Talk:E band

Two bands

Can you explain the reson for having two E-bands one by Nato and one by Waveguide ?

Well, NATO chose to define bands for electronic counter measures (ECM) applications, because the older radar bands (IEEE bands) were not well suited to describe some non-NATO (Soviet) systems. According to this book anyways. NATO named these bands systematically in alphabetical order, starting with the letter A for the lowest frequency range (0 to 250 MHz), and roughly doubling the frequency with each letter, reaching up to the letter M; the letter E happens to be in that range.
The letters used for waveguide frequency bands don't follow such a nice scheme. Because the recommended maximum frequency for a rectangular wave guide is roughly 1.5 times the recommended minimum frequency, more waveguide sizes are needed to cover the spectrum than there are IEEE band and than there are NATO bands, and accordingly more waveguide sizes have been standardized. Overviews of rectangular waveguide sizes are available e.g. here and here. If you look at the latter list, above the X-band (WG16) frequencies, there waveguides with recommended frequency ranges that correspond to IEEE/radar bands (WG18, WG20, WG22, etc.) Then there are the waveguides WG17, WG19, WG21, which have their center frequency at the edges of the radar bands. Because neither the NATO nor the IEEE band schemes are well-suited to describe these waveguides, the bands associated with these waveguides are sometimes referred to as "waveguide bands".
This doesn't explain why the letter E was chosen for the to 60 to 90 GHz range, but I hope it motivates why the letter E is used to refer to two completely separate bands. Conquerist (talk) 17:35, 31 July 2014 (UTC)