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{
    "localId": "486498091",
    "label": "Report, OSI - 3/49, Central Intelligence Agency, Vacuum Tube Development at Oberspreewerke and Its Significance to Soviet Electronic Developments",
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    "id": "486498091",
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    "contentType": "document",
    "title": "Report, OSI - 3/49, Central Intelligence Agency, Vacuum Tube Development at Oberspreewerke and Its Significance to Soviet Electronic Developments",
    "citationUrl": "https://catalog.archives.gov/id/486498091",
    "collections": [
        "President's Secretary's Files (Truman Administration)",
        "Intelligence Files"
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    "productionDates": [
        {
            "day": 28,
            "logicalDate": "1949-10-28",
            "month": 10,
            "year": 1949
        }
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{
    "seq": 21,
    "pageIndex": 0,
    "type": "photo",
    "url": "https://s3.us-east-1.amazonaws.com/NARAprodstorage/lz/presidential-libraries/truman/hst-psf/602196/875491/875491-02-021.tif",
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    "ocrText": "SECRET\nmoved. This is essential in order that the regeneration should remain in the required\nphase over the whole band. On the outer casing of the generator there is a scale, which\nenables the operator to move the pistons adjusting the elements to the necessary posi-\ntion for the generation of any wavelength of the band covered. (Note: This has been\ncopied from the US. The whole problem is mechanical coupling of the several moving\nparts so as to operate on a single knob.)\nOne use to which the wide wave-band generator may be put is the testing of met-\nalloceramic triodes intended for work over a wide band. For this purpose, a power load\nis connected to the generator with a special measuring lamp (probably neon) and a photo-\ncell. (Note: This is a very elementary method first used in the US but had been replaced\nby better methods by 1941.)\nThe basic technical data and OSW claims for the wide-band generator are as\nfollows:\nRanges: 8 to 15.5 cm and 16 to 24 cm.\nWith anode voltage at 800 volts and cathode current at 100 ma, high frequency\npower from 2 to 10 watts may be obtained.\nA generator with such a wide wave-band in the centimeter and lower decimeter\nbands has never existed before. (Note: Such has certainly existed in the US, if\nnot in Germany. If the first in Germany, or even if believed the first, this\npoint is significant.)\nTube LD11 - This tube differs from the LD12 in design in that the stems leading\nfrom the cathode to the anode-grid area are inside the tube, to effect a capacitative re-\ngeneration. The arrangement constitutes a built-in leak around the grid for use as an\noscillator only.\nSome of the principal characteristics of the tube are:\nHeater voltage\n12.6 V\nHeater current\n0.75 - 0.88 amp\nMinimum wavelength\n11 cm\nAnode voltage\n800 V\nCathode current\n100 ma\nA test set, type 6431, has been designed to test metal-ceramic triodes type LD11\nfor generation of oscillations. The set is formed from a system of two oscillating circuit\nelements - the anode-grid and the grid-cathode with the tube under test installed in the\nsystem.\nA test set, type 6432, has also been designed to test type LD12 tubes in serial\nproduction.\nTube LD9 - Metalloceramic triode for operation as self-excited oscillator (CW\noperation or pulsed modulation), and also for amplification (direct amplification and\ndoubling of frequency). (Note: It might be designated an \"all purpose\" tube.)\nConstruction: metalloceramic with radiator on anode\nVibration testing: 5 g (at amplitude of 0.55 mm, f = 50 cps)\n(Note: Indicates weak mechanical structure inasmuch as our tubes withstand\n100 g)\nStatistical data measured with radiator screwed to anode\nCathode: oxide, with indirect heating\nHeater voltage: 12.6 V (underheating to 11.3 permissible but without guarantee\nof effect on emission)\nHeater current: 1.1 amp\nMinimum wavelength: 15 cm\nAnode voltage (constant operation): 2500 V, max\n- 17 -\nSECRET"
}