program involving the use of remote buoys 
or ocean stations, if we must count on 
presently available frequencies in the 
electromagnetic communications spectrum. 
The difficulties are complicated by the 
fact that available frequencies are al- 
ready largely allocated and are used al- 
most completely by the military, commer- 
cial and amateur interests. There do not 
appear to be any suitable frequencies for 
extensive reliable communications avail- 
able to the oceanographically-oriented 
research program. 
Anticipating the general problems of 
the oceanographer, the Office of Naval 
Research sponsored a study contract on 
oceanographic telemetry (Contract Nonr- 
3062(00)) with the Convair Division of 
the General Dynamics Corporation. The 
first phase of the study has been com- 
pleted, and an excellent report has been 
submitted to ONR. One of the purposes 
behind the study contract was to inves- 
tigate various factors involved in tele- 
metering data from remote oceanographic 
instrument buoys to shore based facil- 
ities. The factors which must be con- 
sidered in this operation are tremen- 
dously involved and complicated. Some 
of the factors involve the behavior of 
specific radio frequencies in regard to 
radio propagation characteristics, such 
as skip distances, seasonal variations 
of noise with respect to latitude, solar 
induced radio propagation anomalies, 
power requirements, frequency bandwidths, 
etc. All of these variables have now 
been organized and collected together in 
the report submitted to ONR by Convair. 
It appears that long-range communi- 
cation may not be considered reliable 
using whatever frequencies may be avail- 
able between a shore based receiving 
station and remote buoy or ocean station, 
This is assuming that dependable communi- 
cation is required and that data be 
transmitted without objectionable error. 
It is quite true that one may obtain 
occasionally, and even for a limited 
period, transmission which might be con- 
sidered acceptable. The difficulty is, 
however, that such conditions cannot be 
counted upon if reliable transmission is 
required. It is therefore necessary to 
seek modifications of the system whereby 
reliable communications may be estab- 
lished. 
For somewhat over a decade Mr. E.F. 
Corwin, Mr. led. Aliitson and Mr. J.C. 
Appleby of the ee Branch, 
Bureau of Naval Weapons,- and Mr. 
Hakkarinen of the Electronics Branch, 
National Bureau of Standards, have been 
164 
carrying out highly significant work in 
the development of radio telemetering 
ocean buoys and instrument stations. It 
is interesting to note that, as time went 
on, each succeeding buoy design involved 
the use of larger amounts of radiated RF 
power. Later designs tended to evolve 
around the "squirt" techniques and used 
radiated power levels as high as 5kw. 
The "squirt" system combined with 
knowledge gained in 1lonospheric research 
by the Canadian Defence Research Estab- 
lishment may well prove to be valuable. 
The substance of the method developed in- 
volves the use of an interrogation tech- 
nique between the shore based station and 
the remote buoy. In this technique the 
buoy would be equipped with a trans- 
ponder system which would be interrogated 
by means of short pulses on a short duty 
cycle transmitted repetitively by the 
shore based station. When the radio pro- 
pagation conditions are suitable, and the 
interrogation pulse is able to reach the 
buoy, the buoy transponder would send out 
a pulse to the shore station. The re- 
ceived pulse signifies that the communi- 
cations path is for the time being open 
between the two stations. The shore 
based station then would send 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, etc. 
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 four to five minutes. If 
suitable recording and memory systems are 
on board the buoy, it 1s quite practical 
to count on interrogating the buoy at 
some time during a given 24-hour period. 
However, it is quite apparent that one 
cannot establish over a long period of 
time precisely when it will be possible 
to interrogate the buoy, and the memory 
system must take such variables into 
account. 
There is an additional alternative to 
the above-outlined system, which is re- 
commended by the Canadian Defence Re- 
search group, and that is to have avail- 
able a selection of a wide range of radio 
frequencies for such a communication 
system and that the shore based inter- 
rogation 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, i.e., one which can listen simul- 
taneously on all of the expected fre- 
quency bands. However, if such a system 
