Radar Experence Imput Needed

big foot · 12-01-2003, 06:07 PM

In process of reseaching for a radar unit for a 19 ft boat to be used for bay and near shore use on Vancover Is. Have been leaning toward the Jrc 1000 with the 12 in antenna mainly because of the small dia antenna and the weight. All other units seem to have a 15 or 18 in antenna. Would there be that much difference ? Would appreciate recomendations. Thank you , Bob

Onokai · 12-01-2003, 07:18 PM

I've got a small Furuno unit on my 23 footer. I learned a lot when a furuno tech was aboard tuning it (a whole other story). One of the main things is: the bigger (wider) the array, the more definition your unit shows, especially showing, say straight lines. For example, the marina slips show up somewhat as blobs but if my array was longer, say 24 inches, the slips might be shown as sharp-edged slips. The longer the better. I realize small and light is better for a small craft but get an array that is as wide as you can and still be light. Mark

ONOKAI

Mark Mc · 12-01-2003, 08:28 PM

Bigfoot, when you compare specs you obviously see the listed "range" (i.e. 12 mile, 16, 24, etc). Don't pay too much attention to that. The more important specs are the horizontal beam width and power. If two radars have the same power (say 2 kW) but one has a 4 deg beam vs a 5 deg beam, the 4 deg model will do a better job picking up targets. The narrower the beam, the higher the power density (power per unit area, like mW per square cm) when it hits the target.

This is somewhat the same as what the other Mark posted, because generally speaking the wider the antenna the narrower the beam width. So for a few extra bucks, you might think about moving up to the JRC 1500, or the comparable Furuno, to get a narrower beam. The antenna would probably only be a few more pounds.

Miss B Haven · 12-02-2003, 07:52 AM

The same thing is true for open array vs dome. Same power, diameter = better resolution with an open array. If you have a place to mount it where a turning antenna won't be grabbing things like fishing poles (don't ask me how I know this) then you can get better resolution with a smaller open array. When I bought my Furuno the 2 foot open array 2KW unit had the same range (which as stated is really a measure of resolution) as the 4KW dome (open arrays have a tighter beam).
Couple more things to watch on a small boat. The antenna needs to be mounted high enough so that it will not microwave your eyes or brain. :shocked: If that's not doable you can mount it really low and not worry about birth control after a few trips. :grin:
Another thing is that you need enough charging/battery power to run it. Even a small unit (2KW) takes a lot of juice.

Pitch Pocket · 12-02-2003, 08:25 AM

The horizontal range is very misleading. The radar works on a line of sight basis. If you mount your array 10 feet off the water, it can only 'see' about 4.25 statute miles due to the curvature of the earth. You would have to mount it 300 feet in the air for it to 'see' 24 miles.

To calculate the distance you can see to the horizon you take the square root of the height of your eyes and multiply by 1.17 to get nautical miles or 1.35 to get statute miles.

If you are 6 feet tall standing on the beach, you can see 3.3 miles or about 2.9 nautical miles to the horizon.

It takes a lot of practice to properly interpret radar data when you really need it and it can be critical to your survival. Best to spend a little more and get a unit that gives you the best information possible.

big foot · 12-05-2003, 03:02 PM

Thanks for your imput ! Everyone confirmed what thoughts were going through my mine but was hoping that maybe the smaller antenna might work. However I believe now the larger unit would be better, Thanks

rojo · 12-06-2003, 06:54 AM

Like Steve said, if it is mounted 10 feet in air you can see approx. 4 miles to horizon. But you can make contact with something 8 miles out if it was more than 10 feet off the water...Roger

corrirod · 12-06-2003, 08:31 AM

As is most cases, bigger and more expensive always seems to be better, but don't beat yourself up over it. I have a 20' boat with the Furuno 1622. It works great......when you absolutely need it.

As Pitch said, you really have to spend a lot of time playing with your radar unit in a controlled environment to understand what it will and will not pick up. I took mine out on the river and practiced picking up buoys, pilings, and other boaters to see how they really show up on the radar screen.

Choppy seas make it next to impossible to locate other small boats past about 1-2 miles. On the otherside of the spectrum, on calm flat seas I can pick up seagulls sitting on the water and flying around the boat.

Clarity is nice but to me, a blob is a blob and I don't want to hit it or it to hit me! Just learn how to decipher those BLOBS! :tongue: :grin:

To me it's like sonagram images. I'll be damned if I could see my kid on those for the first few minutes but after I figured out what to look for it was clear as a bell!

Don't tell my wife though cause she still thinks I could see them the whole time! :tongue:

KeyWest · 12-06-2003, 06:45 PM

I have the same as Corrirod - works great when you need it. The key, with any of these units, is to run them when it's clear and daylight so you will know what your looking at when you DO need to use it.

[ 12-06-2003, 07:46 PM: Message edited by: KeyWest ]

SeaJayOR · 12-09-2003, 12:01 PM

I've been asked to find a radar unit for my Dad's boat next summer and have it installed. So far I've seen the Furuno 1622 recommended in this thread. I will shop around using the advice given. I was thinking Englund Marine would be a good place for purchase and install. Any other recommendations for a place to buy and install the radar?

Reelentless · 12-09-2003, 02:42 PM

Rogers Marine in Portland had the best price, not counting online, for the Garmin chartplotter I purchased. I installed it myself, but they will install. Might give them a call.

Pitch Pocket · 12-10-2003, 04:19 PM

Duplication is great, but why Loran? It is good for repeatable positioning in certain areas, but with the scramble turned off of GPS, it is every bit as good or better than Loran. Just curious why?

corrirod · 12-10-2003, 11:06 PM

SeaJay,

The Furuno unit was very simple to install yourself. It's really as simple as just mounting it and plugging in the wires. There are some very simple calibrating things you do but they are written in the manual and not hard to do.

Just FYI.

SlabQuest · 12-10-2003, 11:29 PM

Another factor to consider is the brightness of the display screen. I have a Ratheon SL72. Great unit. Easy to use and no calibration required. But the screen is hard to see in "bright" fog and impossible in sunlight. Fortunately, it is usually pretty dark out when radar is required.

SeaJayOR · 12-10-2003, 11:46 PM

Thanks guys. I've installed a Tigershark Loran on my boat so I should be able to self-install a unit if it's not too difficult to route the wiring (I'm sure the old man wants it to look nice). I do need a unit that will perform well in the fog. The boat already has a GPS, but after an eventfull trip last year (returning in a the fog after dark :shocked: + [img]graemlins/1zhelp.gif[/img] ) we're gonna get radar as well.

8knots · 12-11-2003, 06:28 PM

Couple years ago after extensive research and comparing prices I called with my best quote to the manager at Boaters World. He had to special order the 1832 Furuno, but he easily beat the best price I had found. I have done this on bulk purchases or big ticket items with them a few times.

KrystalFlash · 12-12-2003, 05:34 PM

Ok,
Being an ex U.S. Navy Radar technician and having a sitex radar on my own boat, I would say that you should concentrate on several things. The most important thing I believe would be beam-width. For a given size of antenna, say 2KW, the beamwidth gives higher resolution as the beam narrows. The wider the antenna, the more capable your resolution. As Miss B Haven has stated, the open arrays give higher resolution for a given output power. The position of the antenna is critical. The higher the antenna, the further you can see effectively. Keep in mind that ranges are not exact in most cases at long ranges as L.O.S. is limited due to earth curvature. Sea returns are an additional factor to keep in mind. These are false readings that are returned to the receiver giving a false report due to rough seas. The bottom line is: Mount the antenna as high as is feasible and out of the way of any moving equipment. By far I think the most important thing here is for you to be very familliar with the unit that you have and how to operate it properly. I suggest taking a course on the unit if possible, maybe from the installer if you are going to have it installed. After all, if you have a $10,000 radar on your boat that can see 8 miles, and you don't know how to operate it, it's pretty much just a piece of junk on the boat right?

KrystalFlash
I'd Rather be Lucky than Good
"Quite possibly this is the key to fishing: The ability to see glamour in whatever species one may fish for." - Harold Blasdell; The Philosophical Fisherman

SeaJayOR · 12-12-2003, 11:22 PM

Pitch Pocket,
The Loran is on my boat.
The GPS is on my Dad's. The radar is going on my Dad's boat for another navigational device.
CJ