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4KW versus 2.2KW Furuno radar target accuracy?

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4KW versus 2.2KW Furuno radar target accuracy?

Old 10-16-2008, 12:03 PM
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Default 4KW versus 2.2KW Furuno radar target accuracy?

Have decided to add radar to my boat. Am interested in either the furuno 1724C or the 1734C LCD model radars. The 1724C radar has a 2.2KW 18 inch radome and the 1734c has a 24 inch 4KW radome. The 18 inch radome has a radar beam width of 5.2 degree and the 24 inch radome has a 3.9 degree radar beam width .

Understand that on small boat radar applications the big limiting factor for the range of the radar is the height above the water that the radome is mounted. I estimate that on my boat the radome mount will be about 10 feet above the water line and as a result the radar horizon will be approximately 3.5 miles and that is the distance that I should expect to be able to pick up and track small objects on the radar system (example 20 ft boat).

Given that my estimated radar horizon will be about 4 miles seems that with either radar the 2.2KW with a 24 mile range or the 4 KW range of radar with a 36 mile range the limiting factor on picking up small objects in the distance is the radar horizon (3.5 miles) and not the power of the radar unit.

Understand also that the 4kw radar will punch through rainstorms etc better than the 2.2Kw radar.

Question - if at a range of approximately 1.5 miles from my boat, I was tracking an object the size of a 20 foot boat and was taking latitude longitude readings off the object I was tracking -

Would the 4KW radar system give me a significantly greater accuracy on the exact latitude longitude reading of the object I was tracking than if i was tracking the same object with the 2.2 KW radar system ? Even with multiple hits on the object from several locations?

Thanks for your help.

Mark W
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Old 10-16-2008, 12:34 PM
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Default Re: 4KW versus 2.2KW Furuno radar target accuracy?

It is not the power or range advantage the 24" has has over the 18" it is the beam width, the lowee it is the better resolution will be adn the more likely it is to pick out targets form other objects and sea clutter. With my 4' open array I can pick out two piling markers (about 8" diameter) at a 45 degree angle that are 8' apart from a mile away as distict targets; on a friends boat with a 24" dome , they appear as one and on another friends boat with an 18" Raymarine dome they aren't visible until about 1/2 mile, and then only as one blob.
I think the locating of 18" or 24" (lat & long) will be the same as it is based on timing of signals - it is just you may not see the object with the 18" and may on the 24".

Also, unless you are looking at big ships, long range isn't very important as finding a 20' at more than a mile won't do you much good because it will move.
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Old 10-16-2008, 01:07 PM
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Default RE: 4KW versus 2.2KW Furuno radar target accuracy?

LI
thanks for the reply.


I understand not being able to see 8 inch diameter poles at a mile and that small fiberglass boats are not the best radar reflectors, but I was thinking under most conditions I would be able to see a 20ft boat at 1.5 miles. However, based on your experience you are saying in a lot of cases you would not even be able to see a 20ft boat with a 2.2 KW Furuno radar with an 18 inch radome at 1.5 miles? is that correct?
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Old 10-16-2008, 05:43 PM
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Default Re: 4KW versus 2.2KW Furuno radar target accuracy?

LI32 gave you good info. It is hard to answer your question as the variables like sea conditions and reflectivity of the 20' target are critical. Good or ideal situation and you will pick it up. That said you are more likely to pick it up with the 4kW dome. If cost is the determining factor with your choice IMO save your pennies and get the 4kW dome. You want to increase your odds at seeing targets when conditions are less than ideal as that is the time you need it the most.
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Old 10-17-2008, 05:51 AM
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Default Re: 4KW versus 2.2KW Furuno radar target accuracy?

Because of the variables involved, including motion of your boat, weather and quality of target, but mostly sea conditions - 2-3' waves will fully obscure a 20' fiberglass boat at 1 mile for virtually any radar unit, I can't say what you would or would not see at a given time. I will say, that a bigger antenna (which is why big ships have 12' units with a beam width of 0.5 degrees) always do a better job finding and descriminating targets.
If you can afford the 24" unit, I would get it.
Here's where I'll get in trouble - the Furuno 1734c is $3000 - as good as it is, it is still 2003 technology. For $3300, you could get a Garmin 4208 and 24" HD dome - unless you have an auto-pilot, for either you will need a heading sensor - the Garmin unit is $300; the Furuno PG-500 in $575. The Garmin unit comes with charts - the Furuno does not. IMO, the Garmin 4208/HD dome is as good as or better in radar performance as the 1734C; and as a chartplotter it is not even close - the Garmin blows away the Furuno. The $700 extra for a 24" over 18" is well worth it.
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Old 10-17-2008, 06:52 AM
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Default RE: 4KW versus 2.2KW Furuno radar target accuracy?

Sick / LI
thanks again for the replies. I had no idea the furuno unit required a heading sensor. I thought all I needed was a gps antenna added to the 1734c to determine where in the world i was in time and space.

I have the money for a 4KW unit, guess I just question the need to spend extra money for locating the position of targets at 1 NM. For example, while researching radar beamwidths came across the "rule of 1 in 60". Which as I understand the "theory" dictates that the accuracy of a radar at a given range can be determined by multiplying the beamwidth and the range, then dividing by 60. Thus, all things being equal (sea state/atmospheric conditions etc.) let's say I were to detect an object at 1 NM on a 2.2KW radar with a radome that has a 5.2 degree beamwidth. Applying the rule of 1 in 60 the accuracy as to the location of the detected object in space should be + or - 526 Feet approx (5.2 degree beamwidth x 1 NM /60= .086NM or 526 feet). Likewise, using the "rule of 1 in 60" in an example of a 4KW radar and a 24 inch radome with a 3.9 degree beamwidth to detect the same target at 1 NM the accuracy as to the location of the detected object in space should be + or - 394 Feet approx (3.9 degree beamwidth x 1 NM/ 60= .065NM or 394 feet).

realize the above is theory, but am i on the right track regarding radar accuracy between the 4KW and 2.2 KW with respect to being able to locate the position of a detected target at 1 to 1.5 Nautical Miles? In other words, if I detect a radar target at 1.0 nautical mile and I mark the targets position as a lat long on the radar screen using the radar cursor - then I entered the radar (gps feed) generated lat long into a gps on the boat should I expect to be able to go to the exact location of where the target appeared on radar using my gps within a plus or minus 500 feet accuracy or a plus or minus 100 feet accuracy? Would the 4KW give me much greater position accuracy than the 2.2KW all other things being equal at 1 nautical mile?
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Old 10-17-2008, 07:11 AM
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Default Re: 4KW versus 2.2KW Furuno radar target accuracy?

LI32 you have been hanging out in West Marine to much, the Garmin is showroom electronics. Sorry I have been a charter captian for a while and there is no way I would trust garmin in my boat, you can have your bells and whistles I want reliability.


"In addition, Furuno’s NavNet 3D won NMEA Awards in the three major categories; Radar, Navigation and Fish Finding. Furuno took top honors in the Radar Category for the thirty-third consecutive year with the NavNet 3D DRS Ultra Hi-Definition Radar Series. In the Navigation Category, Furuno took home the NMEA award for the NavNet 3D MFD12. The DFF1, NavNet 3D’s Network Sounder, received the award for Best Fish Finder for the 37th year in a row, according to the company. "



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Old 10-17-2008, 08:25 AM
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Default Re: 4KW versus 2.2KW Furuno radar target accuracy?

Chris,
It's "charter capt's" like yourself I find that have the LEAST amount of knowlege when it comes to marine electroncs. And I mean this with no disrespect. You can teach me how to fish ANY day of the week, but I bet I can take ALL of your electronics knowledge, and drop it in the bucket. The reason, your going on "old" knowelge/experience.

I can tell ya, I have now used the Garmin 24" HD radar for a season, and have compared it closely with both Raymarine and Furuno arrays. When I rigged my new boat this past spring, I wasn't sure what I was going to go with (array or a dome, and which model). The Garmin HD unit has the clearest picture of all of them, and at clsoe range (within a mile), picks out targets (small pots, poles....) better than the rest. I can NOT tell you how they compare at longer ranges, I only looked at close ranges at 1 mile or less. I'm sure the arrays work much better at longer ranges, but for most people what is important is what is close. For you, that is probably different cause your looking for birds way out while offshore fishing and trying to make your customers happy(aka on fish).... But most people use them for navigation in fog and at night.

As for reliabilty, I have had all kinds of brand, and none of them have ever died on me. Reliability is just not an issue in this day and age. From my standpoint, the Garmin products are are actually more reliable than the others. Simply because they suppor thier products, and I can't say the same for Raymarine or Furuno (who now has 1 person in the entire support dept apparently). Garmin on the hand, has 1000's and are constantly updating their software with new features requested by us users. THAT, is reliabilty today.

Lastly, forget the NMA awards. That's like saying hey won the J.D. Edwards awards. Please!!
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Old 10-17-2008, 10:49 AM
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Default Re: 4KW versus 2.2KW Furuno radar target accuracy?

Birdman - 10/17/2008 9:25 AM I can tell ya, I have now used the Garmin 24" HD radar for a season, and have compared it closely with both Raymarine and Furuno arrays. When I rigged my new boat this past spring, I wasn't sure what I was going to go with (array or a dome, and which model). The Garmin HD unit has the clearest picture of all of them, and at clsoe range (within a mile), picks out targets (small pots, poles....) better than the rest.
All the new "HD" radars appear to have clearer pictures because the auto-tuning and filters require much less skill and experience to use. I agree with you that Garmin makes very good equipment that is just as reliable in recreational service as Furuno. In fact, I have two of the new Furuno NavNet 3 MFD 12 displays and they were very unreliable at first due to all the software issues (how about sponaneously rebooting in fog and reorienting the radar display 15 degrees off for "legendary Furuno reliability&quot. It was quite a shock because my earlier Furuno equipment was utterly dependable. Now it works very well but it took two software updates.

That being said, I doubt you could have spent much if any time on the water with a new Furuno "UHD" radar since the displays were only available in late summer. I have a 6kW 4 foot open array and it is nothing short of amazing. I was getting confused when I first used it because it picks up birds sitting on the water at pretty good distances in calm seas. Your Garmin dome just can't produce the target resolution of a big open array no matter how much signal processing is done. I am not saying it isn't good, or even good enough for most people, just that it is ridiculous to assert that a small dome will paint a better picture than an open array at any range, close or distant if both have been tuned properly.
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Old 10-17-2008, 02:50 PM
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Default RE: 4KW versus 2.2KW Furuno radar target accuracy?

if I detect a radar target at 1.0 nautical mile and I mark the targets position as a lat long on the radar screen using the radar cursor - then I entered the radar (gps feed) generated lat long into a gps on the boat should I expect to be able to go to the exact location of where the target appeared on radar using my gps within a plus or minus 500 feet accuracy or a plus or minus 100 feet accuracy? Would the 4KW give me much greater position accuracy than the 2.2KW all other things being equal at 1 nautical mile?
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Old 10-17-2008, 04:52 PM
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Default RE: 4KW versus 2.2KW Furuno radar target accuracy?

markw4321 - 10/17/2008 2:50 PM if I detect a radar target at 1.0 nautical mile and I mark the targets position as a lat long on the radar screen using the radar cursor - then I entered the radar (gps feed) generated lat long into a gps on the boat should I expect to be able to go to the exact location of where the target appeared on radar using my gps within a plus or minus 500 feet accuracy or a plus or minus 100 feet accuracy? Would the 4KW give me much greater position accuracy than the 2.2KW all other things being equal at 1 nautical mile? Mark W
I have never tested the specific accuracy of radar returns to the degree of 100' @ 1 mile but I would bet that the 2.2kW and 4kW antennas would be very close to equal in that respect. The issue is you cannot track a target that the radar does not see.
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Old 10-17-2008, 05:51 PM
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Default RE: 4KW versus 2.2KW Furuno radar target accuracy?

My guess would be the accuracy at one mile would be very close, however, you will pick up more targets with the 4KW.

This summer I traded my old Furuno 2.2KW 18" dome for the new Furuno HD4KW 24" dome. It does punch through the rain and also the fog much much better. The improvement is very noticeable, however, I do not know how much of the improvement is from the increased KW and tighter beam width vs the new HD system.

The new HD radar system is off the charts fantastic. It is very easy to set up and run in changing weather conditions.
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Old 10-18-2008, 06:24 AM
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Default RE: 4KW versus 2.2KW Furuno radar target accuracy?

can anyone comment on the accuracy of a 4kw or 2kw radar with respect to picking off the exact lat long of a target 1 NM away?
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Old 10-18-2008, 06:46 AM
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Default RE: 4KW versus 2.2KW Furuno radar target accuracy?

markw4321 - 10/18/2008 9:24 AM

can anyone comment on the accuracy of a 4kw or 2kw radar with respect to picking off the exact lat long of a target 1 NM away?
Mark W
Mark-
All things being equal the "accuracy" will be the same. The larger dome having a narrower horizontal beamwidth will give you better target seperation when 2 targets are close to each other and the greater power will allow for better distance as well. But the Lat/Lon accuracy should be the same.
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Old 10-18-2008, 08:19 AM
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Default RE: 4KW versus 2.2KW Furuno radar target accuracy?

I have the 1834C and it didn't 'require' the heading sensor. I did install it later to be able to use the chart overlay feature with the radar and it was money well spent. Not sure if it is required to steal numbers, err, I mean acquire targets (GPS coordinates)with the radar. I could do it but never have.[img]../images/emoticons/nono.gif[/img]They are also useful for locating birds, the 4KW will work a little better than the 2KW.

Or you could just call the guy on the radio and ask him to give the numbers. [img]../images/emoticons/biggrin.gif[/img]
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Old 10-18-2008, 10:15 AM
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Default Re: 4KW versus 2.2KW Furuno radar target accuracy?

Mark, why would you care if it is accurate to within a couple of hundred feet at 1 mile? Why not just run to the target. I'm sure the accuracy of the position will improve as you get closer and closer to the target. Just curious as to why that kind of position accuracy would matter.
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Old 10-18-2008, 10:40 AM
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Default RE: 4KW versus 2.2KW Furuno radar target accuracy?

jb2

I am running an import business and when my drop boat comes in at night with the package and I mark him on radar, I want to be able to return to the lat long later and pick up the package. thanks for your interest.

No really I spent $1000 over the past year permitting and placing legal reefs in the gulf only to have guys running radar on their boat tell me trying to keep the numbers secret is useless because he would zap me on radar for the fishing spot. My questions stem from those discussions. From what I can discern from the physics and capabilites of a basic small boat radar anybody outside a mile would have to be fairly lucky to find a small reef site on the bottom without a fairly extensive search of the area. I always move off the spots when I see a boat within a mile.
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Old 10-18-2008, 01:22 PM
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Default Re: 4KW versus 2.2KW Furuno radar target accuracy?

"In addition, Furuno’s NavNet 3D won NMEA Awards in the three major categories; Radar, Navigation and Fish Finding. Furuno took top honors in the Radar Category for the thirty-third consecutive year with the NavNet 3D DRS Ultra Hi-Definition Radar Series. In the Navigation Category, Furuno took home the NMEA award for the NavNet 3D MFD12. The DFF1, NavNet 3D’s Network Sounder, received the award for Best Fish Finder for the 37th year in a row, according to the company. "

Chris, that just means Furuno paid them the most.

I have been on lots of boats with all brands of gear (Raymarine, Northstar, Simrad, Furuno, Lowrance and Garmin). One of my boats has Garmin 4200 equipment (4208 and 24" dome) and the other runs Furuno Navnet2 (1953C (6kw 4' open) + BBFF1); I also fish a lot on a friends boat with twin Garmin 4212's, GSD 22, XM weather and a 6' open antenna. I will tell you first hand the radar performance on the Gramin is as good as my Furuno and the chartpoltter is much better. If you compare Garmin 4200 to Navnet 3d, Garmin is 40+% cheaper. Furuno is going to have to work damn hard this winter at the variuos shows to prove to me the Navnet3d system (2-MFD 12's, 6kw radar, DFF1, Sirius weather) is worth a $5,500 premium over the Garmin 4200. I have zero brand alliance when it comes to products - I want the best value for my hard earned dollars.
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Old 10-18-2008, 02:25 PM
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Default Re: 4KW versus 2.2KW Furuno radar target accuracy?

I wouldn't touch that! That's a good one!

Now the question makes sense. What size is your boat? A 20'er (since you asked about that size)? I think the answer to your question depends at least somewhat on the size of your vessel. I assume it's a typical fiberglass boat?

IMHO, anyone with a decent radar can mark you well outside of a mile if you have a decent size boat. Then they can run to that mark and with a little bit of trolling around, could find your reefs. They can't go right to the reef, but if they don't mind spending a few minutes trolling around, they could find it without too much trouble. They're going to be within a fairly small area if they have either of the 100' or 500' variances you mention. That's assuming they wanted to go to the trouble of doing so. Guess I'm saying I think the guys you're talking to are right. They can find it if they put forth a little effort to do so. I agree with cravenMH that it can be done even with a small radar as far as accuracy is concerned. It's going to be a very small differnce, if any at all.

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Old 10-18-2008, 03:21 PM
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Default Re: 4KW versus 2.2KW Furuno radar target accuracy?

LI, agree with you. Even IF Furuno is a little better than Garmin, no way it's $5500 better. I have Furuno chartplotter and FF on my boat now, along with Furuno RD-30 and GP-31 too. But I'm thinking real hard about the Garmin 4210 with GDL30A. Then add the HD radar overlay next season. I just don't think you can beat it for the money. I will probably keep the Furuno FF though.
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