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Discussion Starter #1
I was just wondering if a car radar detector would alert you to a ship near by that had his radar turned on. I have used one for years while driving and they seem to work great. The best use I have had is while driving in Nebraska, completely flat land with every little town having a radar gun toting cop out hunting. It seems like with all the different bands a unit searches that it would work at sea. Just wondering, another safety tool. Very inexpensive also.
 

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Asleep at the wheel
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If there was only one boat around, maybe (I haven't looked into whether the ship radars use X, K, or Ka bands; if not, then it won't work). But if there was more than one boat, you'd be getting pings all the time. I imagine it would get a bit annoying. Now, if you're in the middle of the ocean and worried about getting run over, then it makes sense (assuming the detector will actually pick up the ship's radar). But if you're in the Chesapeake Bay or Delaware River, for example, it would probably just drive you nuts.
 

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Barquito
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Here is what fellow SailNetter, Jim Sexton, wrote a few years ago:

Another radar warning device is one that detects a radar pulse and sets off an alarm. Unfortunately this type of radar detector does not commercially exist in the marine market. A land based X-band radar detector used to detect police radars is not very expensive and on a vessel at sea would alert you to the presence of another operating radar in time to fire up your radar, search for a return, and determine if there is any danger of a collision. While not very useful in a harbor near land, it should provide some warning at sea. Obviously this type of radar detector would not be of any value to you if the other vessel was operating in the S-band, had its radar in standby mode, or off altogether. The land-based police radar detectors typically operate in the X, K , Ka, and Laser bands but not at all in the S-band. The S-band radar is in the 2 to 4 GHz range (2000 to 4000 MHz) while the X-band is in the 8 to 12 GHz range (8000 to 12000 MHz). To the best of my knowledge, no one makes a radar detector that operates in the S-band.
 

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Closet Powerboater
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What a great idea! Police radars are X band, and so are our small marine units. Ships use both S and X band with S band being for longer ranges and X band for short ranges. You'd have to ask someone who is one one of these ships to know if they use just S band radar at sea or if they use both S and X at the same time at sea.

MedSailor
 

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There are marine units available that have alarms and some sort of display capability.

They were discussed in the book on Black Feathers, the Cal 20 that finished the solo transpac race a few years ago. I remember them being discussed at length and compared to AIS, IIRC, he said that he got pings on the radar detector long before getting them on his AIS display.

I think it's a great idea, but I am curious why it never caught on. I had to really look to find information on the marine units and have yet to see a boat with one installed (aside from Black Feathers).

EDIT:

I believe this was it:

http://www.sea-me.co.uk/about.html

I was wrong, it doesn't have display capability but it does have an alarm that goes off when you get hit with radar.
 

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baDumbumbum
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The two passive detectors/active return marine units are from Sea-Me (as Shinook linked to) and EchoMax. Both use very little power in detect mode; when they return a signal (highly amplified), your vessel appears roughly the size of the QE2 on the screen of whomever pinged you. This is good, much better than passive reflectors which lose signal per the inverse square rule both incoming and outgoing, and which return signal may not show up on a radar set with the gain turned down to reduce false positives.

Both EchoMax and Sea-Me sell single band or dual band units. The reason they have not caught on is a price tag between $800 and $1000 USD. It seems likely cheap & ubiquitous AIS will, in the near future, consign this very nifty product to the dustbin, next to Loran C.;)
 

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Barquito
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So, back the the OP question, it looks like X-band detection might be reasonable if staying near the shore. That is, if what they say in the add for the Sea-Me unit applies to US waters. I would be interested to know if anyone knows what radar bands are used in the US waters (and Great Lakes).
 

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the pointy end is the bow
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I'm glad you asked this question, because it's something I've been thinking about as well. We knew a guy who cruised in the 80's and used a car RADAR detector during off shore passages and he said it worked really well. But that was in the 80's. A person could maybe borrow one and drive down to a shore with commercial traffic and see if it beeps?
 

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I last had a car radar detector back when I was a teenager, a zillion years ago. I have no idea what changes they've undergone since then but if I'm reading this thread correctly, all you want is the ping? You don't want a display to tell you where the object is located, whether you're on a collision course, or anything else a boat's radar screen can tell you?

I don't have radar, I'm just trying to think through the argument for using the car radar instead.
 

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Barquito
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Another thing about car radar detectors is that they would have a limited arc of detection. I think it would be about 120 degrees in the direction it is pointed. These radar detectors work well on the road for detecting signals from the rear (like when a cop is following you), because the radar signal is reflected off stuff ahead of you and detected from the front. In the open ocean there wouldn't be much to reflect the signal from ships that are in the 240 degree arc behind the car radar detector. You would either need to get the more expensive dual antenna detectors, get more than one cheap detector, or build some kind of refractor/diffuser thing that goes in front of the detector.

OK, radar-smart people, step up to the plate! Will any of this work?
 

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Discussion Starter #12
I still use mine and successfully on the road. I see them at the local consignment store for around 5 bucks. I don't want to put radar on my little boat, (costs too much), but if I could change the directional antenna to Omni directional then I think it would let me know if a ship was near. Mine also has a limiter for congested areas and can be set for audio, light signal or both. I think I will play with a unit and see what I can do with the antenna.
 

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Guys the days of the marine radar detector passed us by in the 80's... I still have a few boats out there with them, though none are still operational.. Google CARD or RDF and you may find some info...

Having a radar is far safer than trying to detect it on a boat that does not have it, that you are on a collision course with....;)
 

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Guys the days of the marine radar detector passed us by in the 80's... I still have a few boats out there with them, though none are still operational.. Google CARD or RDF and you may find some info...

Having a radar is far safer than trying to detect it on a boat that does not have it, that you are on a collision course with....;)
I'm probably one of the few boats out there today that has a C.A.R.D. unit. It's the dome-shaped antenna, the one to the right of the 3 receivers on the rail below...



I've had it since long before anyone dreamed of AIS, of course... It actually works reasonably well, but it's really only useful for one thing: namely, an initial alert of a single vessel running radar offshore... Useful for someone like me who does a lot of singlehanding, but that's about it...

Better than nothing, but of course today almost totally superseded by AIS. And, it has a number of limitations:

It only gives a very approximate indication of the target bearing, and no real way to determine range...

Once multiple targets start showing up, it becomes almost all but worthless. In coastal waters, all it will often indicate is "You are surrounded by a bunch of boats running radar"... :)

Once a target shows up, there is no way to Cancel that particular alert. You can turn the volume down, but then have to monitor the screen...

But, here's the biggest downside: You can't use it while running radar yourself, as your own radar pretty much overwhelms any other signals. So, it's only real value, is the initial contact with another vessel offshore if you don't have radar yourself, or are not running it continuously...

I still use mine, and consider it to be sort of a belt and suspenders supplement to AIS, and it's certainly better than nothing... However, it was fairly expensive back in the day, and I probably wouldn't buy one new again today... Anyone who comes across one on EBay for 100 or 200 bucks, however, it might be worth it... Again, very much depends on the sort of sailing you do, wouldn't do much for you sailing coastal Maine, I don't think... :)
 

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Barquito
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Having a radar is far safer than trying to detect it on a boat that does not have it, that you are on a collision course with....
I agree. However, in my case, and maybe the OP, I am not in a position where I want to buy a radar system. Probably AIS would make more sense. I just like the idea of MacGyver-ing together some $5 radar detectors. In addition, when I get above hull speed, I don't want smokey pulling me over and giving me a ticket.
 
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