I have searched the forums but could someone point me to the purpose of a preamp/amp??? The way I understand it is that the amp is to overcome long cable runs so the signal does not degrade. Is this right???
A pre-amp can help with a few things. First it can set and improve the overall noise figure of your system. Improved noise figures equate to improved reception in fringe areas with low signal levels. The system noise figure will equal the noise figure (NF) of the first amplifier the signal sees and it seems that there are external amplifiers with lower NFs than the amplifiers inside of most commercial receivers and STB. Yes, the first thing inside every modern reciever or STB is a another integrated pre-amp.
Secondly, because of their gain, the external pre-amp can effectively negate any losses that the signal encounters on its way from the antenna output to your STB input. They include cable loss, signal splitters and surge suppressors. Without the external amplifier, these losses would detract directly from your signal level.
In areas with consistintly strong signal levels the pre-amp can result in worse reception because they can be overloaded by nearby RF sources and generate distortion. It's generally best to get a higher gain antenna first to solve reception problems and an external amplifier only when necessary.
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