US2309063A - Directional radio beacon - Google Patents

Directional radio beacon Download PDF

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Publication number
US2309063A
US2309063A US363281A US36328140A US2309063A US 2309063 A US2309063 A US 2309063A US 363281 A US363281 A US 363281A US 36328140 A US36328140 A US 36328140A US 2309063 A US2309063 A US 2309063A
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US
United States
Prior art keywords
screen
radiators
directional
impedances
directional radio
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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
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US363281A
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English (en)
Inventor
Granqvist Carl-Erik
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AGA Baltic Radio AB
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AGA Baltic Radio AB
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Filing date
Publication date
Application filed by AGA Baltic Radio AB filed Critical AGA Baltic Radio AB
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    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
    • G01S1/00—Beacons or beacon systems transmitting signals having a characteristic or characteristics capable of being detected by non-directional receivers and defining directions, positions, or position lines fixed relatively to the beacon transmitters; Receivers co-operating therewith
    • G01S1/02—Beacons or beacon systems transmitting signals having a characteristic or characteristics capable of being detected by non-directional receivers and defining directions, positions, or position lines fixed relatively to the beacon transmitters; Receivers co-operating therewith using radio waves

Definitions

  • My invention relates to directional radio beacons.
  • Directional radio beacons are known, in which the direction of transmission is periodically reversed, to form the code letters e and t or a and n or with other code letters.
  • a listener who is on one side of a certain plane through the radio beacon will only hear the letter e (or a) whereas a listener on the other side of this plane will only hear the letter t (11).
  • the listener If the listener is travelling from one side of the radio beacon to the other he will pass a certain position, viz. the said plane, where he hears the signal e and the signal 1. simultaneously with equal intensity.
  • these signals were formed by shifting the direction of propagation of the beacon, the signals will complete each other, so that a continuous tone is heard.
  • radio beacons are usually called E-T- beacons.
  • the sharpness of the directional characteristic of this kind of beacon is relatively good, but it has been found that for certain purposes a greater sharpness is desirable. This is the case when the beacons are arranged as an aid for navigating in very narrow or difficult waters.
  • the present invention relates to an arrangement by means of which the sharpness of the directional characteristic may be varied as desired.
  • One special advantage of the invention is that the apparatus is very simple and dependable and the sharpness of the directional characteristic can be changed by changing only one simple directing means, no change in the parts associated with the radio transmitter being required.
  • Radio beacons of a standard type may be used and the directional sharpness may be varied as desired.
  • dipole antennas are used.
  • the dipole plane there is applied as a director a screen of metal or other conducting material, and the antenna is fed nonsymmetrically.
  • the field intensity diagram for a normal dipole antenna has the form of the letter 8. This is shown in Fig. l.
  • the dipole contains the two half parts ll and I2.
  • the directional characteristic is indicated by the curve l3. If a screen M, Fig. 2, of infinite extent is placed between the inner ends of the dipoles and connected to ground the transmission diagram is changed into the diagram shown in Fig. 2, composed of four loops. Between the two forms of the characteristic shown in Figs. 1 and 2, viz. for a dipole antenna with screen of zero extension and of infinite extension, there is an innumerable number of intermediate forms, produced by different screens with various finite, predetermined extensions.
  • Fig. 3 shows such an arrangement together with the characteristics, obtained by the same.
  • the invention is based upon the observation that the angle l5, at which the characteristic crosses the plane through the screen, varies from when the screen has zero extension (Fig. 1) to 0, when the screen has infinite extension (Fig. 2), and that thus any desired angle can be obtained by varying the extension of the screen.
  • Fig. 4 shows perspectively an arrangement according to the present invention, partly in block diagram.
  • the antenna in this arrangement is formed by dipole bars l6 and H, which are preferably made of pipes, and which are connected to the transmitter 3
  • a contact device 20 is provided'at the connection point of the conductors l8 and I9 to the antenna bars [6 and IT, respectively.
  • This may comprise a relay 2!, having a contact spring which makes contact with a back-contact 22, when the relay is deenergized and with a front contact 23 when the relay 2! is energized.
  • the counter-contacts 22 and 23 are connectedcharacteristics 26 and 21 for the antenna [6 andthe field characteristics 28 and 29 for the antenna IT, as shown in Fig. 3. Only one of these characteristics will be transmitted if one of the bars is connected to ground through the screen 25.
  • the backcontact 22 may be opened either after or before the front-contact 23 is closed. In both cases an audible click will be produced in the receiving apparatus. Such a click interferes with the observations and decreases the effectiveness of the very high theoretical sharpness of the directional characteristic.
  • Fig. 4 two contacts are used for the change of transmission. This can, however, also be produced by using only one contact, as shown in Fig. 5.
  • both of the dipole antenna parts are connected in a bridge coupling together with two impedances 32 and 33, two adjacent bridge branches being formed by the capacities to ground of the dipole antenna parts and the screen, respectively, whereas the two impedances form the two remaining branches.
  • the reference characters are otherwise the same as in Fig. 4.
  • the impedances 32 and 33 are connected to the screen, the impedance 33 directly and the impedance 32 through a contact 33, which is influenced by a relay 2i operated by a code mechanism 24.
  • the impedances 32 and 33 are not equal, the impedance 33 preferably being larger than the impedance 32.
  • the dipole antenna I6 is thus rendered partly inactive when the contact 34 is closed, as the impedance 32 is then acting as a short circuiting resistance, whereas with the contact 33 open the impedance 33 causes an unbalance in such a direction that the antenna I! is partly short circuited.
  • the characteristics are not reduced to zero, but they change between two unequal values, so that one or the other is greater depending upon whether the contact 34 is open or closed.
  • a clickless change over may also be obtained by a continuous switching system as shown in Figs. 6 and 7.
  • one of the impedances 32 has been replaced by a continuously variable condenser 42, which rotates and thereby continuously varies between a maximum value, corresponding to minimum of impedance, and a minimum value, corresponding to maximum of impedance.
  • the condenser 42 is mechanically controlled by a code mechanism 43, and the movement of this may not be at constant speed, but the speed may be varied in any suitable manner. It is especially suitable to use a pendulum movement or an oscillating movement, interrupted by shorter or longer periods of rest.
  • a more advantageous action is obtained by providing a difierential condenser as shown in Fig. 7.
  • the rotor 35 of this condenser is connected to the code mechanism, whereas the two stator parts 36 and 3! are fixed.
  • the rotor is electrically connected to the screen 25, whereas the stators 3G and 3'! are electrically connected it and H.
  • the changes of the load produced by the movement of the condenser may be compensated for by two symmetrical load compensation resistors 38 and 39 and a condenser 43 in a compensation circuit between the two stators 36 and 31.
  • the condenser 33 is mechanically controlled in accordance with the movement of the rotor 35, preferably by connecting the rotors of both of the condensers to the same shaft, but electrically isolated from each other.
  • both of the resistors 33 and 39 may be replaced by one common resistance although a certain unsymmetry may be thus produced.
  • a reflector may be used to eliminate the loops 2'! and 29 of the characteristic in Fig. 3, the loops 23 and 28 thereby being made correspondingly greater.
  • One suitable method of accomplishing this is to arrange in the screen It a numberof metallic bars 4
  • a metallic part of the transmitter itself, such as its chassis may be used as the screen if desired, to thereby obtain an easily transportable unit, containing the transmitter system as well as the antenna system.
  • a directional radio transmitter comprising a single dipole antenna having two oppositely extending linear radiators, a generator of radio frequency oscillations connected to feed said antenna, control means alternately rendering said radiators inactive, and a reflector screen between said dipole antenna radiators in a plane perpendicular to said radiators suited to alter the directional characteristics thereof.
  • a directional radio transmitter as set forth in claim 1 in which said screen is grounded and the control means comprises means for alternately connecting said radiators to said screen.
  • a directional radio transmitter as set forth in claim 1 in which the radiators are connected to said screen through impedances constituting, with the capacity of the radiators to ground, a bridge circuit and in which the control means Varies the value of one of said impedances so that the radiators transmit alternately with different field intensities.
  • a directional radio transmitter as set forth in claim 1 in which the radiators are connected to said screen through impedances constituting, with the capacity of the radiators to ground, a bridge circuit and in which the control means comprises a contact connected to open and close one of the branches of said bridge.
  • a directional radio transmitter as set forth in claim 1 in which the radiators are connected to said screen through impedances constituting, with the capacity of the radiators to ground, a bridge circuit and in which the control means varies the value of one of said impedances so that the radiators transmit alternately different field intensities, one of said impedances comprising a condenser which is continuously variable between a maximum and minimum value.
  • a directional radio transmitter as set forth in claim 1 in which the radiators are connected to said screen through impedances constituting, with the capacity of the radiators to ground, a
  • said impedances comprising a differential condenser having fixed plates connected to said radiators and a movable plate connected to said screen to provide a continuously variable control for the radiation characteristics of said radiators.
  • a directional radio transmitter as set forth in claim 1 in which the radiators are connected to said screen through impedances constituting, with the capacity of the radiators to ground, a bridge circuit and in which the control means varies the value of one of said impedances so that the radiators transmit alternately different field intensities, said impedances comprising a difierential condenser having fixed plates connected to said radiators and a movable plate connected to said screen to provide a continuously variable control for the radiation characteristics of said radiators and a variable balance circuit containing symmetrically arranged resistances in series with a variable condenser connected to said difierential plates, said condenser being actuated in unison with aid first condenser in a manner to avoid irregularities in operation during the change-over periods.
  • impedances comprising a difierential condenser having fixed plates connected to said radiators and a movable plate connected to said screen to provide a continuously variable control for the radiation characteristics of said radiators and a variable balance circuit
  • a directional radio transmitter as set forth in claim 1 in which an additional reflector is provided to direct the transmitted energy in a single direction only.
  • a directional radio transmitter as set forth in claim 1 in which a reflector is provided comprising a plurality of bars extending substantially perpendicular to said screen and parallel with said radiators, said reflector being adapted to confine the transmission to a single direction only.

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  • Engineering & Computer Science (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Radar, Positioning & Navigation (AREA)
  • Remote Sensing (AREA)
  • Variable-Direction Aerials And Aerial Arrays (AREA)
US363281A 1940-04-10 1940-10-29 Directional radio beacon Expired - Lifetime US2309063A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
SE549958X 1940-04-10

Publications (1)

Publication Number Publication Date
US2309063A true US2309063A (en) 1943-01-19

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Family Applications (1)

Application Number Title Priority Date Filing Date
US363281A Expired - Lifetime US2309063A (en) 1940-04-10 1940-10-29 Directional radio beacon

Country Status (4)

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US (1) US2309063A (en(2012))
FR (1) FR869411A (en(2012))
GB (1) GB549958A (en(2012))
NL (1) NL58146C (en(2012))

Also Published As

Publication number Publication date
NL58146C (en(2012))
GB549958A (en) 1942-12-16
FR869411A (fr) 1942-02-02

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