A LONG-RANGE, OCEANOGRAPHIC TELEMETERING SYSTEM 
by ROBERT G. WALDEN 
Woods Hole Oceanographic Institution 
Woods Hole, Massachusetts 
and DAVID H. FRANTZ, Jr., President 
Ocean Research Equipment Company 
Vineyard Haven, Massachusetts 
ABSTRACT 
A low cost transponding buoy for medium 
frequency, long-range ocean telemetry has been 
developed at the Woods Hole Oceanographic 
Institution, and further refined commercially. 
Its use as a drift buoy has been previously 
described; more recently a series of propaga- 
tion tests at 2.4 mc. and 7 mc. has been con- 
ducted out to a 1400 mile range, and tempera- 
ture measurements have been transmitted on a 
regular schedule. The buoy, and associated 
receiving and recording equipment are des- 
cribed, as well as the necessary buoy con- 
trol circuitry for certain typical problems 
in physical oceanography. 
INTRODUCTION 
Almost ten years ago, Henry Stommel 
then of the Woods Hole Oceanographic Insti- 
tution, designed an experiment to study the 
movement of water in the Sargasso Sea near 
the region of Bermuda, and more specifically 
to establish the effect of a given wind on 
the water column to a considerable depth as 
a function of time. The primary tool used 
in this study was a set of radio drift buoys 
designed and built by Hodgson, Parson, Walden 
and Stommel, primarily out of sheet steel, 
plywood, surplus stepping relays and a few 
vacuum tubes, automobile clocks, and, as I 
recall, a rattrap. The rattrap was a vital 
part of a scuttling device which was to sink 
the buoy after a month, to prevent its re- 
maining a menace to navigation. We could 
never bring ourselves to arm the rattrap, 
even though the useful life was considerably 
less than a month. The buoy transmitted on 
schedule a series of tone modulated signals 
representing the output of a number of trans- 
ducers, which included two current meters to 
measure current velocity relative to the buoy 
itself at the surface and at depth, the mo- 
tion of the buoy being determined by daily 
fixes. We obtained the fixes by getting 
bearings with a portable radio direction 
finder mounted on a jeep. Since Bermuda is 
about one sixth the size of Martha's Vineyard, 
the accuracy of the fixes deteriorated 
rapidly with distance from the island. 
tional transducers on the buoy were an 
anemometer, a compass, and later, thermistors. 
Addi- 
50 
The experiment was a success; enough 
of the buoys survived long enough to give a 
valuable insight into the behavior of the 
water mass influenced by wind and of the 
general drift around Bermuda. It also sug- 
gested a host of ways in which similar ex- 
periments could be condycted in the future, 
using radio telemetering buoys. 
If this story were to be presented in 
the classic format, the description of this 
early, crude buoy design would be followed 
by one of more recent developments which 
have enabled us to perform much more sophis- 
ticated experiments working with greater 
quantities of data. We could describe the 
greater reliability of modern oceanographic 
telemetry systems, their greater range and 
longer life. Unfortunately, I am aware of 
no automatic oceanographic data gathering 
system involving more than one or two buoys 
which has produced any more real scientific, 
unclassified data via a radio telemetering 
link than the one operated by Stommel in the 
winter of 1953-4. Nor am I able to explain 
why this is so. It is certainly within the 
state of the art that there be such systems 
in successful operation since by now, most 
components of such a system have: had consider- 
able sea experience. Apparently it has been 
rare until now that the financing, the engi- 
neering talents, and the scientific interest 
have all occurred at the same time. The 
major program coming closest to it is 
Richardson's buoy line to Bermda, and to 
date this has involved recording rather than 
telemetering techniques, and for very adequate 
reasons. 
THEORY OF OPERATION 
The vast extent of oceanic areas has 
required a re-evaluation of our past tele- 
metry schemes. Frequencies in the two to 
three megacycles range are inadequate for 
distances of over a few hundred miles. Trans- 
missions and coding systems such as FM/AM 
quickly become useless due to the signal to 
noise ratios involved. 
