Data Alliance’s testing of these two devices side-by-side indicates that AWUS036NH has better range as indicated by its ability to reach more access points than AWUS036H:  AndAWUS036NH is able to reach individual access points with stronger signal.

ALFA ENGINEER agrees that this real-world style testing is more indicative of actual specifications than to use a tool such as NetStumbler to gauge the Receive Sensitivity:  HIS EXPLANATION:  NetStumber is not able to compare them equally, because NetStumber gets the sensitivity information from the device which is AWUS036H and AWUS036NH:   However, AWUS036H and AWUS036NH are using different chipset ~ and different chipset vendor has different way to identify the sensitivity ~ So, if you want to test the units by using NetStumber, it is better to use same chipset model to compare ~

If compare different chipset, my suggestion is to do field, the real environment and try to see the throughtput ~
That will be the fair testing for different chipset device.

Email which prompted the above response from engineer with Alfa:  Email is from Mark Kilty (friend and customer of Data Alliance):

Obviously the prospect of a better USB WiFi unit for us, especially one that also supports N, is huge news.  We have been waiting for an adapter to come on the market that is as good at b/g as the AWUS036H, but with N capability also.  So, we decided to put the two units (AWUS036H AND AWUS036NH) next to each other and do some testing.  Now, we aren’t scientists, and the environment is far from “controlled”, but I think you will find the results interesting.  We also realize that WiFi, although it should be a science, does not seem to be one, and so many factors play in the signals that are received and the quality of those signals.  All this testing was done in only one location, so things might be slightly different in different locations.

We used a tool called NetStumbler, which I assume you are familiar with.  It’s a nice tool to look at the performance of WiFi adapters and compare results.

In this test, we were purely looking at Receive Sensitivity, as we know that the 2W output is an improvement, but if the receive sensitivity drops much at all, the unit is not going to perform as well in the real-world in trying to pick up weak or distant signals.  Based on the specs we have, the AWUS036NH (-92/-76) and the AWUS036H (-93/-76) have almost identical receive sensitivity specs in b/g.

In the following screen shots, the first part of the graph is the AWUS035HN (Transmit: Auto), the second section is the AWUS036NH (Transmit: 50%), the third is the AWUS036H (1watt current model), and the fourth is the AWUS036H (500mw older model).

The first and second sections in the graphs match fine, which we would expect since we are looking at the receive sensitivity, not the transmit power.  You will see a slightly better performance in then 1W vs 500mw versions of the AWUS036H, which we also expect, as you improved the receive sensitivity some with the newer 1W version.  What the surprise is, the very large difference between the AWUS036NH and the AWUS036H.  I am not sure if you folks have done any testing like this before, but would be curious on your thoughts and comments on the performance difference.  I am not an expert at this stuff, but know enough, but perhaps there is an explanation for what we are seeing.  I am hoping so, as I want to continue to be very excited about this new product.