What's EW - Electronic Warfare?

EW in short

You look for any radar emmision, then get the bearing and indentify the radar if possible. If there are more than one radar in the same bearing you can even identify the (war-) ship class. You can take fingerprints of it's radars. So it's possible for you to identify not only the ship class but even the single ship if you meet it again.
Identification of ships is neccessary because your own radar operators get only the blip on their radar but don't know who it is. More important during maneuvers warships turn off their radars (called silence) most of the time while the EW operators are looking for other ships. If the EW-op gets a radar emmision from the target your own ship can turn on their target tracking radars and immediately fire their missiles!
One important thing to note: the range of EW is larger than the range of the radar you intercept! This is because after a certain distance from the emmiting ship the radar waves are to weak to return all the way to their "home ship" if they hit something. But they still travel on and can be intercept by the EW antenna of another ship out of the radar range!

Division of EW


Designation             Freq Range (MHz)

HF                      3-30
VHF                     30-300
UHF                     300-1000
L                       1000-2000
S                       2000-4000
C                       4000-8000
X                       8000-12000
Ku                      12000-18000
K                       18000-27000
Ka                      27000-40000
V                       40000-75000
W                       75000-110000
mm                      110000-300000

Radar Handbook, Second Edition
Merrill I. Skolnik, 1990
Page 1.14
-most common bands are S and X (most), if you're looking for a radar in this bands it can become really difficult in crowded areas (eg English Channel, German Coast)