RADAR reflectors

[Wandering Sagebrush]

I don't know how effective they are, but I wanted one and never bought because i felt the price was too much for what is there.

While poking around my favorite toy store (Fisherman's Marine) in Oregon City, I found a couple of Seadog reflectors for $11.50. The original price was around $30ish. Comparable in WM is $50ish. They are solid aluminum and will break down. There's one left in Oregon City, and maybe some at the Delta Park store.

Steve

[matt_unique]

I have always placed a high priority on radar reflection. I use a medium size tri-lens radar reflector. I have not used other reflection systems, but I know this one works like a champ. It is AMAZING how small of a target even a 30' fiberglass vessel can return for example.

Here is a link for reference, I use the middle size unit:

http://www.tri-lens.com/trilensweb12002002.htm

[drjohn71a]

I have one of the mid-sized, aluminum ball types that comes apart. When out in the ocean, I hang it inside the radar arc, but have kept it in the back of the aft dinette cabinet here on the lake. To my surprise, my dockmates say they can see a large echo of my boat for it's size, even with the reflector tucked away.

John

[20dauntless]

I've heard that having your radar on increases your target size dramatically. Anyone know if this is true?

[colobear]

I wanted a radar reflector but was put off by the $ for some simple pieces of aluminum. A sheet metal shop here sold me some aluminum and cut it into circles for $2.00 total. I fabricated a reflector from those, bonded the pieces with JBweld and mounted it on the uprights of the radar arch. Pictures are on page 3 of the C-Cakes photo album. Not at all hard to do and I feel a little better. It is not certified by any government agency but the geometry is the same as the commercial ones and physics is physics.

[thataway]

Any of the refectors work--some better than others. The foam/foil reflectors seem to work, as do the folding square or aluminum. Even foil over plywood works well. The "Rain catch" position seems to work well.

Having a radar on, may give some interference to a boat with a radar with similar frequency radar, and thus show the boat better. But it does not act as a reflector or intrinsically increase the radar image.

[journey on]

When we had our sailboat in Lake Michigan, another boat asked us to check their radar image both with and without their reflector up. Using a 2 kW Raymarine CRT, I could see no difference.

Has anyone tried to scan a boat with and without their reflector (same boat)?

We also had a radar detector. Worthless, because of too many radar signals. Even in the middle of the ocean, we'd get a signal; I assume from satellites. I think that the best radar signal is from the radar on your boat.

Boris

[marco422]

[quote="colobear"]I wanted a radar reflector but was put off by the $ for some simple pieces of aluminum. A sheet metal shop here sold me some aluminum and cut it into circles for $2.00 total. I fabricated a reflector from those, bonded the pieces with JBweld and mounted it on the uprights of the radar arch. Pictures are on page 3 of the C-Cakes photo album. Not at all hard to do and I feel a little better. It is not certified by any government agency but the geometry is the same as the commercial ones and physics is physics.[/quote]

As far as I know the geometry is fairly critical for this type of reflector. If the angles are a few degrees off 90 degrees, it significantly decreases the reflective profile.

[colobear]

I think you are right about the geometry. When I studied radar back in the dark ages we learned that the radar cross section of a target with some kind of reflector was substantially bigger than the same target without a reflector; so I figure even if my home built reflector is a degree or two off my boat will still be a substantially bigger target than without it. When I decided on that construction I used the same geometry as the folding circular reflectors and a true 90 degree square to set my angles and tried to keep to that accuracy. The commercial ones have a loose enough assembly to be off a degree or two and figure if it is good enough for them it will likely be good enough for me. Anyway, I feel better with it there

[Almas Only]

I suppose reflectors work, and have read the studies comparing one to the other. Lots of nice numbers, graphs, etc., but what always seems to be lacking are photos of radar screens, showing significant, or even noticable, differences in actual returns. Anyone come across a link to this info?

Whenever we're boating with a group, and someone hangs up one of the disk type reflectors, I make a point of looking at the radar returns, while I change position, range, etc. I've never been able to see an improvement with the reflector up. I do detect differences from one boat to the other, which I attribute to different engine blocks, running gear, etc. But, opening up and deploying a disk reflector has yet to show up on my radar screen.

I haven't done any definitive testing, and perhaps at longer range, or in rougher seas, the reflector would make a difference. I also haven't targeted any of the tri-lens reflectors, which I understand do a better job. My radar is a JRC 1500, which is not top of the line, and perhaps a better set would pick up the differences.

Others have reported improved returns. What's going on?

[Alyssa Jean]

My only experience in a group was about 2-3 years ago when about 6-7 C-Dorys headed across Rosario Channel to Lopez. I was in the front and all where in somewhat of a line spread over about 1/2- 1 mile. It was reported by several others that I "painted" a much bigger picture than others. I have the standard three aluminum disks fitted together to form a sphere. I carry it right under the high arch.

If you are traveling in or through Canadian waters they are required. Although I don't know what they do to enforce it. I guess if you have an incident that gets investigated you better have one.

Anything that makes you look bigger on someone else's radar is a good thing. It is just like driving a car. I don't worry so much about me, it's the other guy I worry about. I want to be seen.

[Grumpy]

David, From discussion with the Canadian "coasties" I believe the requirement to meet their standards (on a number of things including radar reflectors) only kick in after 30 days if my memory is correct.
Enforcement is another issue.

Merv

[Alyssa Jean]

Thanks Merv, I think I know that at some earlier point in my life. I can't remember the other things I have forgotten.

[Valkyrie]

Back in my sailing days I used one of the Davis Instruments foam/aluminum foil reflectors mounted high on a flag halyard right under one of the spreaders. On the Chesapeake I hailed a passing Coast Guard vessel and asked for info on my radar return. They replied that I had a radar signature nearly identical to a large, steel commercial fishing vessel nearby. That surprised the heck out of me, but also made me feel a lot more comfortable as a singlehander.

Nick
"Valkyrie"

[Grumpy]

David,

Here's one for you. If you trailer your boat into Canada from USA via Nexus you will not be given a "magic" number to hang in your window next to the dock.

What was the first question?

Merv