|
|
Marine radar review
Garmin GMR 18 HD 4kw Radar with Garmin 3210 chartplotter using Garmin Marine Network for a full featured marine radar electronics package. Garmin on the GMR 18 HD scanner To help you avoid traffic on the water, the GMR 18 HD provides MARPA target tracking when combined with a multi-function display and an optional heading sensor. MARPA tracking allows you to track the bearing, course, speed and predicted closest approach of up to 10 targets. In addition, like all Garmin radars, the GMR 18 HD has self-contained signal processing, which provides you with a more precise, easy to read signature. Connect to the Garmin Marine Network The GMR 18 HD transmits data over the Garmin Marine Network, a 100-megabit plug-and-play proprietary network that gives you the ability to expand your boats system as needed. Once connected to the network, you can use any network-compatible Garmin chartplotter as your radar screen. And as an aid to location awareness, you can overlay the GMR 18 HD digital radar image on the chart plotters map page. You can also split the on-screen display so that you can view the map and the standard radar page simultaneously. Garmin have brought much of the processing within the radar dome, which allows for all the conveniences of radar with your Garmin Marine Networked Plotter and not too much installation hassles. External plug in cables for data and power make installation quick and easy.
Details of this review are courtesy of Tom Schubert who let us look at his yacht a Grand Soleil 47ft. Tom spends lots of time cruising around the east Coast and Caribbean and races as navigator on long distance races. Tom notes that with the present setup of the GMR18 and the Garmin 3210 chartplotter he does not use his PC and Nobeltec software anymore.
Tom told us the gamins HD radar is the best he
has used and he is an ex Merchant marine navigator, so he should know. He
also likes the intuitive soft keys and moving around the Garmin 3210
display
The GMR 18 marine radar priced as low as $1,000 online while the GPSMAP 3210 costs around $1,400 - 1,500. You will need to get a radar mounting unit like the scanstrut and include installation time, but this is a very reasonable radar package. You could use any of the Garmin GPS MAP displays and maybe the 5000 series touch screen is one option. 
When looking at choosing a radar what are the features you
should be looking at?
Beam width for a radar dome like the Garmin GMR18 is around 5 degrees. You can upgrade to the Garmin 24 HD and get 3.6 degrees but at almost double the cost. To get a smaller beam width you need to go to an open array. Open arrays are twice the size of a the GMR18 dome in terms of diameter and can cost 2 or 3 times more money. In this case the 18 inch dome is a good size for this 47ft yacht. BEAMWIDTH, as the name suggests, is the width of the radar beam, and ranges from 7 degrees for the smallest sets down to less that a degree for a large ships set. You can appreciate its significance if you imagine yourself looking for a narrow harbour entrance. If the entrance is to show up as a gap, the radar beam has to pass straight through it with out being reflected from either side. If it is 0.1 wide, for instance, a 1 degree beam will pass straight through when you are 6 miles away, but if the beam width is 6 degrees, you will need to be within a mile before it will show up. The British Marine Electronics Association has provided this information on Radar and beamwidth.
HD (High definition) digital; radar images help define targets and as they are
sharper and more clearly defined. Picking out targets be they land,
buoys, boats markers.
Digital Signal Processing (DSP); is a feature available to digital radar signals and helps with details of the radar image. Digital radars can apply DSP to the return echoes, which preserves the signal strength for better signal to noise ratio (SNR). Check to see if the radar offers DSP as it will increase the clarity of the images. Radar works by line of sight. Marine radars range may be quoted as 36 miles but if your radar is 10 feet above the water and a target is just 15 ft off the water, your actual range will be closer to 9 miles. In most cases you are looking a objects much closer such as local traffic and land masses. One reason to look further will be weather. In most cases, a 4KW system will provide plenty of range for you when you are out at sea. 4KW is a mid range device, and for a larger boat may want to invest in a 6KW system, particularly if you looking for a wider range of sight. MARPA tracking; Because the targets are easily defined you can pick out potential hazards and acquire them as targets and track them with MARPA.
After Installing the boats radar and connecting the radar to the chartplotter, the
Chartplotter should
detect the radar and the
In the case of the Garmin radar scanner installation was easy with only two
plugs to contend with.
Now you can access the radar pages
To get to the radar adjust menu press ADJ/MENU form the soft keys on the
right.
Once in the menu you can access settings for Gain, Sea Clutter, Rain
Clutter, FTC, Zoom, Target Expansions, Trails, Guard Zone, VRM/EBL, MARPA
and hide show navigation features.
Guard Zone can be set and any vessel entering the zone will set of an alarm.
The Garmin GPSMAP 3210 is a full featured chartplotter that costs around
upwards of $1,400 online.
Rings let you know how far targets are away from you, you are the center.
You can position the center in the center of the display or move to the
bottom so you can see more ahead of you.
Mini Automatic Radar Plotting Aid (or MARPA) is a
radar
feature for target tracking and collision avoidance. Targets must be
manually selected, but are then tracked automatically, including
range, bearing, target speed, target direction (course), CPA
(closest point of approach), and TCPA (time of closest point of
approach), safe or dangerous indication, and proximity alarm. MARPA
is a more basic form of ARPA (Automatic
Radar Plotting Aid).
*Garmin suggests the
KVH
1000 heading sensor
for MARPA tracking
MARPA tracking is probably the biggest benefit of a radar system for your
boat. The Garmin allows you to track up to 10 targets and if any of them get
inside your pre set guard Zone an alarm will go off.
this chart radar overlay @ 1/4 nm range with Chart details hidden
The Gamin comes with US charts and Tom only had to by Caribbean and Bermuda
Charts to complete his cruising requirements. He also notes how easy it is
with Garmin to upgrade with a card reader he had to purchase and then
download from the Internet.
The red bar across the top of the screen is
showing a MARPA target inside of alarm range
Top line shows; One radar target acquired showing bearing and distance as well as course and
speed.
You can use this to calculate CPA. (Closest Point of Approach.)
Tracking all vessels in your local waters on your chartplotter is a benefit
of radar and AIS.
One benefit of
Radar and MARPA is that it can pick up all traffic, non commercial as well as commercial
shipping. So if you have good radar fixes, you can see all traffic in your area
show up on your chartplotter, and with the
Garmin HD system, track up to 10 targets. The targets do need manual
acquiring.
AIS is a requirement for all vessels over 300 gross tons according to the
International Marine Organization (IMO) and under Safety Of Life At Sea
(SOLAS) regulations.
AIS is a message sent over VHF
frequencies indicating course, speed, and position of commercial shipping.
As a recreation boater you
can receive this signal with an AIS receiver and have the target
automatically show up on
your chartplotter.
It is similar to MARPA in that you can see a target on your chartplotter,
but with AIS you will get a message on the screen indicating the vessels
name destination and call signs, so you can call them on the VHF radio.
AIS
has the capability to see around a bend also. See diagram in the newsletter
below. This also translates to bad weather. Squalls and rain storms can
produce a lot of clutter on a radar screen, while the AIS plot will still be
clear.
For more information
on AIS read this Newsletter
Both MARPA and AIS have their features and you can have both.
Map and radar overlay
By using the chart radar overlay the less skilled radar reader gets to
understand the blips and targets much easier.
radar at 1/8 miles smallest range
You can see the land masses and anchored boats in the radar image and the
chart radar overlay both at 1/8 mile.
Below split screen
This section provides further reading and information on how to install
radar and how to use and read a Boats Radar display.
Garmin 3210 manual
in PDF form can be found here which includes the radar operation
This seminar covers how radar functions, radar selection, operation of
the radar under various conditions including setting of controls, display
interpretation, basic navigation, and collision avoidance using radar. The
kit includes The Radar Book written by Kevin Monahan ($25 retail)
and Student Notes with copies of slides.
This program features
segments on the basic principles of radar navigation, interpreting radar
displays along with all the features, functions and types of radar
displays available to the boater. Covers radar horizon, displaying
targets, range of bearing, interfacing, echoes and more.
|
|
|
Home | Newsletters | About | FAQ | Contact Us | Site Map
VRM
stands for Variable Range Marker. It is an electronic mark or ring that can
be placed over any target on your radar display. An on-screen digital
readout will let you know the precise range, in nautical miles, between the
target and you
EBL
is the Electronic Bearing Line.
