I purchased some range extender antennas for a Linksys WRT54GS v4. They are advertized as 9dbi. They are something like this (probably exactly like these)
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Perhaps they provide that much gain, but I tend to doubt it. They did provide about a 4 or 5% signal strength improvement at 100 feet.
My problem/question has to do with noise. DD-WRT reports -100 noise for all of my clients and an average signal to noise ratio of 21 to 27 for them all as well.
Would the increased gain of the antennas also pick up a heavy increase of noise, or is it more likely that the antennas are not properly tuned and are actually the cause of the noise?