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Message: [QUOTE="Rickideemus, post: 115445, member: 12677"]Ouch! That's pretty brutal, Stever. :bolt:rbf, On the amp situation, I thought of this way of explaining it:You want to install an amplifier as close to the antenna as possible because you want to amplify the cleanest signal possible. You would prefer not to amplify noise added by long cable runs and splitters. Since a TV has its own amplifier, if you could attach a TV directly to an antenna with no cable, theoretically an amplifier would provide no benefit whatsoever, no matter how weak or choppy the reception. In fact, most amplifiers are guaranteed to degrade the signal on undivided cable runs under 30 feet, because they add their own noise to a system.Some more sources:<a href="http://www.hdtvprimer.com/antennas/basics.html">Antenna Basics</a>"Never feed an amplifier output directly into another amplifier.  There should always be a long cable between the preamplifier and [any] distribution amplifier.  Placing the two amplifiers close together can cause overload and/or oscillation.... Many people think that connecting an external amplifier to the antenna will improve the performance of the antenna.  This is usually wrong.  Receivers always have more gain than is necessary.  (The receiver has an Automatic Gain Control circuit, AGC, which will reduce strong signals.  The AGC makes all stations the same strength at the demodulator.  When you add a preamplifier, the TV receiver lowers its own gain, usually by an equivalent amount.)Normally the signal to noise ratio will be set by the receiver’s first transistor.  But if an external amplifier is added, the first transistor in that amplifier determines the S/N ratio.  (Since the external amp will greatly magnify its own noise as well as the signal, the receiver’s noise becomes insignificant.)  Since there is no reason to think the external amp’s first transistor is quieter than the receiver’s first transistor, there is generally no benefit to the S/N ratio from an external amplifier.But an external amplifier will compensate for signal loss in the cable [and any splitters -- Rickideemus] if the amplifier is mounted at the antenna.  Without this amplifier, a weak signal, just above the noise level at the antenna, could sink below the noise level due to loss in the cable, and be useless at the receiver."<a href="http://en.wikipedia.org/wiki/Preamplifier">Preamplifier - Wikipedia, the free encyclopedia</a>"A preamplifier (preamp) is an electronic amplifier that prepares a small electrical signal for further amplification or processing. A preamplifier is often placed close to the sensor to reduce the effects of noise and interference. It is used to boost the signal strength to drive the cable to the main instrument without significantly degrading the signal-to-noise ratio (SNR). The noise performance of a preamplifier is critical; according to Friis's formula, when the gain of the preamplifier is high, the SNR of the final signal is determined by the SNR of the input signal and the noise figure of the preamplifier."<a href="http://en.wikipedia.org/wiki/Low-noise_amplifier">Low-noise amplifier - Wikipedia, the free encyclopedia</a>"Low-noise amplifier (LNA) is an electronic amplifier used to amplify possibly very weak signals (for example, captured by an antenna). It is usually located very close to the detection device to reduce losses in the feedline... An LNA is a key component which is placed at the front-end of a radio receiver circuit. Per Friis' formula, the overall noise figure (NF) of the receiver's front-end is dominated by the first few stages (or even the first stage only)... Using an LNA, the effect of noise from subsequent stages of the receive chain is reduced by the gain of the LNA, while the noise of the LNA itself is injected directly into the received signal. Thus, it is necessary for an LNA to boost the desired signal power while adding as little noise and distortion as possible, so that the retrieval of this signal is possible in the later stages in the system. A good LNA has a low NF (e.g. 1 dB), a large enough gain (e.g. 20 dB) and should have large enough intermodulation and compression point (IP3 and P1dB). Further criteria are operating bandwidth, gain flatness, stability and input and output voltage standing wave ratio (VSWR)."<a href="http://winegard.com/kbase/kb_tip_results.php?tip_num=480">Winegard - Which Preamplifier is Right for me?</a>"The most important thing to know about preamplifiers is that they do not pull in signal or extend the range of TV antenna. If we do not have a good strong enough signal at the antenna a preamplifier will not help. The function of a preamplifier is to amplify the TV signal received by the antenna and strengthen the signal so that you can over come your cable loss, splitter loss, etc that is between the antenna and your TV set. The gain of the preamplifier determines the amount of loss that you can over come."<a href="http://www.antennacraft.com/Antennas/AntennaAmplifiers.html">Antennacraft Pre-Amplifiers</a>"More amplification is not always better. The sole purpose of an amplifier is to offset signal loss due to long cable runs (over 75'), splitters, multiple TVs or other factors."Rick[/QUOTE]

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