US1918262A - Ultra-short wave repeating system - Google Patents

Description

A. N. GOLDSMITH Filed April 30, 1932 INVENTOR DP ANA GOLDSM'ITH BY /P A4/VW ATTORNEY ULTRA-SHORT.1 WAVE REPEATING SYSTEM July 18, 1933.

ALFBEDN. eoLnsMITi-r, or

Patented July 18,v 1933 New YORK, N. Y.; Assrenoa fro name oonroas'rron or AIVERICA, A COREOBv-A'EIN OF -DELAXVARE ULTRA-SHORT WAVE Appunti@ mea sp1-i1 3o,

' This' invention relates toV a method of, and

apparatusfor relaying radio signals.

lt is well known that electromagnetic Waves tance. f It is also known that the interposition of objects or the presence of reflecting objects near. or in the path. of transmission affects, to an extent at leash-the ability of a station to receive the radiated energy, and that the condition of the local topography is an important element of consideration in 'ultra-short Wave communication. Y

.Y One arrangement heretofore suggested for transmitting ultra-short Wave signals between-points separatedby a distancegreater 2G I Y than the optical range has been to locate relay or repeater stations at frequent intervalsl along the line of trz'msmissionfor amplifying and reradiating thesignals. lt has been proposed to Yprovide these relay stations With two directive antenn, onefor receiving the signal fro'm'the` station" nearest the translnittingend and the other for reradiating the signal to, the nextadjacent station nearest B the receiving terminal. Such an'arran'gement is described *in lmy copending application 'Serial No. 594,238, filed February Q0, 1932,V and in Va copending application Serial No. 611,769 filed May 17, 1932, bynF'. H. Kroger. The foregoing arrangements referred to are not limited in scope tothe transmission of any one type of radio signal., but may be utilizedtotransmit telegraph signals, television, telephony or other suitable Iforms of modulation.` `When used for the transmission of television, telephone, facsimile, or other broadcasting services for the syndication of programsbetvveen points Widely separated, the repeater stations of these systems are useful not only vas lrelay stations, but, it has been found, may (with suitable arrangements) also bev used as local broadcasting stations Y1n ruraldistricts Where the economics of the situation'do notv otherwisewarrant the erection of television or telephone broadnnrnarrne SYSTEM i lesa serial No. 608,359.

casting stations. For example, a radio trans#v mission line may be used to send programs, such as television, telephone or both, from New York to Chicago. Such line would pass, in part, through rural areas. Due to the fact that the repeater stations are providedvvith highly directional antennae, for reasons of .eii'iciency in operation, these areas 'Would otherwise be beyondA the range of the ultrac Y short Wave broadcasting stations at` the terminals ofthe liner, due to the quasi-optical Y nature ot the electromagnetic Waves used, *andl would not be effectively servedbyfthe intervening highly directional relay stations. VArccording tothe present invention, it is' pro; posed to provide at one or more repeater stationson the transmission line aV non-direc tional (broadcasting) transmitter, in addit1on Ato the directional type. .Accordingly Whatever programs [are passed over the line Vare spread out at right angles to the transmission line as AWell, as lin the direct line of transmission and thus give lservice to a de-4 sired area. y

,Y -More particularly, the present invention comp-rises a radio communication system having .a plurality ofyrepeaterV stations lo. Y

cated between the terminaltransmitting and receiving stations. vEachof these repeaters may comprise a plurality of directionalan tennae which areindividually positioned or arranged to be effective Vin different directrons towards the next adjacent repeater-station.` At any'desir-edv'roneor more of the repeater stations there is` provided a local broadcasting transmitter station Which is ar# ranged to serve ruralareas With broadcasting service eectively. The Wave lengths of the relayrstations and of the associated broadcasting stations are selectedY With due regardA to the corresponding service' to .be rendered.

Y The message signals'for the local' broadcasting .stations may be obtained, in any suitable manner, from the radio transmission linesignals. One Way of eecting this is to demodulate the 'signals passing along the radio transmission lineand use them to control the broadcasting transmitter located at 'the repeater station. The frequency Vofl ntrans- Y f having as greet heights as POSSlble Such as mission from this broadcasting transmitter may be .of any desired value, either the same f an originating station A and a terminal.

station C, between which it is- Adesired to transmit signals. As indicated in the drawing by the direction of the' arrows, station A is arranged to transmit signals and station C to receive signals. intermediate A and C are a plurality of repeater or relay stations R,'R and R. rThese repeaters are each provided with two directional antennas, one of rwhich is adapted to receive sigmounted valongside the transmitting an-y nals land is operative in the direction of the next adjacent-transmitting station and the other of which is adapted to transmit signals in the direction of the neXt adjacent receiving station.Y Since the transmission range of the ultra-short waves depends upony the airline or .visible distance, Y tional to the height above the earths surface, itis proposed to locate all stations'at points mountains, tall buildings, radio masts, etc.

i' The directionalantennae may be ofany suitable type and may or may not use a reflector. A transmitting antenna such as ldeveloped atpresent consists of a copper sheet about 6-X6 on which are mounted insulators for supporting-.a system ofV half wave elements parallel to and one-quarter` wave length away from the copper sheet. The sheet acts as areiiector. On a two-way circuit; i. e., where transmission may Vbe effected in two-directions and wherein automatically reversing signal vrepeaters are Ynot -provided, these antennaswould be mountedy back to back at'the top ofthe repeater'station tower Yand theV receivingY antennas would tbe tennas.' Y Y Y i Y Transmittmg Vstation A is shown as functioningron a yfrequency of 60,000 k. c. ItVK is vto be understood, ofcourse, lthat anyl other utilized. This R on the directiveantenna r, amplified, converted to a new frequency of 59,000 k. c. by beating with a local oscillator of 1,000 k. c. and is then resuitable lfrequency may be radiated onidirective antennaY t at 59,000 k. c.

At repeater Rf the 59,000 k. c.signal is received; on antenna r and is converted to a new frequency of` 58,000 rvk. c., amplifiedL and reradiat'edat 58,000 k. c.fon-transmitting antennal .VvprLilewise, at relay point. R the 58,1000` lz. c'. is received, converted to 60,000

k-SC .ampled endi'l'eradietedv The 60,000

a factor propor- Vmitted at transmitter A. These same three requencies may now be used over again in the same sequence as many times as may be desired. Since the range of these ultra-short wave transmitters is limited to points slightly beyond the distance between the relay points it is impossible for the radiation of the 60,000 k. c. from station C to reach back to repeater R which Vis capable of receiving 60,000 k. c. Y rilhus, by the use of these three frequencies, all possibility of instability is entirely eliminated. Although, the use of three frequencies is preferable in this arrangement and is thought to be the most practical from an operating standpoint, it is to be understood that,if desired, a similar systemutilizing only two frequencies with suitable directive antennas may be employed. Or. anyother suitable system of relay stations may be used such as one'u'tilizing only a single frequency ofthe type described in myV copending application, Serial No. 594,- 238, referred to above. A

VAtrepeater station R local broadcasting station which is obtained from the sion lineV signals; One method of connectinfr the broadcasting station to the radio trans2 mission line would be to deinodulate the signals'passing along the line and to use the resulting energy to control the broadcasting transmitter B located at the repeater station R. -Alternativel sion line signal there is shown a maybe heterodyned with if desired, the transmis- B, the input of radio transmisenergy `usedto obtain a new frequency signal which, with radio frequency power amplification, would permit the broadcasting transmitter to operate. In'the type of system indicated inthe drawing the frequency of transmission from the broadcasting transmitter would, ofcourse, be of anyvdesired value other than the frequency used on the radio transmission line in'order to prevent undesirable feed-back effects.- v However, if the present invention is used with a system of the type described in my copending application, Serial No. 594,238, supra, the frequency may be the same as that used by therelaying station.. An advantage of theV latter arrangement is that should the relaying station associated with the local broadcasting transmitter fail to transmit the transmission line signal the broadcasting signal might be utilized by the next adjacent receiving repeater station;

Transmitter B isarranoed to be an autocasting transmit- Of course,

amazesV :value it 'is desired togive adequate service.

ent that it is susceptible of being modied to meet the dierent conditions encountered in Y its use and it is, therefore, aimed to cover by the appended claims all modifications Within the spirit and scope of the present invention.

I claim: 1. An ultra-short Wave radio communication system off the type comprising a transmitting station, a remote receiving station,

and a plurality of intermediate repeater stations between saidtransmitting and receivingstations,` each of saidrepeater stations v having a directive receiving antenna posi.-VA

tioned to receive signal Waves from its next adjacent station located in the direction of the transmitting station and a" directive transmitting antenna positioned to transmit signal Waves towards its next adjacent sta.-

the receiver, lcharacterized in this, that to at least one of said intermediate receiving staitions there is connected signal transmitting equipment associated with a non-directional antenna for broadcasting purposes, said transmitting equipment being adapted to receive signalsvbeing relayed over said system from station to station. Y

2. An ultra-short Wave radio communication system of 'the type comprising a trans'- mitting station, a remote receiving station, and a plurality of intermediate repeater stations between .fsaid transmitting and receiving stations, each of said repeater stations having a directive receiving antenna pos1 tioned to receive signal Waves from its next adjacent station located in the direction of the 'transmitting station and a directive transmitting antenna positioned to transmit signal Waves toward its next adjacent station located in the approximate direction of the receiver, characterized in this, that to at least one of said intermediate repeater vstations there is connected signal transmitting equipment associated with a non-directional antenna for vbroadcasting purposes, tion located in the approximate'direction of said transmitting equipment being adapted to receive signals of one of the frequencies being relayed over said system and to broadcast sign als on'a dierent frequency.

ALFRED VN. GoLDsMiTa

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