Annex - Recommendation on Performance Standards for Radar Reflectors

1. Introduction

1.1 Small craft referred to in paragraph 2 of this Recommendation should be fitted with radar reflectors to improve the range and probability of their radar detection.
1.2 Radar reflectors should comply with the minimum performance requirements as specified in this Recommendation.
1.3 In the following paragraphs the echoing areas specified are those for the frequency of 9.3 GHz (corresponding to a wavelength of 3.2 cm).

2. Application

2.1 All vessels of less than 100 tons gross tonnage operating in international waters and adjacent coastal areas should, if practicable, be fitted with a radar reflector.
2.2 The radar reflector should be of an approved type with an adequate polar diagram in azimuth, and an echoing area:
- (i) preferably, of at least 10 m², mounted at a minimum height of 4 m above water level; or
- (ii) if this is not practicable, of at least 40 m², mounted at a minimum height of 2 m above water level.

3. Performance

3.1 Reflectors should be capable of performance around 360° in azimuth using a typical marine navigational radar.
3.2 The echoing areas referred to in paragraph 2 correspond to the maximum values of the main lobes of the polar diagram.
3.3 The azimuthal polar diagram should be such that the response over a total angle of 240° is not less than －6dB with reference to the maxima of the main lobes and that the response should not remain below －6dB over any single angle of more than 10°.

4. Construction

The reflector should be capable of maintaining its reflection performance under the conditions of sea states, vibration, humidity and change of temperature likely to be experienced in the marine environment.

5. Installation

5.1 Fixing arrangements should be provided so that the reflector can be fitted either on a rigid mount or suspended in the rigging.
5.2 If there is a preferred orientation of mounting this should be clearly marked on the reflector. In the case of an octahedral reflector, the correct method of mounting is one corner cavity at the top and one at the bottom. Any other method might reduce its performance below that in 3(c).