FINAL REPORT - Stakeholders - Ofcom

Though the amount of shipping traffic is still growing, this growth is relatively small 15 ; it is
unlikely that in the short- to medium-term congestion in the maritime radar bands will be
experienced. One option is therefore to reduce the amount of spectrum available to
maritime radars and re-use the recovered spectrum for other purposes.
However, the ability to restrict the spectrum allocated to maritime radars is, to a large
extent, hamstrung by the international nature of the traffic. Whilst the UK could impose,
for example, a restriction on the available radar spectrum, it would be very difficult for
radar users entering UK waters to comply with this. Notwithstanding this, there are also
issues with some of the transponders that are used to enhance the visibility of certain
geographical features (as described in the following sections). A unilateral decision by the
UK to reduce available spectrum could, however, significantly reduce the number of radar
emissions in a given part of the spectrum to a degree where it may become possible for
other services to use the spectrum successfully.
Combined with a drive to improve sharing between services, allowing sharing in some of
the spectrum whilst making it clear that that particular portion of a band was not to be
used by UK vessels may offer the best solution for making more effective use of the
spectrum.
4.2.1.8 Possible Overall Spectrum Efficiency Improvements
The operational restrictions placed on maritime radar mean that changes to the
specifications are unlikely to yield a significant improvement in spectral efficiency.
However there does appear to be some potential for a reduction in the amount of
spectrum allocated to maritime radar services, especially if this sharing is confined to one
portion of the band.
4.2.2 RACONs
4.2.2.1 Technology Description
Radar Beacons (RACONs), when used with a ship’s radar form a secondary navigation
system and operate in the 3 and 9 GHz bands.
ITU Radio Regulation 4.40 defines a RACON as: ‘a transmitter receiver device associated
with a fixed navigational mark which, when triggered by a radar, automatically returns a
distinctive signal which can appear on the display of the triggering radar, providing range,
bearing and identification information.’
The displayed response has a length on the radar display corresponding to a few nautical
miles, encoded as a Morse character beginning with a dash for identification. The
inherent delay in the RACON causes the displayed response to appear behind the echo
from the structure on which the racon is mounted.
Racons are used for the following purposes:
• To identify aids to navigation, both seaborne (e.g. buoys) and land-based (e.g.
lighthouses);
• To identify landfall or positions on inconspicuous coastlines;
• To indicate navigable spans under bridges;
15
UK international freight for example grew on average just 2.3% per annum between
1980 and 2000
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