PART III: INSTRUMENTATION 
18. This section identifies the instruments used for monitoring oceano- 
graphic and meteorological conditions and briefly describes their design, op- 
eration, and location. More detailed explanations of the instruments may be 
found in Miller (1980). Equipment used for other types of data collection, 
such as the surveying system, is not generally discussed; however, references 
are provided in Part IV. 
Wave Gages 
Baylor wave staff gages 
19. Two parallel cable inductance wave gages, manufactured by the 
Baylor Company, Houston, Tex., are mounted on the FRF pier: gage 615 
(sta 6+20) and gage 625 (sta 19+00) (Figure 2). These gages are rugged and 
reliable; and they require little maintenance, except to keep tension on the 
cables and remove any material which may cause an electrical short between 
them. They are calibrated prior to installation by placing an electrical 
short between the two cables, at known distances along each, and by noting the 
voltage output. Electronic signal conditioning amplifiers are used to ensure 
that the output signals from the gages are within a O- to 5-V range. Gage 
accuracy is about 1 percent, with a 0.1 percent full scale resolution. These 
gages are susceptible to lightning damage, but protective measures have been 
taken to minimize such occurrences. 
Waverider buoy wave gages 
20. Two Waverider buoy gages (610 and 620) were positioned offshore at 
0.6 and 3 km, respectively, from the monumentation baseline (Figure 2). These 
gages, manufactured by the Datawell Laboratory for Instrumentation, Haarlem, 
The Netherlands, measure the vertical acceleration produced by the passage of 
a wave. The signal is doubly integrated to produce a displacement signal 
which is transmitted by radio to an onshore receiver. The manufacturer states 
that wave amplitudes are correct to within 3 percent of their actual value for 
wave frequencies between 0.0654 and 0.5 Hz (15- to 2-sec wave periods). 
However, calibration curves for buoys used at the FRF indicate that the wave 
heights reported in the results section of this report for wave periods less 
than 15 sec average about 7 percent less than actual values. For wave periods 
15 
