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Signal power was increased by the amount of amplification as was the noise floor.
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True, antenna gain will improve the NM; preamp NF will make it worse. But the use of the preamp will improve the System Noise Figure, so I think I am justified in adding the preamp gain as long as I subtract the preamp NF. If you subtract the preamp NF you must also add the preamp gain when considering the whole system, and not just the head end. My original 7777 certainly helped with my crappy signals, with a DB4e, a folded dipole for VHF-High, 50 feet of RG6, and my antenna at 5 feet AGL.
COMPARE System Noise Figures
With and Without Preamps
http://imageevent.com/holl_ands/file...=0&w=1&s=0&z=4
Why do you think it is proper to subtract the harm to the NM that is done by the preamp NF without adding the benefit to the System NF by the preamp gain, its superior NF, and placement at the head of the chain as proved by the Friss Cascaded Noise Figure Equation?
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There's a note to this effect in the signal analysis FAQs.
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Andy Lee also states that in a post:
http://www.avsforum.com/forum/25-hdt...l#post15700679
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Everyone should note that the antenna is the ONLY element in the system that helps you GAIN Noise Margin.
A pre-amp does not change the intrinsic gain of the antenna. Amps boost the signal and noise floor simultaneously, so a crappy signal going into an amp will yield a strong, but even crappier signal (because of the amp's Noise Figure) at its output.
Do not be fooled by lousy antennas that include a built-in amp and claim to be high-gain antennas. The amp's gain does NOT count toward the gain of the antenna itself.
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But if you look at his second image in that post his analysis takes into consideration the harm done to the NM by the preamp NF AND the benefit provided by the preamp gain to turn a negative NM into a positive NM. See my attachment 2.
To put it another way, note that Andy adds the preamp gain at the same time that he adds the preamp NF to the Noise Floor. Why can't I do the same thing?