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Geoff Schultz Geoff Schultz is offline
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First recorded activity by BoatBanter: Oct 2006
Posts: 454
Default X-band and S-band Radar

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