This is our old Q&A Site. Please post any new questions and answers at

This may actually be a radiotap question, forgive me if this is going to the wrong place...

I've been seeing a lot of weird 2.4 GHz channels reported, using an Intel wireless card in a Dell, when the only channels in play should be 1, 6, and 11 (and 5, that's a different problem). On the other hand, the 802.11 header reports the "correct" channel. I went around with a Wi-Spy spectrum analyzer and the channels do appear to lie within the frequency ranges they belong in.

AirDefense Mobile seems to be doing the same thing, with a Netgear WNDA3100.

Is this because of the receive sensitivity being good enough for these cards to pick up channels outside the ones they should be tuned to?

asked 11 Oct '11, 13:27

David%20Yerger's gravatar image

David Yerger
accept rate: 0%

What OS are you running on the Dell, what Intel adapter are you using, and what frequencies are being reported?

When you say "AirDefense Mobile seems to be doing the same thing", is it also reporting weird frequencies? (BTW, the only NetGear adapter the AirDefense Mobile page currently mentions is the WAG511.)

(11 Oct '11, 19:27) Guy Harris ♦♦

Or you might wonder how the radiotap header gets filled, where does this information come from? If it's a faulty driver (what else is new) it may report incorrect values, even though the IEEE 802.11 info says the correct values.

permanent link

answered 11 Oct '11, 16:16

Jaap's gravatar image

Jaap ♦
accept rate: 14%

AirDefense Mobile appears to be running on Windows. They run on Windows XP, so they presumably don't depend on Windows Native Wi-Fi, as I don't think that's available in XP, so they might have their own drivers.

Presumably the Dell is not running Windows, as, otherwise, he wouldn't be getting radiotap headers.

So there'd have to be two broken drivers for two different OSes and two different wireless adapters.

(11 Oct '11, 19:25) Guy Harris ♦♦
Your answer
toggle preview

Follow this question

By Email:

Once you sign in you will be able to subscribe for any updates here



Answers and Comments

Markdown Basics

  • *italic* or _italic_
  • **bold** or __bold__
  • link:[text]( "title")
  • image?![alt text](/path/img.jpg "title")
  • numbered list: 1. Foo 2. Bar
  • to add a line break simply add two spaces to where you would like the new line to be.
  • basic HTML tags are also supported

Question tags:


question asked: 11 Oct '11, 13:27

question was seen: 2,646 times

last updated: 11 Oct '11, 19:27

p​o​w​e​r​e​d by O​S​Q​A