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Don,

I'm glad I could help! However, I do want to clarify something. The transmit power of the AP and the client card does not have to be equal.

Let's say you have an AP with an output power of 30mw and a client card with the same output power. Will increasing the transmit power of the AP ONLY increase total network range? Yes. That isn't the answer you were expecting is it? :) The reason is this: The AP can hear better than the client card. It has better signal processing and can take advantage of better diversity than most client cards. So, that increases it's ability to receive.

This may sound contradictory to my previous post, but the next part is this: There becomes a point where if you continue to increase the output power of the AP, it will not increase the overall range. After a certain point, the client STA will be so far away that it's TX's will not be heard by the AP, even with it's superior receiving ability.

I'm known for my analogies (not always known for them being good though :) ) so here's one for you.

Imagine a quiet old lady sitting in a rocking chair. At this age in her life, she can't talk very loud or hear very well. Now, take my 5 year old son. He can talk very loud and hears everything.

Now, if he talks to her up close, there is no problems. As he moves away however, he has to talk louder to make up for the distance. Now, since my son has the ability to hear very well like most children, he can hear what she is saying even as he gets farther away.

If he keeps moving away and wants to continue the conversation, one of two things has to happen. Either she has to all of a sudden hear better, or he needs to talk louder. Well, the only "controllable" factor is for him to talk louder. Only my wife has the ability to starting hearing less (different story there :) ). So, as he talks louder, she responds normally. The problem is as he walks away, he can compensate by talking louder, but he can't increase his ability to hear better. So, there comes a time when he is so far away that she can hear him fine (because he is talking so loud), but he cannot hear the responses.

Wow, that was long and drawn out. Anyway, my son is the AP, and the old lady is the client STA. AP's can hear better, so that is why they are allowed to talk louder. But again, there comes a point where talking louder only creates one-way communication.

So here is a summary:

If you have two devices with the equal ability to hear (combination of receive sensitivity and antennas), then one having an increased transmit power will not increase overall range.

If you have two devices with unequal ability to hear (one has better receive sensitivity, signal processing and antennas) then the communication will benefit from that device transmitting at a higher power because it can hear better.

Ok, enough for now. I'm rambling. Please post back if you want to discuss further. I love this stuff!

Gene