air-cooled tubes operating in push-pull parallel. The antenna consists of some 62 miles of one-inch copper cable supported by 26 towers is a double star pattern, with the towers ranging in height from 800 to 980 feet."
              > Photos and Info on Cutler at
              > http://www.navy-radio.com/commsta/cutler.htm
              >
              > cheers,
              > Nick
              >
              > --- In coldwarcomms@yahoogroups.com, "ozob99" <ozob99@> wrote:
              > >
              > > Anyone know what the final tube was in the Continental transmitters at
              > > the USN VLF stations at Cutler,ME & NW Cape(HOLT) AU?
              > >
              > > I know of the RCA 7835(with a filament current of 6600A!)..but i'm
              > > thinking they were Machlett,Chatham or Eimac types.

              Thanks for that update;seems the FRT-31 combining scheme is much like the Continental 105 series VOA used(in a recent thread); and nice page on Cutler.

              Some more unanswered Naval gear questions are; details on:

              -VLF transmitters aboard the NECPA ships Northampton & Wright.

              -Tropo gear on the above ships and the shore stations.(REL 2600?)

              -UHF transceivers aboard the Wright and Dam Neck shore terminal
              (only used a short time as a trial before the tropo was up; I suspect
              one of the available airborne an/arc-xx units were utilized)

              -The crypto gear used to transmit SOSUS data from the NAVFAC's(KW-xx?)



              It seems the 1MW+ Super Power Triodes such as the RCA 7835 referenced above were used mostly,if not always,in research particle accelerators rather than communications transmitters.

              Photo's of a 7835 and cavity are on this page:

              http://www.contelec.com/pdf/CEC%20Capabilities.pdf
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