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When capturing wireless packets the data rates listed by the capture program should be what was sent by the station and not some other lesser value as you move away from the transmitter correct? Maybe corrupt packets are playing a role just odd that a lot of neighboring networks show up with lots of packets in the 12Mbps or lower range. I understand management/control frames are sent at lowest common rate. I guess with internet access and basic file/print sharing the end users will never notice it.

Thanks,
Mike

Hi Mike,

[quote]When capturing wireless packets the data rates listed by the capture program should be what was sent by the station and not some other lesser value as you move away from the transmitter correct[/quote]

Absolultely. Consider an AP and STA talking to each other at, say, 270 Mbps. When you're close to them (a few meters), your Wi-Fi packet capture program will show virtually all the packets being sent or received. The percentage of damaged packets (i.e. the ones with bad FCS) will be low. As you move farther away, you will see the percentage of damaged packets increasing, but the data rate shown by the program for these packets would still be 270 Mbps. At some point, when you're a few dozen yards away (depends on the environment), you will see virtually no packets, because packets sent at high rates are hard to capture when you're far away.

Now, if your STA is far away from the AP, it will talk at a much lower data rate, e.g. at 27 Mbps. Your capture program must reflect that fact, and as you move farther away with your monitoring notebook, you will notice that low rate packets can be "heard" much better than high rate packets.

That's how it is supposed to work in a good Wi-Fi monitoring program, like CommView for Wi-Fi (commercial) or Wireshark+AirPcap (if you prefer open source and you're crazy enough to waste $700 on an AirPcap USB adapter that actually costs $50:-). If your monitoring program works differently, then there is something terribly wrong with it. For example, Microsoft NetMon can capture Wi-Fi packets, but it will show you nonsense instead of the real 802.11n rates.

Regards,
Dieter

Thanks Dieter.

[quote]At some point, when you're a few dozen yards away (depends on the environment), you will see virtually no packets, because packets sent at high rates are hard to capture when you're far away.[/quote]

The light bulb came on with that comment, I am most likely just not seeing the other packets due to corruption etc.