MARINE SCIENCE 107 
strenuous effort to obtain proper frequency allocations or time alloca- 
tions on the communications types of satellites, it is quite certain that 
none will be available when needed at some future date. It is almost 
impossible to overemphasive the amount of pressure being brought 
to bear to obtain communications frequencies in the satellite programs. 
Since the groups interested in collecting data from the ocean are not 
presently represented in any way on the committees and boards making 
such studies, it is imperative that some steps be taken along this line 
as soon as possible. 
There is another possible system, which has recently come to my 
attention that may offer possibilities for reliable communication with 
remote buoy stations. This is a technique that has been explored ex- 
tensively by the Canadian Defense Research Establishment. The sub- 
stance of the method developed involves the use of an interrogation 
technique between the shore-based station and the remote buoy. In 
this technique the buoy is equipped with a transponder system which 
is interrogated by means of short pulses on a short duty cycle trans- 
mitted repetitively by the shore-based station. When the radio propa- 
gation conditions are suitable, and the interrogation pulse is enabled 
to reach the buoy, the buoy transponder sends out a pulse which is re- 
ceived by the shore station. This signifies that the communications 
path is for the time being open between the two stations. The shore- 
based station then sends a coded request to the buoy to transmit its 
stored information. When this cycle is completed, the shore-based 
station then seeks to interrogate another buoy, and so forth. 
This particular system is based upon the fact that when a given 
transmission channel becomes open between two stations it may be 
expected to remain open for a period of from 4 to 5 minutes. If 
suitable recording and memory systems are on board the buoy, it is 
quite practical to count on interrogating the buoy at some time during 
a given 25-hour period. However, it is apparent that one cannot es- 
tablish over a long period of time precisely when it will be possible to 
interrogate the buoy, thus the memory system must take such variables 
into account. 
There is an additional alternative to the above-outlined system, 
which is recommended by the Canadian defense research group, and 
that is to have available a selection of a wide range of radiofrequencies 
for such a communication system and that the shore-based interroga- 
tion system transmit an interrogation pulse in sequence through the 
different, assigned frequency bands. This means, of course, that the 
remote buoy must have a somewhat more sophisticated receiving 
system; that is, one which can listen simultaneously on all of the ex- 
pected frequency bands. However, if such a system is used, the 
assurance of being able to effect communication with the remote sta- 
tion when desired is tremendously improved. 
This latter method is the method which apparently receives the 
most favorable recommendation by the Canadian group. One point 
should be made clear, however, if such a system were used it would 
require a considerable change in the basis of the present assignment 
of radio frequencies to a given activity, since this involves the use 
of a wide range of frequencies and this is not now the common prac- 
tice as far as licensing by the FCC is concerned ; thus certain changes 
would have to be sought in this regard. One might well ask questions 
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