US2236102A - High frequency wave transmission system - Google Patents

High frequency wave transmission system Download PDF

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Publication number
US2236102A
US2236102A US204735A US20473538A US2236102A US 2236102 A US2236102 A US 2236102A US 204735 A US204735 A US 204735A US 20473538 A US20473538 A US 20473538A US 2236102 A US2236102 A US 2236102A
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US
United States
Prior art keywords
dipole
line
waves
wave
sheath
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
US204735A
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English (en)
Inventor
Frederick A Kolster
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
INTERNAT TELEPHONE DEV CO Inc
INTERNATIONAL TELEPHONE DEVELOPMENT Co Inc
Original Assignee
INTERNAT TELEPHONE DEV CO Inc
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Filing date
Publication date
Priority to NL61755D priority Critical patent/NL61755C/xx
Priority to BE434031D priority patent/BE434031A/xx
Priority to FR853438D priority patent/FR853438A/fr
Application filed by INTERNAT TELEPHONE DEV CO Inc filed Critical INTERNAT TELEPHONE DEV CO Inc
Priority to US204735A priority patent/US2236102A/en
Priority to GB12403/39A priority patent/GB527988A/en
Application granted granted Critical
Publication of US2236102A publication Critical patent/US2236102A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03H—IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS
    • H03H7/00—Multiple-port networks comprising only passive electrical elements as network components
    • H03H7/01—Frequency selective two-port networks
    • H03H7/0123—Frequency selective two-port networks comprising distributed impedance elements together with lumped impedance elements
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01Q—ANTENNAS, i.e. RADIO AERIALS
    • H01Q21/00—Antenna arrays or systems
    • H01Q21/06—Arrays of individually energised antenna units similarly polarised and spaced apart
    • H01Q21/08—Arrays of individually energised antenna units similarly polarised and spaced apart the units being spaced along or adjacent to a rectilinear path
    • H01Q21/12—Parallel arrangements of substantially straight elongated conductive units

Definitions

  • the present invention relates to wave blocking devices and to transmission line arrangements incorporating such devices and adapted. for feeding waves to a restricted portion of a conductive structure while preventing the waves from passing out over the remainder of the conductive structure.
  • the invention likewise relates to transmission line arrangements incorporating such devices and adapted for receiving waves collected by a restricted portion of a conductive structure while suppressing the reception of waves collected by other portions of the conductive structure. More particularly the invention relates to dipole antenna structures and means for feeding the same, or for leading energy away from the same, Without distorting the radiation pattern so as to render it unsymmetrical.
  • a vertical dipole and lead-in arrangement whose horizontal patterns of radiant action, 1. e. the sections in all horizontal planes, shall all be undistorted circles, and whose vertical patterns, 1. e. the sections in all vertical planes through the axis, shall all be alike and shall be adjustable in shape and inclination.
  • Such an arrangement in which the shape and inclination of such vertical patterns may be readily adjusted by adjusting the eifective length and height of the dipole.
  • the outer conductor of the coaxial line is connected to the tubular lower limb of the dipole only at the central point of the dipole, and the lower limb of the dipole is designed to be of exactly such length that it will resonate with the corresponding portion of the outer sheath of the leadin line, as a quarter-wave line so as to block the transmission of the high voltage and high current waves of the dipole over the outer conductor of the coaxial lead-in line.
  • neither limb of the dipole can be varied-to produce the desired adjustments of the radiation pattern since the length of the lower limb is inherently fixed by the requirement that this lower limb itself must resonate as a quarter-wave line to suppress the passage of the oscillatory energy of the dipole into the lead line, while the length of the upper limb is fixed by the requirement of balance between the two dipole limbs.
  • this wave blocking device may be adjustably moved along the continuous conductor which forms both the outer conductor of the lead-in line and the lower arm of the dipole antenna, the length of the lower arm of the dipole antenna may readily be adjusted without providing any telescopic members or other cumbersome and complex arrangements for the purpose.
  • the wave blocking device of my invention is also independently adjustable to tune it to exact antiresonance at the desired frequency, so that it is not necessary to pre-design the apparatus exactly for a given frequency, but rather the apparatus can be approximately designed and then adjusted.
  • the wave blocking device of my invention is also useful in other combinations and in itself,
  • Fig. .3 represents a lead-in arrangement for separately feeding a plurality of dipoles in an array
  • Fig. 4 is an elevation partly in section of the wave blocking device which is incorporated in the systems of Figs. 1 and 2;
  • Figs. 5, 6, '7 and 8 are partially sectioned elevations of further forms of wave blocking devices which may be used in the systems of Figs. 1 and 2.
  • Fig. 9 illustrates a form of wave blocking deduced by other antennae or by parasitic reflectors.
  • the dipole l is supplied with ultra-short waves from the source 2 over the coaxial line 3, the sheath of this coaxial line forming the lower limb of the dipole and the central conductor of the coaxial line being extended to form the upper limb of the dipole.
  • a telescopic extension 4 is provided at the end of the upper limb of the dipole for adjusting the length of this limb.
  • the effective electrical length of the lower limb of the dipole is determined by the position of a wave blocking device 5 which is slipped over the sheath of the coaxial line 3 and clamped thereto, and 1 which serves as hereinafter explained, to block the passage of Waves traveling down over the sheath of the coaxial line.
  • the cap, or upper portion 6 of the wave blocking device 5 is electrically a part of the lower limb of the dipole so that this lower limb may be regarded as extending from the center of the dipole to the lower edge of the cap 6, thus having the length B as shown in the figure.
  • the lower portion 1 of the blocking device 5 is electrically at the same potential as the lower half of the coaxial line 3, which is preferably at ground potential.
  • the upper limb of the dipole has a length A as shown in Fig. 1. Because of the fact that the lower limb of the dipole is larger in diameter than the upper limb, and has at its end the extended capacity surface of the cap 6, the lengths A and B should be slightly different in order to provide the same equivalent electrical length for the two halves of the dipole I.
  • the upper limb of the dipole may be increased in size so as to be similar to the lower limb, and in case exact symmetry is essential the upper extremity of the dipole may be provided with a cap similar the coaxial line 3 are in push-pull relationship or phase opposition, and since the potentials at corresponding points of the inner and outer conductors are equal and opposite, the waves traveling upward through the coaxial line 3 will have substantially no external effects and will pass unblocked throughthe device 5 which is located entirely outside of the coaxial line 3, as previously mentioned.
  • the waves On arrival at the center of the dipole I, the waves will spread upwardly along the upper half of the dipole and downwardly over the lower limb of the dipole, just as in the case of waves supplied to an ordinary dipole from a transmission line connected to the dipole from one side.
  • the upward waves along the upper limb of the dipole will be partly radiated and partly re flected from the open termination of the dipole.
  • the downwardly traveling waves on the lower limb of the dipole will be partly radiated and partly reflected, the reflection in' this case occurring at the lower edge of the cap 6 which effectively acts as an open termination aslater explained.
  • thewave distribution on the dipole is generally similar to the wave distribution on an ordinary dipole fed by a lead-in line Which joins the dipole from one side.
  • the design of the apparatus with respect to impedance matching and with respect to the standing wave pattern may under most ordinary conditions be made in accordance with the accepted theory of dipoles fed by lead-in lines separately connected from the side, while at the same time the distortions of the radiation pattern which would be introduced by the presence of a lead-in wire asymmetrically positioned with respect to the dipole, are completely eliminated.
  • the dimensional values and impedance relationship required for impedance matching or for producing a given standing wave distribution may be in general determined in accordance with the known theory of separately fed dipoles.
  • Fig. 1 Under one particular condition, however, the arrangement of Fig. 1 will differ in respect to the standing wave distribution and impedance relationship from an equivalent dipole separately fed by a transmission line connected to the dipole from one side.
  • a condition arises either when an unbalanced wave containing a longitudinal or cophasal component is supplied to line 3 for feeding the dipole or when the two arms of the dipole are for some reason made of unequal electrical lengths so that the reflected waves returning to the center of the dipole do not arrive at the center of the dipole in phase opposition.
  • the dipole will behave in a similar manner to an ordinary dipole with respect to waves traveling in push-pull fashion up or down the transmission line, so that with respect to such balanced or push-pull waves the feeding of the dipole and the matching of impedances may be effected in accordance with the well-known theory.
  • the arrangement of the present invention eliminates any possibility of such excitation of the dipole.
  • a dipole fed in accordance with my invention not only is free from the distortions due to a lead-in line disposed alongside of the dipole so as to distort the field of the latter, but also is inherently free from longitudinal waves or waves which are not in true phase opposition, even if the source or the two halves of the dipole are slightly unbalanced.
  • Fig. 4 is an elevation partially in section which more clearly shows the exact construction of the wave blocking device 5.
  • the wave blocking device 5 consists essentially of the cap 6 and the body portion 1 as generally indicated in Fig. 1. Both the cap and the body portion are provided with screws 8 which serve to clamp these portions to the sheath of the coaxial line 3, and the two portions 6 and l are shaped so that together they define with the sheath of the line 3 an annular or roughly toroidal cavity 9.
  • the body por tion I is provided with a flange l0 which is normally closely adjacent to the cap 6 so as to form a capacity therewith.
  • the value of this capacity may be adjusted so that .this capacity together with the inductance of the toroidal cavity 9 forms an anti-resonant wave suppressor circuit tuned to the frequency of the waves to be blocked.
  • the cap 6 is preferably provided with a down turned rim to prevent the entrance of rain or snow into the cavity 9.
  • suitable draining means may be provided at the bottom of the body portion I.
  • the wave blocking device 5 When the wave blocking device 5 is properly tuned to anti-resonance with respect to any given frequency, it operates as a very efiicient wave suppressor and almost completely blocks passage of longitudinal or cophasal waves over the line 3. With wave lengths of the order of two and onehalf meters a suppression of approximately twenty decibels may be provided by one single wave suppressor of convenient dimensions constructed as shown in Fig. 4. The dimensions of the wave suppressor may be very small in comparison with the wave length to be blocked.
  • the axial length which is preferably the largest dimension, should be substantially less than onequarter wave length and preferably of the order of one-tenth wave length or less.
  • the cap portion 6 and the body portion 1 may be clamped to a further tube which fits closely over the outer sheath of the coaxial line.
  • the body portion 1 or the cap portion 6 may be fixed with respect to this tube, leaving the other portion adjustable, but preferably that portion of the wave blocking device which lies toward the waves tobe suppressed should be fixed with respect to the auxiliary tube so that adjustment of the other portion will not vary the apparent position of the wave blocking device even slightly.
  • the auxiliary tube to which both the cap 6 and body portion 1 are attached may then be adjustably clamped to the sheath of the coaxial line 3 so that the wave blocking device as a whole may be adjusted to any desired position.
  • the device shown in Fig. 4 and above described, is especially adapted for use in the position shown with the cap 6 at the top of the device so as to exclude moisture.
  • the device of Fig. 4 may be mounted in any position, and in any case it may be used. to suppress longitudinal or unbalanced waves traveling along the line 3 in either direction.
  • the device with the cap 6 lying toward the waves to be suppressed since this cap ordinarily has less surface area than. the body portion 7 and therefore the waves to be suppressed will extend over a smaller area.
  • the construction shown in. Fig. 5 may be advantageously used.
  • the structure of Fig. 5 is generally similar to that of Fig. 4, but a downwardly depending rim is provided on the body portion instead of on the cap in order to exclude the weather when the device is mounted with the body portion above the cap.
  • Fig. 6 The structure shown in Fig. 6 is also similar in principle to the structure of Figs. 4 and 5, but in this structure both portions have approximately equal surface areas, and the capacity surfaces are positioned approximately at the center of the toroidal cavity 9, as clearly shown in Fig. 6.
  • the structure shown in Fig. 7 may be preferred in cases where it is desired to reduce the diameter of the wave blocking device.
  • This structure has no radially extending flanges but rather the cap and body portions overlap one another axially so as to provide a capacity between two concentric surfaces.
  • a wave blocking device of the type shown in Fig. '7 may advantageously be used and then each limb of the dipole may be built out or enlarged to the same diameter as the wave blocking device so that there will be no discontinuity in either limb of the dipole.
  • the upper one of these two devices may be adjusted to provide a desirable termination characteristic or reflection coefiicient for the lower limb of the dipole, while the second wave blocking device located immediately below the first one may be adjusted to more completely attenuate the downwardly traveling Waves so as to keep them out of the lower portion of the coaxial line 3.
  • the arrangement shown in Fig. 8 may be advantageous.
  • two wave blocking devices are constructed as a single unit having a common cap portion 6 and two body portions '1 and 1'. All three portions of the wave blocking device of Fig. 8 may be directly clamped to the coaxial line 3 by screws 8 or may be'clamped to an auxiliary tube which is then clamped over the coaxial line as described with respect to the structure of Fig. 4.
  • Fig. 3 schematically represents an arrangement for feeding two separate dipole antennae over two separate coaxial lines. Such an arrangement may be desirable in directive arrays or may even be used for separately transmitting two different signals on two separate antennae with the same carrier frequency.
  • two dipole antennae I and I are each supplied with ultra-short waves from the transmitting apparatus 2 over two separate coaxial lines 3 and 3'. Adjacent each antenna a wave blocking device 5 or 5' is provided to suppress the passage of waves down the coaxial line.
  • an additional wave blocking device H is provided at an intermediate point between the antennae and the transmitting apparatus 2.
  • Such auxiliary wave blocking device I! may be arranged as shown to block waves along both coaxial lines simultaneously.
  • the details of construction of the wave blocking device may be more clearly seen in Fig, 9.
  • the wave blocking device I is essentially similar to the wave blocking device 5 as shown in the other figures, and especially is similar to the device shown in Fig. 4.
  • the device H is arranged to surround two separate coaxial lines 3 and 3' and provides instead of a simple toroidal cavity 9, a figure 8 shaped cavity 9. If the two coaxial lines 3 and 3 are arranged in very close proximity, however, the cavity 9 may constitute substantially a toroid instead of a figure 8. In such a case waves traveling in push-pull fashion over the two inner conductors of the two lines would not be blocked.
  • Fig. 2 represents a transmitting beacon for providing course indications for aircraft.
  • the dipole is fed over a coaxial line 3 from the wave source 2 and is terminated by the telescopic end section 4 and the wave blocking device 5 just as described in connection with Fig. l.
  • the rotationally symmetric radiation pattern of the dipole I must be modified to produce a useful course indicating pattern, and for this purpose the two reflecting dipoles 2
  • is provided with adjustable telescopic extensions at each end similar to extension 4 of dipole I, in order that the reflecting dipoles may be tuned so as to produce. the desired radiation pattern.
  • are provided with relay 22 and 32 for rendering the two reflecting dipoles alternately efiective according to the desired keying code.
  • the relay 22 is arranged so that its contacts are normally closed, thus connecting together the two halves of dipole 2
  • Lines 23 and 33 connect the two relays to the inner and outer conductors of the coaxial line 3 at the center of dipole I as shown, choke being provided to prevent the fiow of high frequency over the lines 23 and 33.
  • the wave source 2 is arranged so as to supply not only ultra-short waves but also suitable coded direct current control voltages over the line 3 for actuating the relays 22 and 32.
  • the relays are so arranged that in response to a simultaneous direct current voltage applied to both relays over line 3 the relay 22 will open its contacts to disable dipole 2
  • the direct current control voltage over coaxial line 3 relay 32 -should release so as to disable the reflector dipole 3
  • the wave blocking device 5 operates in the same manner as the wave blocking device 5 shown in Fig. 1, and serves in exactly the same way to terminate the lower limb of the dipole I.
  • the ultra-short waves for energizing the dipole 1 from the source 2 pass upward in push-pull or phase opposition relationship over the line 3 so that these are not blocked by the device 5. Also the direct current control voltages are not in any way affected by the presence of the wave blocking device 5.
  • any of the antenna systems of Figs. 1, 2 or 3 may be used as receiving antennae by substituting a receiving equipment for the sources of waves 2 in Figs. 1 and 2.
  • the element 2 of Fig. 3 has been designated as either a transmitting or receiving apparatus.
  • the wave suppressor unit of my invention may also be used not only for blocking waves, but also for partially blocking such waves or generally for controlling the transmission and reflection thereof.
  • the wave blocking unit of my invention may likewise be used for suppressing waves in transmission systems not involving any antenna, as for example, in systems for transmitting waves from point to point over a coaxial line.
  • wave blocking units in accordance with my invention may be employed to control the transmission of longitudinal waves not only in coaxial lines but also in shielded lines having two or more conductors within one sheath.
  • a conductive shell around said sheath at an intermediate position along said sheath, said shell being shaped to enclose an annular cavity around said sheath, and capacity means for tuning said shell to a desired frequency whereby the transmission along said line of waves of said frequency may be controlled.
  • a coaxial transmission line having a sheath, a discontinuity at one position in said line, a conductive shell around said line at a second position on said line and outside said sheath, said shell being so shaped as to enclose an annular cavity around said sheath, means for turning said shell to a frequency to be transmitted over said line, and means for varying the distance between said discontinuity and said conductive shell by independent changing of said first and second positions on said line.
  • a coaxial transmission line having a sheath and an inner conductor, and a resonant device coupled to said sheath for controlling the transmission along said line of waves of a certain frequency, which comprises a hollow shell shaped to enclose an annular cavity around said line, said shell being conductive and forming about said cavity a one-turn toroidal conducting circuit and having a gap interrupting said circuit, and capacity means forming a lumped capacity across said gap whereby said device is tuned to said certain frequency.
  • a multi-conductor transmission line having a sheath and a resonant device coupled. to said sheath for controlling the transmission along-said line of waves of a certain frequency which cedar prises a hollow shell shaped to enclose an annular cavity around said line substantially less than' one-quarter wavelength in axial length at said frequency, said shell being conductive and forming about said cavity a one-turn toroidal conducting circuit and having a gap interrupting said circuit, and capacity means forming a lumped capacity across said gap whereby said device may be tuned to said certain frequency.
  • a coaxial transmission line and a resonant device according to claim 2 said device being slidably positioned on said sheath whereby said device may be adjusted in position along said line.
  • a radiant acting system for operation at a certain frequency comprising a radiant action dipole having a hollow first limb and a second limb, a multi-conductor transmission line ex tending to said dipole, at least one conductor of said line passing through said hollow first limb and connected to said second limb and a wave blocking device below said dipole comprising a shell enclosing an annular cavity around said line substantially less than a quarter wavelength in axial length at said frequency, and means for turning said shell to said frequency whereby waves of said frequency may be blocked from passing over said sheath.
  • An antenna system for operation at a certain frequency which comprises a coaxial transmission line having a sheath and an inner conductor, the inner conductor being extended beyond the end of the sheath to form a first dipole limb, a wave blocking device on said sheath spaced a distance from the extended inner conductor comprising a shell enclosing an annular cavity around said sheath substantially less than a quarter wavelength in axial length at said frequency, and means for tuning said shell to said frequency, said device being so tuned as to substantially block the passage of waves flowing over the outside of said sheath whereby the portionvof the sheath between the said device and the end of the sheath constitutes a second dipole limb.
  • a plurality of coaxial transmission lines each having a sheath, a conductive shell around said lines at an intermediate position along said line, said shell being shaped to enclose an annular cavity around said sheaths, and adjustable capacity means for tuning said shell to a desired frequency whereby the transmission along said lines of waves of said frequency may be controlled.

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  • Variable-Direction Aerials And Aerial Arrays (AREA)
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US204735A 1938-04-28 1938-04-28 High frequency wave transmission system Expired - Lifetime US2236102A (en)

Priority Applications (5)

Application Number Priority Date Filing Date Title
NL61755D NL61755C (pt) 1938-04-28
BE434031D BE434031A (pt) 1938-04-28
FR853438D FR853438A (pt) 1938-04-28
US204735A US2236102A (en) 1938-04-28 1938-04-28 High frequency wave transmission system
GB12403/39A GB527988A (en) 1938-04-28 1939-04-25 High frequency wave transmission systems

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US204735A US2236102A (en) 1938-04-28 1938-04-28 High frequency wave transmission system

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US2236102A true US2236102A (en) 1941-03-25

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US204735A Expired - Lifetime US2236102A (en) 1938-04-28 1938-04-28 High frequency wave transmission system

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US (1) US2236102A (pt)
BE (1) BE434031A (pt)
FR (1) FR853438A (pt)
GB (1) GB527988A (pt)
NL (1) NL61755C (pt)

Cited By (12)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2419855A (en) * 1939-06-22 1947-04-29 Roosenstein Hans Otto Arrangement adapted to suppress radio frequency currents on conductors
US2613319A (en) * 1950-03-18 1952-10-07 Westinghouse Electric Corp Adjustable antenna
US2663847A (en) * 1950-05-20 1953-12-22 Int Standard Electric Corp Phase changer
US2669695A (en) * 1952-09-23 1954-02-16 Breeze Corp High attenuation shielded lead structure
US2805414A (en) * 1955-05-26 1957-09-03 Itt Antenna structure
US3393384A (en) * 1964-08-28 1968-07-16 Nasa Usa Radio frequency coaxial high pass filter
US20130113667A1 (en) * 2008-03-05 2013-05-09 Ethertronics, Inc. Antenna and method for steering antenna beam direction
US9872327B2 (en) 2008-03-05 2018-01-16 Ethertronics, Inc. Wireless communication system and related methods for use in a social network
US10033097B2 (en) 2008-03-05 2018-07-24 Ethertronics, Inc. Integrated antenna beam steering system
US10056679B2 (en) 2008-03-05 2018-08-21 Ethertronics, Inc. Antenna and method for steering antenna beam direction for WiFi applications
US10116050B2 (en) 2008-03-05 2018-10-30 Ethertronics, Inc. Modal adaptive antenna using reference signal LTE protocol
US10263326B2 (en) 2008-03-05 2019-04-16 Ethertronics, Inc. Repeater with multimode antenna

Cited By (17)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2419855A (en) * 1939-06-22 1947-04-29 Roosenstein Hans Otto Arrangement adapted to suppress radio frequency currents on conductors
US2613319A (en) * 1950-03-18 1952-10-07 Westinghouse Electric Corp Adjustable antenna
US2663847A (en) * 1950-05-20 1953-12-22 Int Standard Electric Corp Phase changer
US2669695A (en) * 1952-09-23 1954-02-16 Breeze Corp High attenuation shielded lead structure
US2805414A (en) * 1955-05-26 1957-09-03 Itt Antenna structure
US3393384A (en) * 1964-08-28 1968-07-16 Nasa Usa Radio frequency coaxial high pass filter
US20130113667A1 (en) * 2008-03-05 2013-05-09 Ethertronics, Inc. Antenna and method for steering antenna beam direction
US8648755B2 (en) * 2008-03-05 2014-02-11 Ethertronics, Inc. Antenna and method for steering antenna beam direction
US9872327B2 (en) 2008-03-05 2018-01-16 Ethertronics, Inc. Wireless communication system and related methods for use in a social network
US10033097B2 (en) 2008-03-05 2018-07-24 Ethertronics, Inc. Integrated antenna beam steering system
US10056679B2 (en) 2008-03-05 2018-08-21 Ethertronics, Inc. Antenna and method for steering antenna beam direction for WiFi applications
US10116050B2 (en) 2008-03-05 2018-10-30 Ethertronics, Inc. Modal adaptive antenna using reference signal LTE protocol
US10263326B2 (en) 2008-03-05 2019-04-16 Ethertronics, Inc. Repeater with multimode antenna
US10547102B2 (en) 2008-03-05 2020-01-28 Ethertronics, Inc. Antenna and method for steering antenna beam direction for WiFi applications
US10770786B2 (en) 2008-03-05 2020-09-08 Ethertronics, Inc. Repeater with multimode antenna
US11245179B2 (en) 2008-03-05 2022-02-08 Ethertronics, Inc. Antenna and method for steering antenna beam direction for WiFi applications
US11942684B2 (en) 2008-03-05 2024-03-26 KYOCERA AVX Components (San Diego), Inc. Repeater with multimode antenna

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Publication number Publication date
BE434031A (pt)
NL61755C (pt)
GB527988A (en) 1940-10-21
FR853438A (pt) 1940-03-19

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