5. 11g / Super-G overlap

Figure 6 shows another spectrum analyzer composite shot supplied by Atheros.

Figure 6: Super-G and normal 11g signal overlap (from Atheros)

This time, it shows normal 11g signals on channels 1 and 11 and a Super-G "static turbo" signal centered on channel 6 from a WLAN approximately 35 feet away from the normal 11g devices. The amount of overlap between the normal 11g and Super-G signals would have more clearly illustrated if all had been plotted at the same distance so that all peak signal levels were equal, but this is what Atheros supplied.

Figure 7: Super-G and normal 11g signal overlap (from Broadcom)

Broadcom's shot in Figure 7, though, shows a full-strength Super-G signal overlapping into drawn-in markings for channels 1 and 11 so that you're sure to see that the Super-G signal is pretty much at full strength when it first overlaps into both "non-overlapping" channels.

A few notes about Super-G:

Super-G has dynamic (auto) and static modes. Static mode is intended to be used in all Super-G WLANs and kicks in all of Super-G's features, including channel bonding. Super-G mode is centered on channel 6 and can't be moved. Dynamic mode is intended to be used in mixed WLANs and takes into account the types of stations (clients) in the WLAN and their bandwidth demands. The Super-G signal shown in Figures 6 and 7 is what you'd see in static mode or dynamic mode under maximum bandwidth demand conditions.

So now we've established a second key point:

Key Point #2: Under similar range and bandwidth demand conditions, Super-G signals can have a greater degree of overlap into channel 1 and 11 than a normal 11g channel 6 signal.

With those points in mind, it's now time to put them to the test.