Raymarine radome size

[olavs]

I have recently purchased a Raymarine C80 display for use as a chart plotter and I'm now planning of extending it by interfacing a radar radome. Raymarine Pathfinder radomes come in 2kW(0,125 -48nm) and 4kW(,125 - 72nm) sizes. I think 48nm is more than sufficient for my coastal cruising but wonder if the more powerful one would offer stronger echoes or other benefits.
Thanks for any advice.

<hr width=100% size=1>

 

[sailorman]

my 18 inch is quite acceptable ( radome that is)

<hr width=100% size=1>

 

[Talbot]

Your bio doesnt tell us what your boat is or any other details. The 48nm range is only of any value if you are approaching steep cliffs. You might pick up an American Aircraft Carrier at 24 miles if your scanner is at the top of a raggie mast!
The extra power is of some value in bad weather, but of less value than some of the other gadgets that can be available with the more expensive radars (e.g. north up display, marpa etc.

<hr width=100% size=1>

 

[Oldhand]

The main advantage of the bigger radome is the reduced beam width thus better resolution in azimuth. The extra power is only 3db, not very significant. However, if you are a sailing boat and intend to put it on the mast, think about additional windage and heeling moment as well as battery consumption. Most "average" size sailing vessels make do with the 2kW 18" radome. If you are a mobo, then if you can afford the bigger one, go for it but make sure it is mounted such that it won't radiate on people on the flybridge.

<hr width=100% size=1>

 

[olavs]

Sorry. It's a Sweden Yachts 370 sailing boat. I plan to mount the radome just above the lower spreaders which I guess are approx 6 meters above the water.

<hr width=100% size=1>

 

[Talbot]

I would worry about the extra weight and windage of that much larger radome. I believe the 15-18" radome is about the right compromise for a smaller boat. The power consumption would also be doubled and this is not insignificant on a sailing vessel.

<hr width=100% size=1>

 

[charles_reed]

Radome power

Both are larger than you'll need in a small boat, IMHO.

If a power boat the height above sea-level will be the range-limiting factor, whilst mounted on a sailboat mast the relative movement will make a mockery of reduced bandwidth/ greater accuracy.

In about 40K nm of using a radar coating on a small boat in the last 12 years I've found the 0.125-0.5 ranges the most useful, in fact the only time I use anything more than the 6nm range is when I'm putting up the guard zones to have a spell off watch.

<hr width=100% size=1>

 

[Oldhand]

Re: Radome power

Where did you get the reduced band width from? Larger antennas provide reduced beamwidth which provides higher resolution. Higher resolution has several advantages:

a) Better definition of coastlines
b) Can separate targets which are close together better so less likely to see only 1 taget when there are 2.
c) Provide a "less spread out" echo on which it is easier to take a bearing on the centre of the echo.

Generally if a yacht is sailing without a sea on the quarter, then the mast and boat are in a more stable attitude than than other small boats and thus have the potential for a more stable radar image. I can't understand at all why you find 0.125-0.5 ranges the most useful, to plot shipping at 6 minute intervals to determine course and closest approach in the recognised manner, you need at least 12m range. What do you use your radar for?

<hr width=100% size=1>