t Approved For Release 2008 08 05 5 5' why-rain - QCQQOYB - DEPARTMENT OF THE NAVY Office of the Chief of Naval Operations Washington as o c BWL From Director of Naval Intelligence To Distribution List Op 922F2 jr Ser 018531P92 29 May 1963 Subj Tests of East German Subminiature Tubes U Ref ONI 56 of June 6 1956 entitled Evaluation of Certain Soviet Marine Electronic Equipment Spec of 18 June 19 67 for Electron Tube Type 1am Encl 1 Report on Subminiature tubes 1 This report summarizes results of tests of East German vacuum tubes conducted by the New York Naval Shipyard These tubes were among the few subminiature types ever recovered from the Soviet Bloc capable of use at fairly high radio frequencies The tube samples were made in the VEB RFT Werk fuer Fernmeldewesen 08W East Berlin in May 1962 This plant has been considered the most capable tube plant in East Germany 2 As indicated in the report the tubes were very similar to the U S Raytheon I ung Sol type 1AD4 a sharp cutoff ruf pentode used in rut and audio applications in small portable equipments The British Mullard DF-62 and the European subminiature tubes are considered equivalent to the Raytheon Tung Sol model there is no proof which tubes were used as proto- types The two tubes two samples each are indicated as and MON-21096 respectively 3 The test results indicated the tubes were reasonably satisfactory equivalents to the comparable U S tubes as in many prior tests of Soviet-Bloc tubes such as those outlined in reference It is an interesting tribute to the technology of East Germany as of 1962 vintage that this is the case although the Western prototypes date in design from the mid fifties It is verified that the East Germans can produce subminiature tubes of reasonable modernity comparable to U S and West European standards despite con- tinued reports of production difficulties GE GE GRKOVIC By direction DOWNGRADING AT IN TERVALS NOT AUTOMATICALLY DECLASSIFIED DOD DIR 6200 10 -- Approved For Release 2008 08 05 Approved For Release 2008 08 05 CONFIDENTIAL 8 88083 TECHNICAL REPORT REPORT OF TUBES 2109523 MON 210% NcIchl Scientific Technical Intelligence Center OFFICE OF NAVAL INTELLIGENCE AT CONFIDENTIAL NOT AUYOMATCALLY DECLIQSSIFIED Approved For Release 2008 08 05 CIA-RDP80T00246A000500120002-1 Approved For Release 2008 08 05 1 CONFIDENTIAL Report on Subminiature Tubes 1 study and evaluation were performed on' two groups each comprising two subminiature tubes procured irom East Germany The objective of the assignment was to determine the function Operational characteristics durability and reliability of the sample tubes as part of the Foreign Material Exploitation Program The two groups of tubes are designated MGM-21095 and In this report the four sample tubes are also identifiable by numbers 11 and 12 for the tubes of group MUN-21095 and numbers 21 and 22 for those of group MON-21096 respectively 2 Consideration was given to methods high lighting a previous exploitation study or subminiature tubes similar to the subject tubes Due to the limited time available this report is restricted to the evaluation of the tube functions and electrical characteristics excluding those necessitating destructive tests The report further presents details of the physical structure and chemical composition of the tube components and also offers comments on the work manship 8 A visual inspection revealed that subject samples were E s-lead subminiature tubes with flat press bases and T2x3 envelopes On all sample tubes one lead later identified as the original No 3 was cut flush with the tube base and all remaining leads cut to 1 4 inch approximately There was no recognisable marking of any kind on the envelopes nor was there any reference indicating pin Number 1 The inspection con rmed that the tubes were filamentary pentodes with spring loaded filaments using beam forming plates for suppressor grids 4 In the absence of any information concerning the tube types or the appropriate test voltages and in view of the very limited total number of samples available 4 particular precautions were taken to prevent electrical or physical damage to the tubes For the purpose of establishing a basis for determining the test voltage conditions and on the assumption that the foreign tubes may be cOpies of or similar to one or more USA types an extended study was made of USA subminiature types of similar size envelope and structure The following tube types were tentatively selected as possible equivalent or near equivalent types of the foreign tubes 1AD4 1AH4 5678 5875 5972 6051 2E31 2E32 2E35 2 35336 Based on the analysis of exhaustive preliminary parameter measurements all but one USA type 1AD4 were eliminated However USA type 11034 revealed marked similarities in electrical characteristics the size of enveIOpe electrode structure and even pin arrangement since the tubes under investigation can be considered 5-1ead tubes due to the cut- off pin This change to a 5 lead tube appears to confirm the intended similarity to the 5 lead oval base USA type CONFIDENTIAL Approved For Release 2008 08 05 Approved For Release 2008 08 05 CONFIDENTIA 1AD4 manufactured by Tang-Sol Raymeon However a difference between the two tube types is that tube type 1AD4 unlike the foreign tubes possesses a metallic paint external shield connected to lead No 3 suppressor 5 The investigation was directed toward determining the electrical character- istics of the tubes the physical dimensions structural details and chemical composition of the electrodes For the purpose of establishing the degree of equivalence two samples of USA type 1AD4 manufactured by Tung-Sol were included The results of the measurements and the test conditions are shown in Tables 1 and 2 and in Figures 1 2 and 3 8 It should be realized that irrefutable statistical results should be based on a much larger sampling than the four tubes available for this evaluation 7 Analysis of the electrical characteristics presented in Table 1 and Figures 1 2 and 3 reveals marked parametric similarities not only among the tubes of both subject groups MON-21095 and MON-21098 but also between these two groups and the USA type lADd The differences between the values of the parameters among the individual samples fall within the normal spread of the -- characteristics This is evidenced by the specification limits as shown in Table l The only exceptions seem to be several values of interelectrode capacitance which do not meet the applicable specification limits of the 1AD4 shown in parentheses It should be noted that the external shield of the 1AD4 was removed so that direct comparison of the interelectrode capacitance values could be made with the foreign tubes which do not have shields In general the subject tubes display higher plate resistances higher grid- cut-off voltage and in the Pulse Test Figure 3 reveal better pulse emission prOperties at below nominal filament voltage The Pulse Test also reveals that all samples under investigation were of above average working condition 8 The similarities previously mentioned between the electrical characteristics of the East German tubes and the USA type extend to the physical- characteristics structural details and chemical composition of the tube parts as shown in Table 2 The major areas of similarity are a The dimensions of the filaments and method of spring loading b The diameter and number of turns of the control and screen grid wires 0 The size and shape of the beam forming suppressor grid structure surrounding the plate d The area of the plate surfaces indicating equivalence of plate dissipation e The lead-to-electrode lay wont disregarding the cutuoif lead No 1 of the German tubes The mount structures g The coating of the mica spacers The chemical composition of the tube parts shown in Table 2 obtained by qualitative spectroscopic chemical analysis 2 CONFIDENTIAL Approved For Release 2008 08 05 Approved For Release 2008 08 05 CONFIDENTIAL 9 The physical and structural dissimilaritles observed are of minor importance and include the following a Structural diiferences in the getter assembly - I b Variations in tube bases 1 e flat press for the foreign tubes vs oval base for the USA type as manufactured by Thing-Sol c An extra mice is placed in the LAM underneath the getter to prevent leakage problems produced by the deposit of gettering material between electrodes d Type 1AD4 envelope is coated with a shield of metallic paint while East German tubes do not have a shield e The external leads of the USA tube are tinned those of the German tubes are copper p1ated f The cathode coating of the foreign tube is considerably thicker than that of the 1AD4 g The German tubes use the lead originally designated ush - with the tube base as additional support for the mount The USA counterpart uses two internal shaped wires for the Same purpose h In the East German tubes the shoulders of grid Number 3 and the plates anode are seated against the and bottom micas respectively thus providing greater rigidity for the mount structure In the USAJ type Isimilar construction is utilized with the exception of the lower plate shoulders which do not reach to the bottom mice 10 The following conclusions are drawn from this investigation a The East German subminiature tubes designated MON-21085 and are sharp cut off voltage amplifiers b Due to the close similarity of physical features chemical composition electrical characteristics and plate dissipation with type 1AD4 the East German tubes are considered as direct equivalents of USA type 1AD4 with identical range of application Design construction and workman- ship are considered of good quality c It is believed that the similarity of the subject tubes with the USA type 1AD4 is not accidental but probably intended since type 1AD4 is listed in MIL-STD-ZOOD dated 29 May 19 58 and thus by definition represents the best type available for a given function This type is also registered in the NATO Priority List for Electronic Tubes 11 No time was available to determine durability and reliability However in View of the marked similarities observed between the subject foreign and USA tubes in material construction and workmanship performance of these two tube types is expected to be similar The only exception is a possible longer life of the foreign type due to a heavier cathede coating Also it should be noted that the sample size was reduced to three tubes since sample No 12 of group MGM-21095 after the electrical measurements was subjected to rigid physical and chemical analysis 3 CONFEDENTLAL Approved For Reiease 2008 08 05                     National Security Archive    Suite 701  Gelman Library  The George Washington University    2130 H Street  NW  Washington  D C  20037    Phone  202 994‐7000  Fax  202 994‐7005  nsarchiv@gwu edu