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OCEAN ELECTRONIC NAVIGATIONAL AIDS 



Figure 3-4. — PPI scope showing azimuth indication obtained from Ramark station. 



adjustment by relatively untechnical personnel, and with facilities for auto- 

 matic change-over to a spare equipment in event of failure of the operating 

 one. Figure 3-5 shows an X-band (3-cm.) Ramark transmitter. 



Power output requirements are extremely modest; present models radiate 

 about 15 watts on the S-band, and Vz watt on the X-band. Even these low 

 powers will deliver to the navigator's Radar receiver a stronger signal than 

 the best of echoes from its own transmitter. The optimum power output for 

 a Ramark is still somewhat problematical, but it would appear that the final 

 choice will lie somewhere within these limits. A magnetron is used for the 

 S-band 10-cm. RP power source while a standard reflex klystron is used for 

 3-cm. equipment. 



In the development work to date, however, there have been certain prob- 

 lems. One is that of obtaining an equipment of construction sufficiently 

 reliable to permit unattended operation. It is understandable, at this stage 

 of progress in the microwave portion of the frequency spectrum, that this 

 should be true. Solution of this problem would appear to lie simply in the 

 general progress of the techniques in the microwave field. In the meantime 

 the equipment will probably continue to require more technical supervision 

 than might be desirable, but this should grow progressively less. 



No means is provided at present for distinguishing between Ramarks, such 

 as a coded signal characteristic. This is primarily due to the fact that only 

 one or two stations will be operated in a given locality, and therefore these 

 should be readily distinguishable by their relation to other objects. Should 



