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GTHill Escribi?3:

I think both of you make very good points. Before I stick my foot in my mouth again, I am going to do some experiments to see how amplification on either end affects data rate, range, etc.

Would you say that an amplifer does not increase the receive sensitivity of the amplified device?

This is undeniably true. The receive sensitivity of the device is a quality of the chipset itself and is essentially fixed. Now, a receive amplifier CAN boost the strength of an incoming signal, which creates an effect similar to having higher receive sensitivity, but it's not exactly the same thing.

If you have an AP with 100mw of power and you add a 12dBi antenna with no amplifier, will that increase the overall range even if the client cards are not changed?

Absolutely. The principle of antenna reciprocity says, in short, that a high-gain antenna receives just as well as it transmits. All other things being equal, adding antenna gain increases range regardless of the transmit power of the two devices. The catch is that increased gain results in more focused signal, so there may be practical limits on the amount of gain that a system can employ, depending on where coverage is required. This is why I generally prefer to use higher-gain antennas in a client-access network, as opposed to amplifiers. My second choice is to employ radios with higher receive sensitivity. Amplifiers are my last choice in a client access network. On the other hand, I'm more likely to use amplifiers in a point-to-point link or mesh network, where all devices can be equipped with amplifiers.