NBC 5 in Dallas Debuts Powerful S-Band Radar

[Steve Miller]

NBC 5's brand new S-band radar is among Texas' most advanced weather radar tools. Chief Meteorologist David Finfrock explains what makes it so unique.

A really great video story if you like learning about the innards of S-band radars: http://www.nbcdfw.com/news/local/NBC-5-Debuts-Powerful-S-Band-Radar_Dallas-Fort-Worth-401572245.html

 

[rdale]

Someone explain to me how it's still S-Band but runs at a "higher frequency" that gives it better resolution than NWS S-Band?

 

[Jeff Duda]

S-band refers to a range of frequencies from 2-4 GHz, so technically you could have two weather radars operating in the S-band but at different frequencies. Also, for parabolic dish antennas, the angular beamwidth is directly proportional to the wavelength of radiation and inversely proportional to the effective area of the antenna. So there are two ways to increase angular resolution on a radar system - use a bigger dish for the same frequency (wavelength) or increase the frequency without changing the antenna size. I'm not sure of the proportionality constant, so I'm not sure what the net change is from going from a 13-foot diameter dish antenna at C-band (wavelngth ranging from) 3.75-7.5 cm) to a 20-foot diameter antenna at S-band (wavelength ranging from 7.5-15 cm).

Off topic: imagine people trying to use mobile Doppler radars if these physical rules weren't the way they are.

 

[rdale]

Here's the spec sheet - I guess it depends on what options they went with?

http://www.eecweathertech.com/pdf/EEC-Defender-SBAND-specs-2016.pdf

 

[Jeff Duda]

According to those specs and crossreferencing with the video, they must have gone with the SK1000H model, which seems to have a pretty limited range of available wavelengths (from 8.33-8.57 cm). If you're comparing that to the WSR-88Ds that nominally run at 10 cm wavelength, then they technically are making a true statement.