technology is documented
The local oscillator is inside the LNB, so a Ka band LNB would have an 18+ghz LO, producing the usual range for our existing receivers to deal with.
Just the same way any typical FTA receiver does C-band and Ku-band.
The receivers really receive 950 - 2150mhz , as down-converted by the LNB.
They just do the math if you give them the LO, and
tell you they are receiving at 3800 or 12000 mhz
Since they were never meant to receive Ka band, they probably won't do the math at Ka frequencies (try and see if you can put in an 18ghz LO).
So, early experimenters might want to put in more traditional LO frequencies, and use a calculator to figure out where you are actually receiving.
Another point in question, is this: are the Ka band LO below or above the incoming frequency.?
I'd assume below, but if you get it wrong, you'll be tuning backwards across the band.
I remember reading about the LNBs on the DirecTV dish, somewhere.
I think it was in the installation instructions for the AT9 (now discontinued*) dish on the SolidSignal site.
They have a
5 video set you can watch, for alignment instructions.
(look directly under the picture of the dish)
edit: from the video -
DirecTV Ka sats are at 99º & 103º
down link freq range: 18.3 to 20.2ghz
converted freq range going to receiver: 250-750mhz, 950-1450mhz, and 1650-2150mhz
the 250-750 mhz is outside the range of FTA receivers.
the Ka output uses the 250-750mhz and 1650-2150mhz range
sounds a lot like bandstacking to me.
*
discontinued means some have shown up at the dump -
TurboSat already has his!