Why You Need a
Radar Target Enhancer?
Most yachts and motor cruisers are today made of
GRP, an inherently poor reflector of radar signals,
the prime tool used by ships to see us. For our
own safety and peace of mind we should do all that
we can to enhance our return signal and thus increase
the probability that it will be seen consistently.
The active Radar Target Enhancer is the modern solution
to this problem.
What is a Radar Target Enhancer ?
The Sea-me Radar Target Enhancer is an ACTIVE system
which receives a radar signal, amplifies it and
re-transmits it. This ensures a stronger return
signal and a more even strength around the full
360° azimuth.
Why Fit The Sea-me Radar Target Enhancer?
Your safety depends on being seen, day and night,
fair or foul.
Radar is the prime tool
used by ships to see. In any conditions Sea-me will
increase the probability that you will be seen on
radar.
At night, the range of
the masthead light of a sailing yacht of less than
20m LOA is only 3 nautical miles and of a sailing
yacht of less than 12m LOA only 2 miles. A ship
making 20 knots will cover 3 miles in only 9 minutes
- any steps you can take to give a vessel more time
to avoid you are a must!
Sea-me has a maximum radar
cross section of 63sqm, some 6 times the current
requirement for a passive radar reflector, and an
average of 34sqm.
Sea-me is an ACTIVE system
which emits a stronger signal than it receives.
The detection range is thus increased.
The higher a reflecting
device can be fitted, the better - Sea-me is ultra
light (weighing just 410 gms) and can therefore
be fitted at the masthead.
Sea-me uses little power - just 150mA on standby
and 350mA when it is transmitting.
Sea-me, because it is ACTIVE,
tells you when you are being struck by a radar signal
and therefore when a ship is in your area. A sounder
can be connected to the control box so that you
get an audible as well as a visual warning that
you have been struck by a radar signal.
Sea-me can be fitted to
your boat using a standard 1" 14 thread per
inch antenna mount (not included). Supplied complete
with 24m cable and full instructions, Sea-Me is
easy to fit and to use.
The 5 Benefits
of Sea-Me
The disadvantage of the passive reflector lies in
the many directions in which its radar cross section
is low, resulting in a minimal return.
The polar plot shows that
Sea-me has a much more even response pattern and
suffers from none of the gaps so typical of a passive
device.
1. Greater detection
range.
The strength of a radar signal falls off rapidly
with distance. In the case of a passive reflector
this degradation takes place over a distance equal
to double the range (radar to target and back) whereas
in the case of an active device, which is itself
a transmitter, it only falls off over the return
distance - and from a much higher amplified signal
level. This means that Sea-me, an active device,
has a greater detection range than the typical passive
reflector.
2. A more consistent
return.
Ships today use a system known as ARPA (Automatic
Radar Plotting Aid). This enables the radar to emit
an alarm when it acquires a target within its guard
zones and thus to alert the watchkeeper. Target
acquisition will only take place if the radar receives
returns on at least 50% of scans. Two factors contribute
to a consistent return - the strength of the returned
signal and, because small boats yaw and heel, particularly
in rough seas, the evenness of the return.
3. Better performance
in clutter.
Performance in clutter (rain and wave) is all about
signal strength. The single fact that Sea-me emits
a stronger signal means that it performs better
in clutter.
4. Better performance
at heel.
The effectiveness of a passive reflector falls off
rapidly as the boat heels, as you would expect of
a device which is effectively a mirror reflecting
in a single direction. The Sea-me device shapes
the beam to provide an effective return even when
the boat is heeled.
5. Ship detection
alert.
Passive reflectors cannot give you any warning that
you have been struck by a radar signal indicating
that there is a ship in your area.
Sea-me, being active, knows when it has received
a signal and can alert you with a flashing light,
and if required, audibly. Sea-me thus enables you
to sharpen up your lookout when necessary.