Active Radar reflectors

[johnq]

I am looking to be able to give a better signal at sea (Blue water) to other vessels using radar . I have a Furdell blipper and have a steel boat, however in practice a yacht radar will pick you up to a distance of about 3 miles - large ships possibly a bit further

Does anyone have any experiance and/or know of any reviews about Active Radar reflectors

e.g. See-Me - see attached link.

Http://www.speedseal.com/seame/welcome.htm

Thanks

John Q


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[ccscott49]

With a blipper and a steel boat, I think you should be fine. The problem is normally not that you don't appear on their radar, the problems' they aren't looking at the radar or anything else! Especially deep sea. IMHO

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[johnq]

Quite agree with your comment that someone has to be looking at the RADAR to see you, however, I understand a lot of merchant ships rely on the Radar Guard Zone function to alert them if anyone is about.

I know from personal experiance that trying to raise ships at sea on VHF to get them to confirm that they have seen you is a bit hit and miss. What I am after is to make a big target so that it is picked up and ring loud bells.

John Q

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[ccscott49]

Good luck.

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[AndyL]

Wouldn\'t bank on steel helping too much.

Or a reflector come to that. Sailed to Singapore last November in a 70' steel ketch. We spoke to 2 container ships that passed by - neither of them could see us on their radars, even when they had visual on us. I suppose the watch officers had set their radars to pick up only things as big as ships to avoid "false" alarms. The active thing sounds a good idea to me.

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[snowleopard]

Re: Wouldn\'t bank on steel helping too much.

bit of a black art, this radar reflection business. i have a carbon mast and the manufacturer told me it was a good reflector. when i called up a passing ship he said he'd seen me form 8 miles.

the 'active' radar reflector is called a transponder. you can buy one for emergency use only which puts up a row of 10 dots on the ship's radar screen. it's called SART (search and rescue transponder). don't know of any similar device for routine use that's within yachties' pockets.

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[ccscott49]

Re: Wouldn\'t bank on steel helping too much.

There is an active antenna for yachts, cheap enough I suppose, but I just wont bother. I still think the ship has to be looking and as recent events (Channel) have proven they aren't, this is from experience of being on big ships, deepsea.

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[HaraldS]

Re: SART and Active reflector are..

two different things. As you say the SART is like a transponder that sets off a series of bursts when hit by a radar signals, creating a dotted line on the receiver screen.
The active 'reflector' sends just one short signal immediately upon arrival of an incoming pulse. The time latency is less then 3 meters, so the position accuracy of the faked reflection is very high. What's send off however is a lot stronger than what is reflected of the original beam by your boat. At least that is the case at a certain distance. As you get closer, say 2 to 3 miles, the actual reflection will be as strong the the fake signal. Radars assume that with growing distance, (time to wait fro an echo), the signals will get weaker and weaker, and regulate their amplifier accordingly. The net effect of the active response is that you will show up bigger than life, when you are further away, and more normal when getting closer. The biggest effect is between 8-12 miles. I think that's exactly what you want, the earlier and longer you show up on another radar screen, the higher the likelyhood somebody will spot it. Also if somebody thinks his hull is strong enough to ignore weak signals ;-), he might be lead to believe that you could be a danger to him.

Based on that philosphy, I do have an active reflector (and a blipper). Mine is called Ocean Centry and was the first on the market, but now there are a few of those and prices have dropped somewhat.

One more thing. Since the active reflector has a receiver, it can alarm you on signal reception, (as long as you don't run your own radar). I have seen enough ships passing by with none of their radars rotating, that I keep my radar on at night...

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