Radio Spectrum Bands
The use of letters to designate bands has long ago been declared obsolete.
Nevertheless, people seem to continue to use them and add more letters as
users move up the microwave spectrum. The original definitions had very
specific non-overlapping definitions (not counting sub-band definitions).
Modern usage seems to associate the bands with waveguide ranges. As best as
I can figure out, here is the modern usage.
P 225-390 MHz
L 0.39-1.55 GHz
S 1.55-3.9 GHz
C 3.9-6.2 GHz
X 6.2-10.9 GHz
Ku 10.9-18 GHz (originally 12.4-18 GHz)
K 18-26.5 GHz (originally 10.9-36 GHz)
Ka 26.5-40 GHz (originally 33-36 GHz)
Q 33-50 GHz (originally 36-46 GHz)
U 40-60 GHz (originally 46-56 GHz)
V 50-75 GHz
E 60-90 GHz
W 75-110 GHz
F 90-140 GHz
D 110-170 GHz
G 140-220 GHz
Y 170-260 GHz
J 220-300 GHz