radar reflectors - SailNet Community

   Search Sailnet:

 forums  store  


Quick Menu
Forums           
Articles          
Galleries        
Boat Reviews  
Classifieds     
Search SailNet 
Boat Search (new)

Shop the
SailNet Store
Anchor Locker
Boatbuilding & Repair
Charts
Clothing
Electrical
Electronics
Engine
Hatches and Portlights
Interior And Galley
Maintenance
Marine Electronics
Navigation
Other Items
Plumbing and Pumps
Rigging
Safety
Sailing Hardware
Trailer & Watersports
Clearance Items

Advertise Here






Go Back   SailNet Community > General Interest > General Discussion (sailing related)
 Not a Member? 


Reply
 
LinkBack Thread Tools
  #1  
Old 06-07-2007
sailortjk1's Avatar
Senior Member
 
Join Date: Dec 2005
Location: Porter, IN
Posts: 4,647
Thanks: 1
Thanked 1 Time in 1 Post
Rep Power: 10
sailortjk1 has a spectacular aura about sailortjk1 has a spectacular aura about
radar reflectors

Found this from another link supplied in a different thread.
I thought it very interesting.
Lots to read through.
I was surprised by the findings.
I always thought that the tube type reflectors were the choice of most sailors. These findings result in a different recommendation.

Of course the best protection will cost you a lot more $$$$


http://www.setsail.com/c_central/tec...Reflectors.pdf


SetSail.com - the serious cruising sailor's website
__________________
Courtney is My Hero

If a man is to be obsessed by something, I suppose a boat is as good as anything, perhaps a bit better than most - E.B. White
Reply With Quote Share with Facebook
  #2  
Old 06-07-2007
Idiens's Avatar
Larus Marinus
 
Join Date: Jan 2007
Location: Brussels
Posts: 1,756
Thanks: 0
Thanked 0 Times in 0 Posts
Rep Power: 8
Idiens is on a distinguished road
Frightening isn't it. However, I wonder how two or three tubular reflectors might fare, one on each shroud and one on the backstay.
Reply With Quote Share with Facebook
  #3  
Old 06-07-2007
sailingdog's Avatar
Telstar 28
 
Join Date: Mar 2006
Location: New England
Posts: 43,291
Thanks: 0
Thanked 10 Times in 10 Posts
Rep Power: 13
sailingdog is just really nice sailingdog is just really nice sailingdog is just really nice sailingdog is just really nice sailingdog is just really nice
Having multiple radar reflectors can actually work against you from what I've read. Having one good one is probably the way to go.
__________________
Sailingdog

To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.

Telstar 28
New England

You know what the first rule of sailing is? ...Love. You can learn all the math in the 'verse, but you take
a boat to the sea you don't love, she'll shake you off just as sure as the turning of the worlds. Love keeps
her going when she oughta fall down, tells you she's hurting 'fore she keens. Makes her a home.

—Cpt. Mal Reynolds, Serenity (edited)

If you're new to the Sailnet Forums... please read this
To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
.

Still—DON'T READ THAT POST AGAIN.
Reply With Quote Share with Facebook
  #4  
Old 06-07-2007
Owner, Green Bay Packers
 
Join Date: Sep 2006
Location: SW Michigan
Posts: 10,318
Thanks: 0
Thanked 0 Times in 0 Posts
Rep Power: 12
sailaway21 is just really nice sailaway21 is just really nice sailaway21 is just really nice sailaway21 is just really nice
I might beg to differ with the dog on that one, although i have no evidence to back it up. I would say, from the test results, it does appear that you would have three poorly performing reflectors.

The problem with small boats is that they easily disappear amidst the seas and rain squalls. Although, even ships will disappear in rain squalls. Unless you are steel or aluminum hulled, you are only going to "paint" a ship's radar screen sporadically. Anything you can do to enhance your radar return is advantageous. Multiple reflectors might do that, although additional inefficient ones may not be worth it. Certainly, if you were on a ketch, and could afix multiple high quality reflectors to each mast, I believe you'd increase the frequency of "painting" ship's radar. Regardless of type of reflector, excluding active units, a great many of your echos are going to be reflected either skyward or down into the sea. The boat and reflector are rarely aligned with the incoming radar beam sufficiently to give a good and consistent return. That is one of the reasons that radar watches must be actively held by a crew member, not relying on the "computer".

For multiple reflectors to work against each other they'd have to mounted in close proximity, thereby inducing some type of cancelling effect. As any motorist, dedicated to high speed travel, can tell you, this is very difficult to achieve.(g) Although, mounting them close to one another might induce false echos, that is to say, inaccurate ranging on board the radar equipped vessel.
__________________
“Scientists are people who build the Brooklyn Bridge and then buy it.”
Wm. F. Buckley, Jr.
Reply With Quote Share with Facebook
  #5  
Old 06-07-2007
eherlihy's Avatar
Learning the HARD way...
 
Join Date: Jan 2007
Location: Boston Area
Posts: 3,513
Thanks: 108
Thanked 59 Times in 58 Posts
Rep Power: 8
eherlihy will become famous soon enough
There is a great (and frightening) article in Panbo on this. Look here: Panbo: The Marine Electronics Weblog: Radar reflectors, do they really work?
Reply With Quote Share with Facebook
  #6  
Old 06-08-2007
Idiens's Avatar
Larus Marinus
 
Join Date: Jan 2007
Location: Brussels
Posts: 1,756
Thanks: 0
Thanked 0 Times in 0 Posts
Rep Power: 8
Idiens is on a distinguished road
Quote:
Originally Posted by sailingdog
Having multiple radar reflectors can actually work against you from what I've read. Having one good one is probably the way to go.
Complex subject. The individual returns could cancel, if of nearly equal strength. But the test results for a single reflector show that the observed elevation angle plays a significant role, so having several reflectors at different elevation angles is likely to mean that the strongest return will dominate.
Also in that QineteQ report, did you see the range fades on the 4m target, 30m radar? Those will move about with changed assumptions, but they show the weakness of this type of radar. Even a 10m2 reflector will vanish from the screen at certain ranges. Hence having multiple reflectors at different heights might compensate a little.
On the SeeMe transponder, they didn't test how it responds when the yacht's own radar is on. I suspect that the SeeMe will continuously respond to the yacht's radar and consequently be rejected by the ship's radar, just as it rejects the yacht's radar signal as not being one of its own returns.
Reply With Quote Share with Facebook
  #7  
Old 06-08-2007
Member
 
Join Date: Feb 2007
Location: ny
Posts: 81
Thanks: 2
Thanked 1 Time in 1 Post
Rep Power: 8
ronbo1 is on a distinguished road
Ocean Navigator Online
Ocean Navigator Online - Radar reflector performance

An article in Ocean Navigator, March 2006, by Gallman on passive radar reflectors (he also has a book on the subject) rates reflectors. Bottom line: Tri-Lens (large size) is best while the Davis octahedral is OK and much less expensive.

The boat's angle of heel and pitch is the biggest factor in performance and while most people mount the Davis in the recommended "rain catch" position it's suggested the Davis in the "rain catch" down position will reflect best for boats with low heeling tendencies.

So the question is, why not an Davis EchoMaster on each spreader in both orientations?
Reply With Quote Share with Facebook
  #8  
Old 06-08-2007
TrueBlue's Avatar
Señor Member
 
Join Date: Oct 2004
Location: Narragansett Bay
Posts: 4,853
Thanks: 0
Thanked 1 Time in 1 Post
Rep Power: 12
TrueBlue is a jewel in the rough TrueBlue is a jewel in the rough TrueBlue is a jewel in the rough
Most sailboat owners choose to install those "tubular" reflectors since they're relatively unobtrusive. I've read articles that report, in spite of the lower costs, the Davis Echomaster actually outperformed them. I have yet to be fully convinced that I should switch - although ronbo raises an interesting possibly.
__________________
True Blue . . .
sold the Nauticat
Reply With Quote Share with Facebook
  #9  
Old 06-08-2007
Sequitur's Avatar
... a logical conclusion
 
Join Date: Feb 2007
Location: At Sea
Posts: 430
Thanks: 6
Thanked 0 Times in 0 Posts
Rep Power: 8
Sequitur is on a distinguished road
I've had the large Rozendal Tri-Lens reflector on my last two boats, and I am told I paint like a large ship on my friends' radars. I wouldn't feel safe boating in this area without it. Sequitur's is 10 metres up the mast, just above the radar.
__________________
Cheers,
Michael

To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.

1908 Wildschut Skûtsje

To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.


To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
Reply With Quote Share with Facebook
  #10  
Old 06-08-2007
tenuki's Avatar
Helms ALee!
 
Join Date: Feb 2007
Location: Pacific Northwest, USA
Posts: 1,245
Thanks: 0
Thanked 0 Times in 0 Posts
Rep Power: 8
tenuki will become famous soon enough
1995 Radar Reflector Test
Reply With Quote Share with Facebook
Reply


Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools

 
Posting Rules
You may post new threads
You may post replies
You may post attachments
You may edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is On


Similar Threads
Thread Thread Starter Forum Replies Last Post
Navigating with Radar Jim Sexton Seamanship Articles 0 03-29-2002 07:00 PM
Radar Basics Jim Sexton Seamanship Articles 0 11-14-1999 07:00 PM
Radar Basics Jim Sexton Gear and Maintenance Articles 0 11-14-1999 07:00 PM
Radar Basics Jim Sexton Cruising Articles 0 11-14-1999 07:00 PM
Radar Basics Jim Sexton Her Sailnet Articles 0 11-14-1999 07:00 PM


All times are GMT -4. The time now is 02:03 PM.

Add to My Yahoo!         
Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2014, vBulletin Solutions, Inc.
SEO by vBSEO 3.6.1
(c) Marine.com LLC 2000-2012

The SailNet.com store is owned and operated by a company independent of the SailNet.com forum. You are now leaving the SailNet forum. Click OK to continue or Cancel to return to the SailNet forum.