US2082825A - Radio communication system - Google Patents

Radio communication system Download PDF

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Publication number
US2082825A
US2082825A US736586A US73658634A US2082825A US 2082825 A US2082825 A US 2082825A US 736586 A US736586 A US 736586A US 73658634 A US73658634 A US 73658634A US 2082825 A US2082825 A US 2082825A
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US
United States
Prior art keywords
aerial
aerials
radiogoniometer
frame
rays
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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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US736586A
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English (en)
Inventor
Eckersley Thomas Lydwell
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RCA Corp
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RCA Corp
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Filing date
Publication date
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Publication of US2082825A publication Critical patent/US2082825A/en
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    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04B—TRANSMISSION
    • H04B7/00—Radio transmission systems, i.e. using radiation field
    • H04B7/02—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas
    • H04B7/10—Polarisation diversity; Directional diversity

Definitions

  • a This invention relates to radio communication systems and has for its object to provide apparatus whereby the effects commonly known' left hand elliptically or circularly polarized, There are theoretical and experimental reasons for supposing that the right hand polarized ray is much more attenuated than the left hand one so that, practically speaking, the latter may be regarded as the surviving reflected ray.
  • the directions of polarization are reversed in the Southern Hemisphere.
  • the direct ray which, in the case of a normal transmitting aerial, such as is used for broadcasting purposes, is vertically polarized.
  • the principle of this invention as applied to a receiving station, consists in picking up energy which has reached the receiving station from the transmitter directly and energy which has reached the said station by reflection by means of a double aerial system which is so arranged and connected with a receiver apparatus proper that the voltages from each aerial of the system and due to the incident right hand (or left hand) circularly or elliptically polarized rays substantially cancel one another, while the voltages due to the directly received raysdo not.
  • a receiving station in accordance with this invention comprises a pair of directional receiving aerials which can be oriented in desired directions, means for adjusting the phase relation between current and voltage induced in said aerials differently for each aerial, and means for combining in a common receiving circuit the energy from the two aerials, the combining means being such that the relative intensities of the signals fed to the common receiving circuits from the two aerials maybe adjusted to a desired ratio.
  • the invention is illustrated in the accompanying drawing which shows, diagrammatically, a portion of a receiver system in accordance with the invention, the said system comprising a pair of mutually perpendicular frame aerials Al, A2 which are mounted as a single structure so as to be rotatable together about a vertical axis VA. Connection to each aerial is made through a pair of slip rings SI or S2 and means are provided for adjusting the phase relation between current and voltage in each aerial separately; for example, an adjustable condenser C! or Cl may be included in each aerial. Connection is taken from one pair Si of slip rings to a radiogoniometer primary R!
  • connection is taken from the other pair S2 of slip rings to the other radiogoniometer primary R2 a search coil SC connected to the receiving apparatus proper (notshown) being associated withthe two primaries as in the ordinary radiogoniometer arrangement.
  • the whole apparatus including the slip rings and radiogoniometer coils is enclosed in a shield box SB.
  • the whole apparatus For reception the whole apparatus is tuned to the desired signal wave, as in the customary manner, and the tuning condenser in one of the aerials is increased in value and that in the other decreased so that the current in one aerial is caused to lag by 45 and that in the other is caused to lead by 45 on the E. M. F.s induced therein.
  • the aerials can be oriented in any direction, but preferably the orientation is such that the direction of the transmitting station bisects the angle between the two aerials, i.
  • any convenient means for phase ad justment of the oscillations other than the mistuning means above described, may be employed.
  • a local oscillation generator is connected to set up voltage in any suitable circuit, such as a potentiometer resistance and means are provided for superimposing voltage from this resistance in the radiogoniometer primary circuits.
  • a potentiometer resistance P across which the local generator is connected to the screen box SB which may be grounded in any suitable manner and the other terminal is connected through a first switch Xi and an inductance Ll to a coil Ml coupled to coils Wi in the circuit of the frame aerial A! which circuit includes, of course, the aerial Al and the associated radiogoniometer primary RI.
  • the last mentioned terminal of the potentiometer resistance P is also connected through a second switch X2, an adjustable condenser 02 and a resistance SR2 all in series to a coil M2 similarly inductively coupled to coils W2, W2 in the circuit of the second frame aerial A2, i. e., the circuit including the said frame aerial A2, and its associated radiogoniometer primary R2.
  • a second switch X2 an adjustable condenser 02 and a resistance SR2 all in series to a coil M2 similarly inductively coupled to coils W2, W2 in the circuit of the second frame aerial A2, i. e., the circuit including the said frame aerial A2, and its associated radiogoniometer primary R2.
  • the phasing condenser e. g.
  • a test of the correctness of the phasing as obtained by adjusting as set out above may be made by means of an auxiliary oscillator (not shown) designed to provide two E. M. F.s in quadrature.
  • an auxiliary oscillator (not shown) designed to provide two E. M. F.s in quadrature.
  • the currents induced in the two aerials will be in quadrature and if the adjustments are such that the said induced currents are equal in amplitude, the search coil can be adjusted so that there is zero E. M. F. set up therein in the +45 position and maximum E. M. F. in the -45 position.
  • the aerials have been correctly phased if it is possible to obtain balance in the +45 position, i. e. with equal coupling of the search coil to the radiogoniometer primaries.
  • the orientation of the two frame aerials is immaterial as regards sense, since there is obvious symmetry about the vertical axis. Unfortunately, it is only in exceptional cases, or where the receiver is quite close to the transmitter that the rays are circularly polarized, elliptical polarization being the general condition. For elliptical polarization the aerials must, of course, be oriented correctly.
  • the resultant reflected signal is elliptically polarized so that it can be regarded vectorially as made up of two magnetic fields which are at right angles to one another, the representing vectors being along the major and minor axes of, the ellipse.
  • the aerials be so oriented that their planes lie along the major and minor axes of the ellipse, then the E. M. F.s induced in the two aerials will be 90 out of phase and a balance as regards the reflected rays will be obtained in some position of the radiogoniometer search coil. The correct position can be found approximately by calculation and then finally set by trial to the correct value.
  • the received signals should be substantially free from fading since only voltages due to the direct rays will be fed to the receiver proper.
  • receivers as above described are practically sensitive only to the direct rays they must be positioned within the direct ray range of the transmitter.
  • a receiver arrangement in accordance with this invention does not eliminate both the right and left hand polarized rays, though it may be adjusted to eliminate either of them.
  • the eifects of fading are eliminated or greatly reduced by the invention by reason of the fact that (at any rate with frequencies in or near the present broadcast frequency band) only one of the reflected rays survives reflection to any substantial extent and reception of this ray can be practically eliminated by the invention.
  • a radio receiving system comprising a pair of mutually perpendicular frame aerials rotatably mounted as a single structure about a vertical axis, a radiogoniometer having a primary coil electrically connected to each of said frame aerials, and a search coil electrically coupled to said primary coil, a plurality of coupling coil elements, said coupling coil elements being electrically in series with said primary coil and to said frame aerials, and capacitive means for adjusting the phase relationship between current and voltage in each frame aerial separately, said means comprising a variable condenser symmetrically arranged at the apex of each frame aerial.
  • a radio receiving system comprising a pair of mutually perpendicular frame aerials rotatably mounted as a single structure about a vertical axis, a shielded box containing a radiogoniometer having a primary coil electrically connected with each of said frame aerials, and a search coil electrically coupled to said primary coil, a plurality of coupling coil elements, said coupling coil elements being electrically connected in series with said primary coil and to said frame aerials, and capacitive means for adjusting the phase relationship between current and voltage in each frame aerial separately, said means comprising a variable condenser symmetrically arranged at the apex of each frame aerial.
  • a radio receiving system comprising a pair 20 of mutually perpendicular frame aerials rotatably mounted as a single structure about a ver tical axis, a shielded box containing a radiogoniometer having a primary coil electrically connected with each of said frame aerials, and a search coil electrically coupled with said primary coil, a plurality of coupling coil elements, said coupling coil elements being electrically connected in series with said primary coil and to said frame aerials, and capacitive means for adjusting the phase relationship between current and voltage in each frame aerial separately, said means comprising a variable condenser symmetrically arranged at the apex of each frame aerial, a resistance connected to said shielded box, the other side of said resistance being connected to two switches, each switch being separately connected in series with each one of said coupling coil elements and said shielded box, and a local oscillator connected across said resistance.

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  • Engineering & Computer Science (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Signal Processing (AREA)
  • Variable-Direction Aerials And Aerial Arrays (AREA)
  • Near-Field Transmission Systems (AREA)
US736586A 1933-07-22 1934-07-23 Radio communication system Expired - Lifetime US2082825A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GB20725/33A GB422929A (en) 1933-07-22 1933-07-22 Improvements in or relating to radio communication systems

Publications (1)

Publication Number Publication Date
US2082825A true US2082825A (en) 1937-06-08

Family

ID=10150621

Family Applications (1)

Application Number Title Priority Date Filing Date
US736586A Expired - Lifetime US2082825A (en) 1933-07-22 1934-07-23 Radio communication system

Country Status (5)

Country Link
US (1) US2082825A (enrdf_load_stackoverflow)
BE (1) BE404169A (enrdf_load_stackoverflow)
DE (1) DE634975C (enrdf_load_stackoverflow)
FR (1) FR775773A (enrdf_load_stackoverflow)
GB (1) GB422929A (enrdf_load_stackoverflow)

Also Published As

Publication number Publication date
GB422929A (en) 1935-01-22
BE404169A (enrdf_load_stackoverflow)
DE634975C (de) 1936-09-07
FR775773A (fr) 1935-01-09

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