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Since the mean currents within mast of the r dar coverage zone arr weak (0 20
cmls, Petrie and Anderson 14811, and since the surf- Bow in the autumn storm sea-
son is generally dominated by directly luind-driwn currents, the bum were deployed
in the centre of the -rage zone along the broadside look diretion of the riuiar
(120DT). at ranges of 75, 125 and 175 Irm. Unfortunately. a tropieal stonn stalled
over the Grand Bank shortly after deployment and its steady northeasterly winds
quickly dmve the inner two buoys towards the edge of the radar emage. Buoy 1.
deployed at a range of 75 km, stayed within view fewer than 5 days and returned
only 6 radial velocity intercomparisons; Buoy 2, deployed st 125 h, survived for 12
days and provided 23 mmparisons; fortunately Buoy 3, deployed at 175 km, remained
within range for mmt of the experiment and yielded 48 useful comparisons.
3.3 The Radar Component
3.3.1 Radar System
The radar sptem, designed, owned and operated by NRSL, is located on a 2.5 km
strip of land along the mast at Cape Race, as s hm in Figure 3.3.
The HF GWR site eonnistn of receive and transrmt antennas, a receive/mntral
and acmmodations building, and a transmit building The transmit antenna is a
log-periodic dipole array antenna with a half-power beamwidth of 120'(over perfect
ground), a peak power ratlng of 10 KW, and an average power of appmdmately
1 KW. The transmitted waveform is a frequency modulated interrupted continous
wave (FMICW) where the carrier is swept owr 375 kHz to obtaio a range reolution
of approximately 400 m. An operating frequency range bet- 5 and 8 MHz
adable, but the two frequencies used in this experiment were 6.25 and 6.95 MHz.
A blockdiagram ofthesystem architectwe is shovn in Figure 3.4. The &element
phased array IS partitioned into ten Celement subarrays which eao be electronically
phd, via analog beamforming units, to form a subarray pattern. Insteed of the