Understanding Lnb Frequency and Transponder Frequencies Essay

1571 Words Sep 24th, 2012 7 Pages
| Understanding LNB Frequencies and Transponder Frequencies « on: April 01, 2008, 07:44:50 PM »http://www.galaxy-marketing.com/satellite-support-forum1/index.php?topic=39.0 | |

These are LNB types and frequencies:

DSS Circular LNB = 12.2GHz-12.7GHz
Standard FSS Linear LNB = 11.7GHz-12.2GHz
Universal FSS Linear LNB = 10.7GHz-12.7GHz

Keeping the above frequency range in mind, now let's look at the frequency ranges of your transponder. Keep in mind that the transponder frequencies are presented in MHz.

All DISH Network, DirecTV, and BEV satellites on DSS have transpnder frequencies that don't go below 12200MHz and don't go above 12700MHz.

All Ku band FSS satellites within North America have transponder frequencies ranging
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However, dishes that are wider than they are tall require a special LNB.
LNBs that are used for satellite TV reception contain DROs (dielectric resonator stabilized local oscillators), which are a ‘pellet’ of material that resonates at the required frequency.
A DRO is relatively unstable compared to a quartz crystal resonator or oscillator.
Tolerances vary by as much as +/- 250 kHz to 2 MHz (Ku band), which include the extremes of the full operating range.
Because most TV carriers are quite bandwidth wide (i.e. 27 MHz band) even a 2 MHz error can successfully be received.
Though PLL LNBs are typically more expensive, the advantage of deploying an external reference PLL LNB is that constant temperature stability is much easier to maintain.
LNB Supply Power
The DC supply (typically in the 13v. to 19v. range) is cable line fed to the LNB and it is often times possible to alter the polarization by changing this voltage.
Alteration via the frequency band is also possible, albeit less common. Efficiently weather proofing the outdoor connector is critical, as oxidation and corrosion occur rapidly. This, in turn, directly relates to signal degradation.
Both the outer and inner conductors must make solid electrical contact.
High resistance causes the LNB to switch permanently into the low voltage state over time, and leads to overall signal deterioration.
If physically trouble shooting a system, be aware that the electrical antenna contacts between the

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