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#11
posted to rec.boats.cruising
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X-band and S-band Radar
On Wed, 07 Jan 2009 06:48:33 -0600, Geoff Schultz
wrote: So am I correct in stating that the S-band radar is typically used for long distance and X-band for shorter distance? Is it also valid to assume that if a ship has S-band that it will also have X-band? Basically correct. The National Weather Service uses S Band radar for weather tracking out to 200 miles or so using high power and large antennas. I'm not sure that it is safe to assume that large ships will always be using an X Band radar if that is what you are driving at. |
#12
posted to rec.boats.cruising
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X-band and S-band Radar
Wayne.B wrote in
news On Wed, 07 Jan 2009 06:48:33 -0600, Geoff Schultz wrote: So am I correct in stating that the S-band radar is typically used for long distance and X-band for shorter distance? Is it also valid to assume that if a ship has S-band that it will also have X-band? Basically correct. The National Weather Service uses S Band radar for weather tracking out to 200 miles or so using high power and large antennas. I'm not sure that it is safe to assume that large ships will always be using an X Band radar if that is what you are driving at. What are the radar requirements for ships up to 300 tons and over 300 tons? -- Geoff www.GeoffSchultz.org |
#13
posted to rec.boats.cruising
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X-band and S-band Radar
On Wed, 07 Jan 2009 08:46:13 -0600, Geoff Schultz
wrote: I'm not sure that it is safe to assume that large ships will always be using an X Band radar if that is what you are driving at. What are the radar requirements for ships up to 300 tons and over 300 tons? Don't know the answer to that but for US registered ships the answer can be found in CFR 46: http://law.justia.com/us/cfr/title46/46cfrv1_02.html Vessels registered elsewhere typically fall under the SOLAS regulations: http://tinyurl.com/ax2t6y |
#14
posted to rec.boats.cruising
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X-band and S-band Radar
Ships are required to have at least two radars. Usually, one will be 3cm and the other 10 cm....... usually....... Wayne.B wrote in : On Wed, 07 Jan 2009 08:46:13 -0600, Geoff Schultz wrote: I'm not sure that it is safe to assume that large ships will always be using an X Band radar if that is what you are driving at. What are the radar requirements for ships up to 300 tons and over 300 tons? Don't know the answer to that but for US registered ships the answer can be found in CFR 46: http://law.justia.com/us/cfr/title46/46cfrv1_02.html Vessels registered elsewhere typically fall under the SOLAS regulations: http://tinyurl.com/ax2t6y |
#15
posted to rec.boats.cruising
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X-band and S-band Radar
In article ,
Geoff Schultz wrote: Bruce in alaska wrote in : In article , Wayne.B wrote: The key difference is that they operate in two completely different frequency ranges, much like the difference between VHF and UHF television. X-band is from is from 7 to 12.5 GHz, S-band is at a lower frequency (longer wavelength) between 2 and 4 GHz. Because of the shorter wavelength, X band radar can resolve between smaller objects but usually has less range because of increased signal attenuation. S band typically has greater range but requires much larger antennas, too large for the average small to mid size pleasure boat. Add to the above, that Marine S-Band Radars are 2.9 - 3.2 Ghz and Marine X-Band Radar are 9.3 - 9.5 Ghz. S-Band Radars are much more likely to be blinded by Snow and Heavy Rain that X-Band Radars. S-Band Radars require Antennas that are MUCH Larger than X-Band Radars due to the Frequencies involved. S-Band Radars predate X-Band Radars in production because Magnetrons were easier to build, for the Lower Frequencies. Most Marine WWII Radars were S-Band, including the venerable SO Radar fitted to the PT Boats, who's antenna looks like an upside down R2D2 on a Mast. So am I correct in stating that the S-band radar is typically used for long distance and X-band for shorter distance? Is it also valid to assume that if a ship has S-band that it will also have X-band? -- Geoff www.GeoffSchultz.org Range is relative in the Radar Biz. Radar Horizon is determined by LOS, AND Horizon Lensing and Refracting Issues, but normally these are minor. S-Band does get a bit more Refraction than X-Band but the difference is minor. S Band usually has Higher TX Power. Just about ANY Vessel that has a S-Band Radar fitted, will also have an X-Band Radar fitted as well. The really BIG difference between the two, are Target Resolution, and Water Vapor Reflectiveness. -- Bruce in alaska add path after fast to reply |
#16
posted to rec.boats.cruising
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X-band and S-band Radar
On Jan 7, 8:46*am, Geoff Schultz wrote:
Wayne.B wrote innews On Wed, 07 Jan 2009 06:48:33 -0600, Geoff Schultz wrote: So am I correct in stating that the S-band radar is typically used for long distance and X-band for shorter distance? *Is it also valid to assume that if a ship has S-band that it will also have X-band? Basically correct. *The National Weather Service uses S Band radar for weather tracking out to 200 miles or so using high power and large antennas. I'm not sure that it is safe to assume that large ships will always be using an X Band radar if that is what you are driving at. What are the radar requirements for ships up to 300 tons and over 300 tons? -- Geoffwww.GeoffSchultz.org CFR Subpart 32.15—Navigation Equipment 32.15–30 Radar—T/OC. Pretty basic requirements Geoff. 1,600 ton+ must have a radar, no specific type or back-up required. Joe |
#17
posted to rec.boats.cruising
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X-band and S-band Radar
In article ,
Geoff Schultz wrote: Wayne.B wrote in news On Wed, 07 Jan 2009 06:48:33 -0600, Geoff Schultz wrote: So am I correct in stating that the S-band radar is typically used for long distance and X-band for shorter distance? Is it also valid to assume that if a ship has S-band that it will also have X-band? Basically correct. The National Weather Service uses S Band radar for weather tracking out to 200 miles or so using high power and large antennas. I'm not sure that it is safe to assume that large ships will always be using an X Band radar if that is what you are driving at. What are the radar requirements for ships up to 300 tons and over 300 tons? -- Geoff www.GeoffSchultz.org SOLAS says that a Operational Radar MUST be fitted and operational for any SOLAS Required Vessel to leave Port. Also the Required Radar MUST have ARRPA. Most SOLAS Required Vessels will have TWO compliant RADARs fitted so that they can still leave Port with one Down, should Repairs not be available in the last Port of Call. ALL US Flagged Vessels over 300GT are Classed as SOLAS Required Vessels, via Title 111, Part 11, of the Communications Act of 1934, as amended. Vessels under 300GT have different requirements, detrmined by Class and Operations, HOWEVER, if the fall under the USCG Fishing Vessel Safety Act as amended, they are required to have a working Radar when leaving Port. Most commercial Vessels will have two Radars fitted, just to have a backup, and ARRPA is NOT Required. -- Bruce in alaska add path after fast to reply |
#18
posted to rec.boats.cruising
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X-band and S-band Radar
In article ,
"Steve Lusardi" wrote: Bruce, Perhaps I am confused, but I have been taught that the larger wavelength radar (S-Band) is not affected by weather as much as X-Band. It will penetrate weather and resolve targets behind the weather better than X-Band. Where X-Band radars are better at displaying the weather itself. I have also been told that S-Band discriminates ice from sea clutter better than X-Band. Steve Maybe your weather is different than the stuff we get up here in the North Pacific, BUT S-Band is useless in our Snow Storms, and our X-Band are reduced significantly. S-Band has been used for YEARS to monitor Water Vapor and Cloud Density, by the NOAA/USWB, and a lot of the original Research was done in Seattle, by a couple of Radar Techs from the old Radar Electric Shop. I worked on a few of the later units with the Researcher, just as the FCC STA's were expiring, to get them renewed. -- Bruce in alaska add path after fast to reply |
#19
posted to rec.boats.cruising
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X-band and S-band Radar
On Wed, 07 Jan 2009 08:46:13 -0600, Geoff Schultz
wrote: Wayne.B wrote in news On Wed, 07 Jan 2009 06:48:33 -0600, Geoff Schultz wrote: So am I correct in stating that the S-band radar is typically used for long distance and X-band for shorter distance? Is it also valid to assume that if a ship has S-band that it will also have X-band? Basically correct. The National Weather Service uses S Band radar for weather tracking out to 200 miles or so using high power and large antennas. I'm not sure that it is safe to assume that large ships will always be using an X Band radar if that is what you are driving at. What are the radar requirements for ships up to 300 tons and over 300 tons? -- Geoff www.GeoffSchultz.org http://www.ybw.com/pbo/pdfs/radar_reflectors.pdf See section 1.1, in particular. (SOLAS) |
#20
posted to rec.boats.cruising
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X-band and S-band Radar
On Jan 6, 7:23*pm, Geoff Schultz wrote:
In an attempt to discuss something related to cruising, can someone explain the differences between X-band and S-band radar systems? *From what I know, S-band is used on large ships and X-band is used on vessels less than 300 tons. -- Geoffwww.GeoffSchultz.org Geoff - X band is mandatory on all solas vessels - for the purpose of search and rescue. Sarts been now mandatory. Most commercial vessels will have two radars one x and one s but in many cases, older vessels will have two x band radars. One radar must have a arpa facility if the vessel is over 1600tons. In my part of the world Southern Africa - X band is pretty useless in tropical storms with the S band giving better target discrimination.(10cm wavelength against 3cm wavelength) S band radars also generally have 12ft antennas against the 4/6 or 9 foot x band scanners. Rgds Mike |
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