What is the difference between Ka and Ku?

[miguelaqui]

I just saw, on an online auction, a D* antenna with a Ku looking LNB. Is that the Ka LNB I've heard that D* will be using? The seller said that it was for int. channels. Maybe that was just something he/she pieced together.

Has D* come out with the Ka dish? What is the differnce between Ku and Ka? Is one more reliable than the other?

 

[Newshawk]

Ku is the "kurz under" band of microwave radiation. It ranges from 12 to 18 GHz and is designated for satellite broadcasting. Ka is the "kurz above" band, ranging from 18-40 GHz. It is also used for satellite broadcasting.

 

[k2ue]

Ku is the "kurz under" band of microwave radiation. It ranges from 12 to 18 GHz and is designated for satellite broadcasting. Ka is the "kurz above" band, ranging from 18-40 GHz. It is also used for satellite broadcasting.

Where did that bizare "kurz" stuff come from? The lettered microwave band designations were first applied in WWII and were PURPOSELY arbirary and confusing, to keep the other side from knowing what frequency ranges were being used. That is well documented.

 

[Newshawk]

Where did that bizare "kurz" stuff come from? The lettered microwave band designations were first applied in WWII and were PURPOSELY arbirary and confusing, to keep the other side from knowing what frequency ranges were being used. That is well documented.

I should hve mentioned that I got the info from Wikkipidia... not a quote but a paraphrase. I was just a bit hurried writing that poast. Sorry.

 

[dragontat002]

KA band for INT? hmmmmm i know there has been talk that DTV may move to KA sometime in order to eliminate tree growth issues, and well LOS issues in general....but i believe that LNB your referring to is the Linear polarization LNB they are using for the international packages

 

[k2ue]

KA band for INT? hmmmmm i know there has been talk that DTV may move to KA sometime in order to eliminate tree growth issues, and well LOS issues in general....but i believe that LNB your referring to is the Linear polarization LNB they are using for the international packages

Why would it "eliminate tree growth issues"? Absorbtion by moist objects is worse at Ka than at Ku.

 

[dragontat002]

I don't know why they feel it would eliminate tree growth issues, I'm sure DTV has an answer for that question though

 

[gbranch]

Where did that bizare "kurz" stuff come from? The lettered microwave band designations were first applied in WWII and were PURPOSELY arbirary and confusing, to keep the other side from knowing what frequency ranges were being used. That is well documented.

I believe that KURZ is German for short, e.g. short wavelength. The band designations came out of the development of radar during WWII. Other bands of interest:

L-band - Radar Long band
S-band - Radar Short band
C-band - Compromise band
X-band - Radar Spot band (X marks the spot)

 

[miguelaqui]

That seller has one of those dishes on you know where, calling it a D* superdish.

It is a lager D* dish with a Ka, possibly Ku, LNB.

Says that it is for sat 95. What are they using sat 95 for in the USA?

 

[dragontat002]

the 95 harbors Vietnamese and Filipino programming as of now...but they are slowly broadening it

 

[k2ue]

I believe that KURZ is German for short, e.g. short wavelength. The band designations came out of the development of radar during WWII. Other bands of interest:

L-band - Radar Long band
S-band - Radar Short band
C-band - Compromise band
X-band - Radar Spot band (X marks the spot)

That's what so ludicrous -- the whole idea was to for the Germans to NOT KNOW what the bands were. Perhaps someone found a description in a contemporary German source, and confused it with German involvement at the onset. This piece of history hast been well covered in the story of MIT RadLabs, etc.

 

[gbranch]

That's what so ludicrous -- the whole idea was to for the Germans to NOT KNOW what the bands were. Perhaps someone found a description in a contemporary German source, and confused it with German involvement at the onset. This piece of history hast been well covered in the story of MIT RadLabs, etc.

It's possible/probable that development in the K-band didn't happen until after the war, and may have even been proposed by one of our captured German scientists. Remember, if it hadn't been for Von Braun and his team of rocket engineers, our space program would have been years, perhaps decades, behind the Russians.

 

[k2ue]

It's possible/probable that development in the K-band didn't happen until after the war, and may have even been proposed by one of our captured German scientists. Remember, if it hadn't been for Von Braun and his team of rocket engineers, our space program would have been years, perhaps decades, behind the Russians.

Well all the bands were named, i.e. given letters, during the war, and there were virtually no captured German radio scientists of any note after the war -- rocket scientists, yes, but not radio. I've been a working RF engineer for 40 years, and am currently a university researcher in RFICs, and this all smells like apocryphal stories to me.

BTW, the Brits invented the Magnetron during the war, and the Americans made it more efficient, but the Germans had squat in high power microwave devices when the war was over, working primarily at VHF with conventional vacuum tubes. Klystrons, TWT's, etc were all US/UK developments.

 

[gbranch]

Well all the bands were named, i.e. given letters, during the war, and there were virtually no captured German radio scientists of any note after the war -- rocket scientists, yes, but not radio. I've been a working RF engineer for 40 years, and am currently a university researcher in RFICs, and this all smells like apocryphal stories to me.

I didn't mean to imply that a captured German radio scientist had named the band, but a generic German scientist. However, if the K-band was named prior to the end of the war, that theory goes out the window.

The names for the bands are all relative anyway. What does short band mean? Short relative to what? Unless the Germans knew the actual operating frequencies, short band, long band, etc. really have no meaning. They could probably deduce that S-band was higher frequency than L-band, but that would be the extent of it. What was UHF 60 years ago is hardly ultra-high today.