Sorry, this is gone due to exhusted storage. I'm rewriting it...

LNA: Low Noise Amplifier. Original Microwave head end device.

Cable has a practical limit of 2000 ... 4000 MHz (2...4GHz). At higher frequencies often waveguides are used. These are hollow round or rectangular "pipes" that work a little bit like fibres do for light.

So when microwave receivers changed from Valves and Travelling wave tubes to transistor circuits, becoming easier to power and minaturize the logical step was to put more of the receiver at the Dish focus, so the Local Oscillator to the First I.F. frequency was put inside the receiving horn, the LNB, which stands for Low Noise Block.

Different Kinds

If the switch for Horizontal or Vertical is built in, it is operated by changing the supply voltage from 12V to 18V (nominal).

If the LNB is for Digital, or multiple Frequency bands on Analog, a 22KHz tone is used to select the High or Low band.

If it was for original TV Satellites the LO will be 10GHz for 10.950 to 11.700 GHz band.

To be continued....