Our mast is coming down for new rigging and I finally decided to bite the bullet and add radar. I wanted to add a Raymarine 2KW radome. The yard owner said that he recommends the 4KW unit instead even though I don't need the 48 mile range. He tells me that the higher power unit will give much better close up display. I couldn't find anything on the web about this. The higher power unit does have a narrower horizontal beam which I guess might give more detail. Any radar experts in the crowd? If there is a big difference, I might be swayed to spend the extra $1000 for the 4KW antenna. Bill
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What about height issue?
Bill, I'm looking at a radar installation since my mast is also down this winter. However, the local radar guys say that with a 2kw antenna (which they recommend) on the mast, I will not see the last 100ft. or so around the boat because the mast mount is too high and the beam is too narrow. (This is more important to me in the fog than seeing miles out.) They are recommending a stern pole mount to get a lower and closer view. I'd like to hear other opinions as well.
Bill, I'm looking at a radar installation since my mast is also down this winter. However, the local radar guys say that with a 2kw antenna (which they recommend) on the mast, I will not see the last 100ft. or so around the boat because the mast mount is too high and the beam is too narrow. (This is more important to me in the fog than seeing miles out.) They are recommending a stern pole mount to get a lower and closer view. I'd like to hear other opinions as well.
2KW is Fine
It certainly is true that a 4KW unit will give you better target differentiation. However, do you need it? 2KW is pretty much the standard for sailboats and with good reason. It strikes a good balance on power consumption, antenna weight and size and range. You will find that 8 miles is the max you will normally operate it and it will usually stay in the 2-4 range. One opinion. Rick D.
It certainly is true that a 4KW unit will give you better target differentiation. However, do you need it? 2KW is pretty much the standard for sailboats and with good reason. It strikes a good balance on power consumption, antenna weight and size and range. You will find that 8 miles is the max you will normally operate it and it will usually stay in the 2-4 range. One opinion. Rick D.
Bill, Ricks right. MOST of us don't need the high
power units. We bought a 4kw unit because we went cruising. Here is a story of our experience with it. (I've posted it here before) In my opinion,,, I love our R20X by Raytheon (JRC) It is a 24Mi with the enclosed dome. We bought it in '91 and have used it as our primary form of navigation from Brownsville Washington to Trinidad and back. The antenna is mounted on a radar arch on our Hunter 34, Epitome'. Our unit is jumperd on the motherboard so that it displays the 32 mile range ring. It has the same display and power as the 32 mile model but without the open array antenna. Here is how we use the longer range. We set the range at 12 miles, then use the offset feature to our stern as far aft as it will move us. After the unit displays in offset mode we can increase the range to 24mi and low and behold, we can see ahead to 39.999999mi. That forty mile range is great for finding headlands when off shore or looking for the next 'bend in the road'. That range would not be available if we didn't jumper the motherboard to 32mi. The laws of physics apply with radar so there is little that we sailors can do with these things except select one to work with our personal style. Here is some other stuff I've learned. More important than power or range for close in viewing is 'Horizontal Beam Width'. The lower the number, the better the resolution. Our radar has a HBW of 2.2 degrees. That is much less than those lower powered units with smaller radomes. What that does for us is it lets us see the difference between a tug and a tow. Important in Puget Sound. We also find ourselves dodging DUCKs so factor that in too. And we can see the wake of ski boats and airplanes at low altitude. (as long as they aren't stealth). After a lightning strike off the coast of Panama (us too), our unit was in the shop for repairs. I had taken it to the States for repair but had to buy a Sitex with the same size dome but only 2kw of power. The first thing I noticed was that the buoys marking the channel to the Balboa entrance of the Panama Canal melded into one target before running out of buoys! That was scary enough but what really freaked me out was what we saw, or didn't see the next week in the Caribbean. We were sailing off shore past Isla Provedencia with no intention of visiting. It was a clear afternoon. We were looking at it. GPS said we were 17 miles from the near shore. It is 1700 Feet tall. The radar NEVER SAW IT on 24 mile range, or any range. I called the manufacturer when we reached the states and they had NO solution. The tuner was automatic so it's lack of performance could only be attributed to lack of power. We sold it and took a loss. Fortunately Raytheon was able to affect repair at a reasonable cost. A couple of years later, a idiotic navigational error by the skipper, (me) had us forty miles, or more on the wrong side of Grenada from Trinidad. I had used the wrong compass course for over 12 hours. The GPS was down because of a software defect. They were too expensive to carry a backup then. Besides, who needs GPS in the eastern Caribbean, right? Well at that point, all we had was dead reckoning and Radar. Our DR position plot was also based on a guess of 8 1/2 knots speed and a two knot favorable current. I say 'guess' because our knotmeter was down too. We plotted a course for Granada at sunset. (a friend was with me and we were suppose to pick up my wife at the airport the next afternoon) Of course the island was suppose to be now dead to windward (and 'currentward') We powered up! At 0400 local time, the airport of Grenada appeared at 33mi using the offset feature DIRECTLY OFF THE BOW!. The altitude of that airport is only about 20 feet but there it was! Never, have I felt such a sense of relief. You see, I don't study those dead reckoning 'how to' articles. We might have found the island without radar but I wouldn't have wanted to find out. We drove right in to Prickly Bay and met the flight. When my wife stepped out of Customs I acted like I had been hanging out and waiting for a week, HaH! Sure glad I got rid of that Sitex! Some other things to consider, the US Navy's primary means of navigation is radar. Since Pearl Harbor, no active Navy ship, anywhere, by regulation, is allowed to turn OFF its' radar. Also radar is not DR or even GPS. Those methods place your position in a 'cocked hat'. Your observed position on the radar screen is EXACTLY where you are! OK, these are just my personal experiences and opinions. I COULD BE WRONG! Fred Ficarra Well, there you have it. Again, it just depends. What ever you choose, enjoy. Great tool.
power units. We bought a 4kw unit because we went cruising. Here is a story of our experience with it. (I've posted it here before) In my opinion,,, I love our R20X by Raytheon (JRC) It is a 24Mi with the enclosed dome. We bought it in '91 and have used it as our primary form of navigation from Brownsville Washington to Trinidad and back. The antenna is mounted on a radar arch on our Hunter 34, Epitome'. Our unit is jumperd on the motherboard so that it displays the 32 mile range ring. It has the same display and power as the 32 mile model but without the open array antenna. Here is how we use the longer range. We set the range at 12 miles, then use the offset feature to our stern as far aft as it will move us. After the unit displays in offset mode we can increase the range to 24mi and low and behold, we can see ahead to 39.999999mi. That forty mile range is great for finding headlands when off shore or looking for the next 'bend in the road'. That range would not be available if we didn't jumper the motherboard to 32mi. The laws of physics apply with radar so there is little that we sailors can do with these things except select one to work with our personal style. Here is some other stuff I've learned. More important than power or range for close in viewing is 'Horizontal Beam Width'. The lower the number, the better the resolution. Our radar has a HBW of 2.2 degrees. That is much less than those lower powered units with smaller radomes. What that does for us is it lets us see the difference between a tug and a tow. Important in Puget Sound. We also find ourselves dodging DUCKs so factor that in too. And we can see the wake of ski boats and airplanes at low altitude. (as long as they aren't stealth). After a lightning strike off the coast of Panama (us too), our unit was in the shop for repairs. I had taken it to the States for repair but had to buy a Sitex with the same size dome but only 2kw of power. The first thing I noticed was that the buoys marking the channel to the Balboa entrance of the Panama Canal melded into one target before running out of buoys! That was scary enough but what really freaked me out was what we saw, or didn't see the next week in the Caribbean. We were sailing off shore past Isla Provedencia with no intention of visiting. It was a clear afternoon. We were looking at it. GPS said we were 17 miles from the near shore. It is 1700 Feet tall. The radar NEVER SAW IT on 24 mile range, or any range. I called the manufacturer when we reached the states and they had NO solution. The tuner was automatic so it's lack of performance could only be attributed to lack of power. We sold it and took a loss. Fortunately Raytheon was able to affect repair at a reasonable cost. A couple of years later, a idiotic navigational error by the skipper, (me) had us forty miles, or more on the wrong side of Grenada from Trinidad. I had used the wrong compass course for over 12 hours. The GPS was down because of a software defect. They were too expensive to carry a backup then. Besides, who needs GPS in the eastern Caribbean, right? Well at that point, all we had was dead reckoning and Radar. Our DR position plot was also based on a guess of 8 1/2 knots speed and a two knot favorable current. I say 'guess' because our knotmeter was down too. We plotted a course for Granada at sunset. (a friend was with me and we were suppose to pick up my wife at the airport the next afternoon) Of course the island was suppose to be now dead to windward (and 'currentward') We powered up! At 0400 local time, the airport of Grenada appeared at 33mi using the offset feature DIRECTLY OFF THE BOW!. The altitude of that airport is only about 20 feet but there it was! Never, have I felt such a sense of relief. You see, I don't study those dead reckoning 'how to' articles. We might have found the island without radar but I wouldn't have wanted to find out. We drove right in to Prickly Bay and met the flight. When my wife stepped out of Customs I acted like I had been hanging out and waiting for a week, HaH! Sure glad I got rid of that Sitex! Some other things to consider, the US Navy's primary means of navigation is radar. Since Pearl Harbor, no active Navy ship, anywhere, by regulation, is allowed to turn OFF its' radar. Also radar is not DR or even GPS. Those methods place your position in a 'cocked hat'. Your observed position on the radar screen is EXACTLY where you are! OK, these are just my personal experiences and opinions. I COULD BE WRONG! Fred Ficarra Well, there you have it. Again, it just depends. What ever you choose, enjoy. Great tool.
The Incremental Cost is Worth It
We've got a 2kw and if I had to do it over again I'd spring for the 4kw to get the extra detail. Remember that there are things radar can have difficulty picking up: Cone-shaped buoys without radar reflectors, Wood barges,Boats without radar reflectors, Flat-sloped beaches, etc. If you're going to play in the fog then besides adding the radar reflector so others can see you (realize that the reflector can't be seen through a wet sail so you'd be blind to someone else in that direction) also add an automatic fog horn to generate the required audible signal. If there is ever a "problem" like colliding with another vessel you want to make sure you've done everything correct.
We've got a 2kw and if I had to do it over again I'd spring for the 4kw to get the extra detail. Remember that there are things radar can have difficulty picking up: Cone-shaped buoys without radar reflectors, Wood barges,Boats without radar reflectors, Flat-sloped beaches, etc. If you're going to play in the fog then besides adding the radar reflector so others can see you (realize that the reflector can't be seen through a wet sail so you'd be blind to someone else in that direction) also add an automatic fog horn to generate the required audible signal. If there is ever a "problem" like colliding with another vessel you want to make sure you've done everything correct.
Resolution
Angular resolution (horizontal and vertical) is determined by the physical size of the antenna, not the power - a larger antenna means a greater ability to separate objects that are close together. That said, most low power radars come with small antennas. I guess the manufacturers equate low power with small boats.
Angular resolution (horizontal and vertical) is determined by the physical size of the antenna, not the power - a larger antenna means a greater ability to separate objects that are close together. That said, most low power radars come with small antennas. I guess the manufacturers equate low power with small boats.
Without beating a dead horse,
I would get the 2kw unit and put it high on the mast. Read the archives. There is a lot of discussion on this just a few months ago and my arguments and reasons are there. Pete, all due respect, your local radar guys are wrong. Try going out on someones boat who has one mounted high and compare it to one on a pole then decide for yourself. Seems everybody has a different idea.
I would get the 2kw unit and put it high on the mast. Read the archives. There is a lot of discussion on this just a few months ago and my arguments and reasons are there. Pete, all due respect, your local radar guys are wrong. Try going out on someones boat who has one mounted high and compare it to one on a pole then decide for yourself. Seems everybody has a different idea.
Thanks for the Inputs
After reading some of the posts and some other websites, I have decided to go with the larger unit. I am installing it on the mast which will be down soon because of hurricane damage. A pole on the rear of the boat was an option, but I have too much junk back there now with davits, motor cranes, MOB poles, etc, etc. Thanks to all again, Bill S/V Bella
After reading some of the posts and some other websites, I have decided to go with the larger unit. I am installing it on the mast which will be down soon because of hurricane damage. A pole on the rear of the boat was an option, but I have too much junk back there now with davits, motor cranes, MOB poles, etc, etc. Thanks to all again, Bill S/V Bella
Patrick, I did your test, this summer.
As we motored under the Agate Pass bridge, (steel) I stayed below and watched the radar screen. As an update for our new viewers and folks who don't remember Patricks' test and our conversation, (everybody
) as the steel bridge passed over the antenna, would it still be visible? I said I didn't know for sure but didn't think it would be. Patrick, didn't you say it would be seen? Anyway, as we went under, the bridge target turned from a straight line to a donut over the top of the antenna. The portion of the bridge, (75' clearance, 12' high antenna dome from water line) on either side of the donut, was always visible on the screen. The target was a donut only for about five boat lengths from the bridge and to either side of the antenna. Make sense? We were discussing the ability of an antenna to 'see' close-in. Mine seems to be able to do so, so it would work high on a mast for close-in target detection. Whew! I quit.
As we motored under the Agate Pass bridge, (steel) I stayed below and watched the radar screen. As an update for our new viewers and folks who don't remember Patricks' test and our conversation, (everybody
) as the steel bridge passed over the antenna, would it still be visible? I said I didn't know for sure but didn't think it would be. Patrick, didn't you say it would be seen? Anyway, as we went under, the bridge target turned from a straight line to a donut over the top of the antenna. The portion of the bridge, (75' clearance, 12' high antenna dome from water line) on either side of the donut, was always visible on the screen. The target was a donut only for about five boat lengths from the bridge and to either side of the antenna. Make sense? We were discussing the ability of an antenna to 'see' close-in. Mine seems to be able to do so, so it would work high on a mast for close-in target detection. Whew! I quit.another question
I also am contemplating adding Radar next spring. I also am looking at the 4 kw enclosed raymarine package to network with my existing raymarine instruments. My dock neighbor just installed the same package I am looking at. He said he read in the instructions about screen placement. I had planned on installing the screen on my edison pedistal. by purchasing the bent elbow tube so it would ride high and in easy view. Edison makes this elbow extension or new bar strickly for this purpose and adding other instruments at the helm. However my dock mate said he read in the raymarine instructions that the radar screen had to be at least 3' from the compass, now mounted on our binical pedestal . My installation would place this new radar screen approx 18" away from the compass.... has anyone heard of this???..and can there be a correction in the compus diviation to allow for the radar so close??? thanks Rob
I also am contemplating adding Radar next spring. I also am looking at the 4 kw enclosed raymarine package to network with my existing raymarine instruments. My dock neighbor just installed the same package I am looking at. He said he read in the instructions about screen placement. I had planned on installing the screen on my edison pedistal. by purchasing the bent elbow tube so it would ride high and in easy view. Edison makes this elbow extension or new bar strickly for this purpose and adding other instruments at the helm. However my dock mate said he read in the raymarine instructions that the radar screen had to be at least 3' from the compass, now mounted on our binical pedestal . My installation would place this new radar screen approx 18" away from the compass.... has anyone heard of this???..and can there be a correction in the compus diviation to allow for the radar so close??? thanks Rob
Picture of "Fred's: Agate Pass Bridge
This is a picture of the Agate Pass Bridge that Fred is trying to describe on one of our rare days when it wasn't raining. A lot of people think that S/L on the time sheet stands for Sick Leave but that's not true with everyone. I used it for Sun Leave! As an aside, the bridge is now registered as a Historic Bridge - to keep the state highway department from replacing it with one that has more lanes so everybody can get to the ferry easier. Now if that isn't a cool way to slow down "progress"!
This is a picture of the Agate Pass Bridge that Fred is trying to describe on one of our rare days when it wasn't raining. A lot of people think that S/L on the time sheet stands for Sick Leave but that's not true with everyone. I used it for Sun Leave! As an aside, the bridge is now registered as a Historic Bridge - to keep the state highway department from replacing it with one that has more lanes so everybody can get to the ferry easier. Now if that isn't a cool way to slow down "progress"!
Fred, the donut is a consequence of
the time it takes the unit to switch from transmit to receive. There will be a dead zone which if I am not mistaken will change as you change ranges. Five boat lengths seems like a lot. Fred, did you try viewing the bridge on different ranges?
the time it takes the unit to switch from transmit to receive. There will be a dead zone which if I am not mistaken will change as you change ranges. Five boat lengths seems like a lot. Fred, did you try viewing the bridge on different ranges?
Patrick, no,
We were motoring under the bridge and all that I was looking for was whether or not the bridge would remain visible. I didn't note the range setting nor the donut diameter with any degree of accuracy. All I can say is the channel is about 300 feet wide between the bridge supports and less than that is available for a keel boat at low tide. The donut took at least half of that image under the bridge. The scientific method WAS NOT used. P.S. Patrick, on second thought. What I was looking at was a distorted return image of the bridge. It was a timing problem because the bridge was so far above the correctly timed return wave. The 'donut' that we all should have, was normal. Make sense?
We were motoring under the bridge and all that I was looking for was whether or not the bridge would remain visible. I didn't note the range setting nor the donut diameter with any degree of accuracy. All I can say is the channel is about 300 feet wide between the bridge supports and less than that is available for a keel boat at low tide. The donut took at least half of that image under the bridge. The scientific method WAS NOT used. P.S. Patrick, on second thought. What I was looking at was a distorted return image of the bridge. It was a timing problem because the bridge was so far above the correctly timed return wave. The 'donut' that we all should have, was normal. Make sense?
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