> > Such a device exists. Pains Wessex makes an "active" radar reflector > that transmits a pulse of radar energy whenever it senses another ship's > radar. It makes your boat appear to have a radar cross section of 80 > square meters(!), which should be adequate to create the desired level > of "respect". It is reasonably small (a cylinder 20" x 2.25") and it > weighs less than four pounds. The primary drawback is that it costs over > $1000. The general term for these things is "transponder." Most light aircraft have them for the same reason being discussed here, with some additional data reply features (and even higher price tags, last I heard). I have a cousin who is a radar electronics engineer for a major defense contracter, to whom I posed just this issue about 4 weeks ago. His opinion was that a broad band transponder for kayaks was totally impractical due to the multiple frequencies used by the different radars of boats and ships of various sizes, vintages and nationalities. "That's like a military ECM problem," or words to that effect, was his reply. I wonder if the model Dan referred to might be designed to work with shore based traffic control radars. This would be highly analogous to the aviation usage. Too bad. I wonder what a tanker and escort tugs would do if they suddenly picked up an echo which appeared to be an invisible Hyundai container ship drifting across their course 8-> Mike Wagenbach *************************************************************************** PaddleWise Paddling Mailing List Submissions: paddlewise_at_lists.intelenet.net Subscriptions: paddlewise-request_at_lists.intelenet.net Website: http://www.gasp-seakayak.net/paddlewise/ ***************************************************************************
"M. Wagenbach" wrote: (regarding active radar reflectors) > The general term for these things is "transponder." Most light aircraft > have them for the same reason being discussed here, with some additional > data reply features (and even higher price tags, last I heard). > > I have a cousin who is a radar electronics engineer for a major defense > contracter, to whom I posed just this issue about 4 weeks ago. His > opinion was that a broad band transponder for kayaks was totally > impractical due to the multiple frequencies used by the different radars > of boats and ships of various sizes, vintages and nationalities. ... I > wonder if the model Dan referred to might > be designed to work with shore based traffic control radars. This would > be highly analogous to the aviation usage. ...<snip>... This is interesting speculation, but based on the manufacturer's claims it would seem to be incorrect. Pains Wessex markets the device as something that is useful in the context of ship radar, not shore-based radar. The device works with all marine X-band radar frequencies (9.2 to 9.5GHz). Of course not all ships' radars are X-band (some are S-band, and there may be others--I don't know much about radar), but it seems as though this would cover a significant percentage of ships in U.S. waters. For example, a quick look at the specifications for Raytheon ship radars (a popular brand in our area) shows that all of the current models are X-band radars. So while this may not be a perfect solution, it seems as though it would improve visibility in a significant percentage of cases. Now if it were only cheaper... Dan Hagen *************************************************************************** PaddleWise Paddling Mailing List Submissions: paddlewise_at_lists.intelenet.net Subscriptions: paddlewise-request_at_lists.intelenet.net Website: http://www.gasp-seakayak.net/paddlewise/ ***************************************************************************
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