X-band and S-band Radar
Geoff Schultz
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.
-- Geoff
www.GeoffSchultz.org
Goofball_star_dot_etal
<geoff"at"@geoffschultz.org> 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.
>
The dimensions of an antenna array of given geometry/gain/beamwidth
etc. are scaled according to wavelength. Big wavelength, big anttenna,
big boat. Next..
Wayne.B
<geoff"at"@geoffschultz.org> 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.
Geoff Schultz
news:ff57m49kbvi58lmog...@4ax.com:
Wayne,
Thanks for actually answering the question instead of providing a smart-ass
answer that didn't provide any useful information.
-- Geoff
www.GeoffSchultz.org
Goofball_star_dot_etal
<geoff"at"@geoffschultz.org> wrote:
If you can judge the accuracy of the answer then you have no need to
ask the question. Angular resolution is determined by the horizontal
beamwidth and range resolution by (effective) pulse width, not
wavelength. as such.
Bruce in alaska
Wayne.B <waynebatr...@hotmail.com> wrote:
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.
--
Bruce in alaska
add <path> after <fast> to reply
KLC Lewis
"Geoff Schultz" <geoff"at"@geoffschultz.org> wrote in message
news:Xns9B8B8CF879D...@216.196.97.131...
Please allow me to correct this shortcoming:
The difference is that one is spelled with an "X"...
Steve Lusardi
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
"Bruce in alaska" <fa...@btpost.net> wrote in message
news:fast-C12534.1...@netnews.worldnet.att.net...
Goofball_star_dot_etal
wrote:
> S-Band Radars are much more likely to be
>blinded by Snow and Heavy Rain that X-Band Radars.
..or vica versa..
http://www.cosis.net/abstracts/ERAD02/00131/ERAD02-A-00131-1.pdf
Geoff Schultz
news:fast-C12534.1...@netnews.worldnet.att.net:
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
Wayne.B
<geoff"at"@geoffschultz.org> 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.
Geoff Schultz
news:o5e9m41aokh4igmg2...@4ax.com:
What are the radar requirements for ships up to 300 tons and over 300 tons?
-- Geoff
www.GeoffSchultz.org
Wayne.B
<geoff"at"@geoffschultz.org> 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:
otnmbrd
Ships are required to have at least two radars. Usually, one will be 3cm
and the other 10 cm....... usually.......
Wayne.B <waynebatr...@hotmail.com> wrote in
news:a6l9m4ldj8af2430s...@4ax.com:
Bruce in alaska
Geoff Schultz <geoff"at"@geoffschultz.org> wrote:
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.
Joe
> Wayne.B <waynebatrecdotbo...@hotmail.com> wrote innews:o5e9m41aokh4igmg2...@4ax.com:
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
Bruce in alaska
Geoff Schultz <geoff"at"@geoffschultz.org> wrote:
> Wayne.B <waynebatr...@hotmail.com> wrote in
> news:o5e9m41aokh4igmg2...@4ax.com:
>
> > On Wed, 07 Jan 2009 06:48:33 -0600, Geoff Schultz
> > <geoff"at"@geoffschultz.org> 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
"Steve Lusardi" <steve...@lusardi.de> 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.
Goofball_star_dot_etal
<geoff"at"@geoffschultz.org> wrote:
>Wayne.B <waynebatr...@hotmail.com> wrote in
>news:o5e9m41aokh4igmg2...@4ax.com:
>
>> On Wed, 07 Jan 2009 06:48:33 -0600, Geoff Schultz
>> <geoff"at"@geoffschultz.org> 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)
coxtr...@gmail.com
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