https://declassified.library.utoronto.ca/files/original/eead7602cc64a57db3c41585bb564936.pdf c4ea6a0b05c0ac67fed3b9488f651395 PDF Text Text r= Document disclosed under the Access to Information Act Document divulgue en vertu de la Loi sur l'acces,a I'information y z d cs-~ mm 1250*36 (siga &) / b Bee 63 afttff,.-5 Ti _U 3Ms fip Radio Mnk ^as recommandad a t a -meet-tag i_al« oil 18 Apr &3 (See Annex A to iettev HQS? 125CK36 dated lH_ty'63)« 2» in view of til© st&temtmt a t para. 4 of jrour HQS 1250*36*2 dated 29~$©v 63 ean you suggest an a l t e r n a t l w whichtfott$d-pMvlde a oireuii- of greater reliability:* • • ' . JA Augu Lt Col SigS.2 JAA/2«7i36/tfg t CSCJC: 000116 �Document disclosed under the Access to Information Act Document divulgue en vertu de la Loi sur I'acces a I'information ATJvfc i^&r!- yfcy7:^ E-^'*7i ^ •'J *-w*- J %s£> ««_. '<*E o a r> ^ ts M E M O R A N D U M HQS 1250-36-2 (D Sigs) Xi Nov 63 Sigs 2 Cost Estimate Transatlantic LF Radio Link 1. Reference is made to a Sigs 2 request for estimated of the Canadian terminal for a Canada - Britain LF radio link. ;cost 2. The total capital cost of transmitting and receiving facilities which would be required in Canada is estimated to be $4,754*000. A break down of this total is attached as Annex A. 3. The various factors taken into account in arriving at the cost estimate are covered in attached Annexures B to E. 4. There is some doubt that the LF radio link which you are considering will provide adequate reliability for your purpose. ;'JH Gillett).; Lt Col Sigs 5 fA m. •sstRgna 000117 �Document disclosed under the Access to Information Act Document divulgue en vertu de la Loi sur I'acces a I'information ANNEX A TO HQS 1250-36-2 (D Sigs) Dated Nov 63 COST ESTIMATE Transmitter Station Transmitter 200 KW RF o u t p u t , 40-60 k c / s $1,500,000 Antenna System efficiency 50$, 50 KC 2,500,000 Building, including air conditioning and mechanical equipment 400,000 Primary power equipment, standby diesel, etc 120,000 Miscellaneous test equipment, furnishings, etc 100,000 Land approx, 640 acres @ §200 125,000 $4,745,000 Total Receiver Station Use e x i s t i n g e a s t c o a s t CASS s t a t i o n , or o t h e r s u i t a b l e DND l o c a t i o n . Receiving equipment I 5,000 4,000 Antenna system Total 9,000 Probable Annual C o s t s Power consumption Maintenance S t a f f - 10 @ #6000 Line r e n t a l (FBS Ottawa - EAST COAST) $ 50,000 100,000 60,000 �Document disclosed under the Access to Information Act Document divulgue en vertu de la Loi sur I'acces a I'information ANNEK B TO HQS 1250-36-2 (D S i g s ) Dated Nov 63 GENERAL CONSIDERATION.FOR TRANSATLANTIC LF RADIO COMMUNICATION 1. Qb.ject An estimate is required of the cost of transmitting and receiving facilities to be installed in Canada to. provide a highly reliable radio' communication link to Britain using frequencies in the vicinity of 50 kilocycles. 2. Distance Involved a. East Coast Canada - Britain 4000 kilometers (approx) b. 3« Ottawa - Britain. 5000 kilometers (approx) Receive Signal Level Radio noise level in Britain during afternoon of summer day at 50 kc/s is 10 tiv/m median and less than 40 uv/ni for 90$ of the time, in a 500 cycle bandwidth. The signal intensity at the receive antenna must be greater than 40 uv/m by the signal to noise ratio necessary for the type of . transmission employed. For single channel FSK a signal to noise ratio of 8 db will provide 1% error rate. Using 6 db as an absolute minimum for a workable circuit, the received signal intensity becomes at least 80 uv/m. If a directional receiving antenna such as a Beverage is used, some improvement in signal to noise ratio may be achieved on an east-west circuit, due to discrimination against noise emanating from southerly directions. A gain of 5 times has been measured, which can be considered to correspondingly reduce the required receive signal intensity. However the antenna length at 50 kilocycles is at least 6000 meters which may be impractical. Therefore, as a first estimate, required receive signal intensity = 80 uv/m for daytime reception in Britain. 4. Radiated Power Using the propagation formula established by Espenschied, Austin, etc for transatlantic radio communication at low frequencies, it has been calculated that for 100 kilowatts of radiated power the field intensities at 50 kilocycles at distances of 4000 and 5000 kilometers will be 89 and 42 uv/m respectively during daytime hours. Since the figure of 89 uv/m corresponds well with the required receive signal intensity of 80 uv/m, it is concluded that 100 kilowatts of radiated .power will provide a workable daytime circuit over a distance of. 4000 kilometers. On this basis alone, the transmitter station should be located on the east coast of Canada. /2 �Document disclosed under the Access to Information Act Document divulgue en vertu de la Loi sur I'acces a I'information - 2 - 5. ; Transmitter Pp-wer For 100 kw of radiated power, required transmitter power is given, by Pt = 100 NA where NA = antenna efficiency. Assuming an antenna efficiency of 50$ as a practical value, required transmitter power is 200 kw. It should be noted that these values compare closely to those of the RCN east coast installation where transmitter power at 73 kc/s is 170 kw and antenna efficiency is 60$. 6. Circuit Reliability Published data shows that received signal level over a transatlantic path -will vary as much as + 20 db from the daytime level over the period of one day. The signal is strongest during night hours, compensating for the night time noise increase. During sunset... and perhaps sunrise conditions in the path the signal will fade significantly beloxir the daytime level, whereas atmospheric noise will generally be high. Communications may be impossible during this fade period, which may last as long as one or two hours. Considerably greater power would be necessary to ensure operation during the sunset fade period. Local thunderstorms in the vicinity of the receiving station will cause disruption of reception. Other than the employment of good receiving station design £© minimize the effect of impulse noise and the choice of receive location for low incidence of storms, there is no way of avoiding these disruptions. 7. Discussion One of the problems of LF communications is the provision of sufficient bandwidth. Other than the availability of spectrum space, the most serious restriction on BandvriLdth is antenna selectivity. The bandwidth of the RCN antenna is 400 cps at an operating frequency of 73 kc/s xijhich has proven suitable for a single 60 xvords per minute radio teletype transmission using 85 cycle shift. It is theoretically possible to transmit two 100 word per minute channels using synchronized double frequency shift in this same bandwidth. The estimates and considerations contained herein are based on an antenna of similar construction to that in use by the RCN, and the use of frequency shift transmission with one or two teletype channels. /3 �Document disclosed under the Access to Information Act Document divulgue en vertu de la Loi sur I'acces a I'information - 3 - A wider bandvri-dth antenna can be produced, using for example multiple tuning, but antenna costs would increase greatly. For wider bandwidth transmission a higlf^transmitter power would be necessary to maintain the same signal to noise ratio. Although the older National Bureau of Standards Circular 557has been used to determine radio noise levels, reference to more recent data indicates similar results. The information presented in this estimate should be considered preliminary. The circuit reliability as presented.could be much less than desired and could only be determined more exactly by reasonably long term measurements of transatlantic signal levels and signal to noise ratios at intended receiving sites. This measure should be followed in any event, prior to final selection of system parameters. New developments and other possibilities could have a major effect on the total cost and performance of this form of communication, and should be examined in a more thorough manner if the requirement is substantiated. For example new transmitting antenna design using a ring radiator, transmitter development believed to be in progress supported by the US government, and directive receiving antennas could have significant effects. �Document disclosed under the Access to Information Act Document divulgue en vertu de la Loi sur I'acces a I'information ANNEX C TO HQS 1250-36-2 (D Sigs) Dated Nov 63 Noise Level - UK 50 kc/s Noise Grades: Dec Mar Jun Sep - NBS Circular 557- 2 2 2* 2 Feb May Aug Nov Season Winter Spring Sun-». Fall Time Block • 00000400 04000800 08001200 12001600 I6OO2000 20002400 Noise Level Fam in db above ktb Winter Spring Sum Fall 119 118 120 118 109 106 112 106 107 103 110 106 111 111 114 108 114 113 . 118 113 123 121 122 121 Equiv. vertically polarized ground wave field strength in db re 1 uv/m for a 1 KG bandwidth rms noise at 1 mc/s: 1 uv = 65 db (Fam) For 50 kc/s & 500 cps bandwidth 1 uv = 65 - 20 log .05 + 3 =65-14+40+3 = 94 db <>£ Noise on summer day = 114 - 94 = 20 db above 1 uv/m (Time zone 1200-1600) = 10 uv/m median For 90$ of time noise will be 20 + 12 = 32 db = 40 uv/m 000122 �Document disclosed under the Access to Information Act Document divulgue en vertu de la Loi sur I'acces a I'information ANNEX D'. TO HQS 1250-36-2 (D Sigs) Dated Nov 63 LF Propagation Ref: Espenschied, etc IRE Feb 1926, page 21 Daytime Field Strength on Transatlantic path E = ff 298 x 103 e " -^25g ^,.25 uv/m where P = radiated power in KW D = distance in kilometers /V.= wavelength in kilometers For D = 4000 km P - 1 E = 8.9 f = 50 kc 10 28.2 For D = 5000 km P = 1 E = 4.2 f = 50 kc 10 13.2 A-= 6 km 100 KW 89.2 uv/m 100 KW 42 uv/m See also Craft Lab. Report 158 which closely agrees with above data. Fig 59 from this report is attached; it may be seen that approx 250 watts transmitter power is required for 4000 km distance. �Document disclosed under the Access to Information Act Document divulgue en vertu de la Loi sur I'acces a I'information ANNEX E TO HQS 1250-36-2 (D Sigs) Dated Nov. 63 References; 1. World wide Radio Noise Levels ", National Bureau of Standards Circular 557, Aug 1955- 2. "Median signal power" required for reception ". US Army' Signal Radio Propagation Agency Technical Report No 5, June, 1961. 3. "Transatlantic Radio Telephone" Espenschied etc. PIRE Feb 1926. 4.. "Sky-wave Field Intensity at LF and VLF"., J.A. Pierce, Cr«ft Lab. Technical Report no 158. 5. RCN Transmitting Station, Newport Corners. provided by LCDR R.F. Duston, RCN. Information 000124 �Document disclosed under the Access to Information Act Document divulgue en vertu de la Loi sur I'acces a I'information *v EASTERN U.S. TRANSMISSION FROM THE EAS" 4000 r 10000 kw iOOO < o 10 0 30 40 50 60 70 . 80 IOC- HO FREQUENCY !N KILOCYCLES I'f-cf- 59* Contours. HEc tl;o?a of Fig„ 58 5 for transri^sion over the Atlantis u,:E froa the Easto Contours of constant required power as a function of Frequency and d i s t a n c e , for July and August noise (1951). Power I s t h a t required t o equal t h e RMS noise i n a 400 cps bandwidth a t t he "worst" hour of t h e day. 0001 ET - ------ -U; .1 � Dublin Core The Dublin Core metadata element set is common to all Omeka records, including items, files, and collections. For more information see, http://dublincore.org/documents/dces/. Title A name given to the resource Hydra Dublin Core The Dublin Core metadata element set is common to all Omeka records, including items, files, and collections. For more information see, http://dublincore.org/documents/dces/. Identifier An unambiguous reference to the resource within a given context HY00186 Title A name given to the resource Transatlantic LF Radio Link Date A point or period of time associated with an event in the lifecycle of the resource 12/16/1963 Source A related resource from which the described resource is derived Hydra Communications - Policy, RG24, 1250-36 Vol. 2, Library and Archives Canada (LAC) Creator An entity primarily responsible for making the resource Department of National Defence Rights Information about rights held in and over the resource Canadian Crown Subject The topic of the resource DND, DWS, emergency planning, emergency communications, radio communications Description An account of the resource Report and series of correspondence between Sigs 2 and Sigs 5, pertaining to the testing of a proposed transatlantic LF radio circuit between Canada and the UK. Sigs 5 concludes the total cost of these facilities would be $4,754,000, and that the reliability of the LF radio link is doubtful. Sigs 2 requests an alternative recommendation. Publisher An entity responsible for making the resource available Canada Declassified Type The nature or genre of the resource Text Format The file format, physical medium, or dimensions of the resource PDF Language A language of the resource en