Sparrow II active radar homing missile

[Heatloss]

Think they'd be able to make an 8" diameter X-band seeker that early?

A K-band seeker would be more or less worthless.

The Canadian document for it explicitly states attenuation of 1/10 db/mile to water in the atmosphere. K used to encompass Ku and Ka, and given that attenuation of 1/10 db/mile, I suspect it's a low Ku band seeker, so not far off from the upper bounds of X, which would suffer less against clouds and rain unlike the other frequencies in the K band.

Attenuation would be high in clouds, but that's something experienced by X band radars too. I wouldn't call it worthless.

 

[overscan (PaulMM)]

The Canadian document for it explicitly states attenuation of 1/10 db/mile to water in the atmosphere. K used to encompass Ku and Ka, and given that attenuation of 1/10 db/mile, I suspect it's a low Ku band seeker, so not far off from the upper bounds of X, which would suffer less against clouds and rain unlike the other frequencies in the K band.

Attenuation would be high in clouds, but that's something experienced by X band radars too. I wouldn't call it worthless.

Yep, the K band used for 1959s seekers is the low centrimetric range near X band not milimetric. It eases seeker design at small diameters a bit.

 

[overscan (PaulMM)]

You mean in general?

Before doppler beam sharpening Ku band radars were preferable for air to surface / ground mapping as the smaller wavelength was able to give higher resolution mapping, in addition to allowing smaller antennas with good gain (which was more relevant to missiles).

With the advent of multirole aircraft, the drawbacks to Ku band meant a general switch to X band with software techniques to improve resolution of mapping.

 

[Heatloss]

in addition to allowing smaller antennas with good gain (which was more relevant to missiles).

This was the answer. I realize you already answered it, so I deleted my comment. Sorry, I'm tired and I didn't read closely enough.
I get the other advantages to Ku/Ka over X, I just wasn't aware of that one and it didn't register when I read that.