Radar reflector location

I did a search on the subject already. I have done a lot of reading on radar reflectors and realize the debate of their usefulness is like the anchor debate. I view it as a can't hurt item.

My question is...

Has anyone located a radar reflector in the forward area of the flybridge? I have quite a bit of space that isn't being used. I don't want to put any weight up there for the obvious reasons. It seems like it would be a good location.

The follow on question for anyone that has one up there, do you get any return or interference from your own radar?

If the radar transmission beam doesn't hit the reflector it shouldn't cause any problems no matter where it is. They are typically mounted high so they can be seen by radar units farther away from the boat.

Marin said:

If the radar transmission beam doesn't hit the reflector it shouldn't cause any problems no matter where it is. They are typically mounted high so they can be seen by radar units farther away from the boat.

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Thanks for the answer.

I understand all that. I was hoping to hear from someone who has the installation in the flybridge.

Radar beams do a pretty good job of seing through fiberglass. That's why on many powerboats their best radar reflector is the engine(s) if at least part of it /them is above them waterline. From your avatar your radar antenna is a long ways above the flying bridge structure. Bif you don't get any interference from your power controls, instrumentation, flying bridge enclosure framng, etc you wont from a radar reflector mounted under the console somewhere. It's just another passive piece of metal.

As a single data point a friend has a lobsterboat with the radome mounted on the mast. He has a reflector on one of the mast stays. It used to be attached so it was just below the radome where it caused no interference to the radar display. Over time the clamps have loosened and the reflector has slid down the stay to be just off the cabin roof. He hasn't bothered to raise it back up, and in that lower position it still causes no interference to the radar returns.

alright...that makes sense. My mast is full of gear and was looking at other locations to place a reflector. Has anyone place a Morbi type reflector directly on top of the radome?

Patrick,

I would think as high as possible but out of the radar beam would be best. How about suspended below the radar on your radar mast? No chance of catching the bottom of a radar beam there like you might forward on the FB.

Your vessel probably already has a pretty good radar signature. Have you asked a boating buddy to take a picture of his radar for you to see the radar return yourself? I was surprised at how well power vessels typically appear compared to sailboats. Maybe it's the engines or the large profile, but they are prominent on my radar.

Up under the flybridge fairing is fine...make sure it is in the catch rain position for best reflection....that is more important than a few feet higher...


and remember most radar scanners are behind some thin fiberglass that they are encased in.

This is about the only one worth buying:

EchoMaster by Davis

Just be sure to mount it as high as possible and in the correct "catch rain" position.

Of course just having your radar on increases your radar signature to other vessels. So you may be wasting your money on a reflector.

Paint it black and it'll double as an anchor ball.

FlyWright said:

Paint it black and it'll double as an anchor ball.

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But what about when one is underway? You don't fly your anchor ball underway, do ya?

Trust this vessel displays its day shape in the vertical position when fishing:

Hide it under a fairing like I suggested...for metal boats like yours...not needed to be out in the open anyway.

Metal boat? Don't see the need for installing a radar reflector. My metal boat shows up good without one.

markpierce said:

But what about when one is underway? You don't fly your anchor ball underway, do ya?

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Simple! When underway, it's a radar reflector. When anchored, it's an anchor ball.

Here is an interesting study...

http://www.ussailing.org/wp-content...ore/SAS Studies/2007 Radar Reflector Test.pdf

In my opinion, the hull and superstructure shape, size and height as well as vessel orientation are more influential on the intensity of a radar return than a radar reflector. Sail boats with their sails down produce a poor return for the size of the vessel--much better when abeam of you and the sails up.

One of the better radar returns I've seen from a "trawler type vessel" for the size is the American Tug--there's a lot of flat superstructure returning a radar signal.

The best position for a radar reflector is high on the mast.


Jim
Sent from my iPad using Trawler Forum

Capt.Bill11 said:

This is about the only one worth buying:

EchoMaster by Davis

Just be sure to mount it as high as possible and in the correct "catch rain" position.

Of course just having your radar on increases your radar signature to other vessels. So you may be wasting your money on a reflector.

Click to expand...

Not according to this study:

http://www.ussailing.org/wp-content...ore/SAS Studies/2007 Radar Reflector Test.pdf

"The Davis Echomaster has a reasonable peak and average RCS but is too small to meet the performance requirements of ISO 8729[1]."


Jim
Sent from my iPad using Trawler Forum

I don't recall albin making metal boats...

Size counts , having flown SAR the best radar reflector seems to be the WWII Navy surplus units that unfold.

Sure you toss it after a season , but the coat is minor.

IF I ever put out a May Day , I would break out 3 or 4 and mount them and save one or two for the raft.

OK, I'm going to ask a question that should stir things up a bit. You all are suggesting mounting it in a location that's not in line with the radar beam. That makes sense because you don't want it to interfere with the transmitted beam.


But what about if you mount it in a position where it might distort the minute portion of the transmitted beam that is reflected back to the receiver portion of the antenna. Could that reflected beam be distorted enough by the position of the ball that it could throw off your radar display?


Just curious.

It explains interference in the owners manual pretty well...but a good mounting location of the radar should avoid this issue otherwise radar would be useless on metal vessels.

So it would be pretty hard to mount it someplace to cause that interference unless you tried...turn on you radar and move the reflector around till satisfied.

What about mounting a Morbi M3 or M4 on top of your radome?

JDCAVE said:

Not according to this study:

http://www.ussailing.org/wp-content...ore/SAS Studies/2007 Radar Reflector Test.pdf

"The Davis Echomaster has a reasonable peak and average RCS but is too small to meet the performance requirements of ISO 8729[1]."


Jim
Sent from my iPad using Trawler Forum

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It's done well in past tests. But I don't believe they were trying to meet ISO 8729 standards. Plus it's very well priced.

mount it on top of your own radar.

Mine is in the flybridge fairing, for all the reasons the OP cited. On my previous boat, a 28' express cruiser, I hung it from the arch when needed. Other boats said I made a strong echo with that setup.

On this boat, it's up higher and sits in the "catch rain" position, so it should be even better. I know before I had AIS other vessels could see me over a mile away.

I bought the diamond-shaped reflector at a local commercial fishing supply store. Not pretty, but they must work or those guys wouldn't buy them.

It would be fun to do some comparison tests, with the reflector high, then low. But as it is, I can see & be seen so I'm leaving well enough alone.

I have a Davis (the foldable round kind) mounted in the "catch rain" position on the mast under just under the Radome support. Haven't painted it black yet but have thought about it.

I have a Davis reflector located under one of the flybridge seats.
Before you say that isn't good, I'll tell a short tale.
Several years ago two marina mates passed me as we were headed thru Gardner's Bay. They were side by side. One
had his Davis mounted on one of his flybridge enclosure supports. The other was an experess cruiser and his was under his seat as he did not get around to mounting his.
They both showed the identical large square on my 1.5 kw radar screen. They were approx. 3 miles away when I lost both signals as they turned into Coecles Harbor.
My boating buddy said my boat prints as well as any other on his screen.
I'm keeping mine where it's at.

The only true test would have been to have your buddies fold them up and then see if the return blip got smaller or changed shape.

Capt.Bill11 said:

Of course just having your radar on increases your radar signature to other vessels. So you may be wasting your money on a reflector.

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Please explain. I would think another boat would "see" my boat's radar signal only if when my antenna is pointed exactly at their antenna, their antenna happens to be pointed exactly (or at least within a couple degrees) at my antenna. I would think the chances of that are about 2 in 360.

MYTraveler said:

Please explain. I would think another boat would "see" my boat's radar signal only if when my antenna is pointed exactly at their antenna, their antenna happens to be pointed exactly (or at least within a couple degrees) at my antenna. I would think the chances of that are about 2 in 360.

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The the blip size may change from rotation to rotation but it can give you a better return. And make the vessel easier to seen on the screen.

Much like the difference you may see in returns from a weak signal and a strong one as they move up and down in a large see.

Why not get AIS and forget the radar reflector?

Donsan said:

Why not get AIS and forget the radar reflector?

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The radar reflector isn't for us. It's for another vessel with radar (not necessarily with AIS themselves) to see us. Most boats don't have AIS.