1. LNB selection
    1. Definition / description
      1. An LNB is a combination low-noise amplifier and block downconverter.
      2. It converts the feeble 3,700 to 4,200 MHz satellite signal into a stronger 950 to 1,450 MHz signal which is easier to send over coaxial cable.
    2. Meaning of technical specs
      1. Meaning of "digital ready" and "phase locked loop"
        1. Phase Locked Loop
          1. Of these three phrases, only "phase locked loop" has an engineering definition. A phase locked loop (PLL) oscillator makes an LNB’s frequency output as stable as it can be made at reasonable prices.
          2. Wegener strongly recommends PLL LNB’s for use with its receivers and so does ABC.
          3. Typical stability at C-band is ± 10 to ± 50 kHz with phase noise 75 dB below carrier at a 1 kHz offset from the carrier.
          4. Expect to spend about $400 for a C-band PLL LNB.
        2. Digital Ready
          1. "Digital ready" LNBs are sometimes marketed as being "second best" to PLL (and one step lower in price).
          2. A review of catalog numerical specifications indicates that the phrase "digital ready" has no significant meaning.
          3. Some have stabilities as poor as ± 350 or ± 500 kHz with phase noise 65 dB below carrier at a 1 kHz offset.
          4. They sell for $150 to $350.
      2. Meaning of noise temperature spec
        1. If you remember seventh grade physics, you were told that, at any temperature above absolute zero (0° K), the atoms within any substance are vibrating. In electrical circuits, vibrating atoms cause random signals, called "noise." In the low-noise amplifier stage of an LNB, specially-designed transistors are employed to produce a noise output that would be generated by a specific reference material at a specific temperature above absolute zero. This reference point provides a translation between noise and temperature.
        2. Typical LNBs are designed for noise temperatures between 20° K and 80° K at C band. Any of these noise temperatures are good enough for ABC reception.
        3. If you still have an LNB at 120° K or 150° K, it's worth a few hundred dollars to replace it. Keep the old one on a shelf as a spare. It's cheap insurance.
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