Reception vs Identification Range?

[Guest]

Archived from groups: alt.internet.wireless (More info?)

I have a "Networks Everywhere" 802.11b access point/router.
Kismet can ID it 2-4 times as far away as it can attach to
the network.

Is this disparity normal, or the result of a weak receiver
in the access point?

--
Chuck Forsberg caf@omen.com www.omen.com 503-614-0430
Developer of Industrial ZMODEM(Tm) for Embedded Applications
Omen Technology Inc "The High Reliability Software"
10255 NW Old Cornelius Pass Portland OR 97231 FAX 629-0665

 

[gary]

Archived from groups: alt.internet.wireless (More info?)

"Chuck Forsberg" <caf@localhost.localdomain> wrote in message
newsan.2004.10.24.03.34.47.120343@localhost.localdomain...
> I have a "Networks Everywhere" 802.11b access point/router.
> Kismet can ID it 2-4 times as far away as it can attach to
> the network.
>
> Is this disparity normal, or the result of a weak receiver
> in the access point?

Just as likely a weak transmitter in the client. In order to id the network,
the client only has to be able to receive short beacon frames 10 times a
second. In order to connect, traffic has to go both ways. The router's AP
probably has better antennas and possibly a more powerful transmitter.

>
> --
> Chuck Forsberg caf@omen.com www.omen.com 503-614-0430
> Developer of Industrial ZMODEM(Tm) for Embedded Applications
> Omen Technology Inc "The High Reliability Software"
> 10255 NW Old Cornelius Pass Portland OR 97231 FAX 629-0665
>

 

[Guest]

Archived from groups: alt.internet.wireless (More info?)

On Sat, 23 Oct 2004 20:34:48 -0700, Chuck Forsberg
<caf@localhost.localdomain> wrote:

>I have a "Networks Everywhere" 802.11b access point/router.
>Kismet can ID it 2-4 times as far away as it can attach to
>the network.

Going for the DX record? Kismet and Netstumbler only need to hear a
very small beacon frame to extract the SSID, MAC, S/N, signal
strength, etc. Associating with the same access point requires
considerable negotiation, with packets going back and forth many
times. You could have a truely abysmal S/N ratio coming back from the
access point, and still be able to extract the SSID etc. However, the
same lousy S/N ratio will not work for a full connection.

>Is this disparity normal, or the result of a weak receiver
>in the access point?

1. It could be a weak xmitter on your client radio.
2. It could be interference around the access point is preventing it
from getting a decent S/N ratio *FROM* the client radio.
3. It could be luck that you're getting decent transcient reflections
between the client and the AP.
4. It could be an asymmetrical transmit power, where the AP has a tx
power amplifier, while the client radio uses normal tx power out.
(Think alligator with a big mouth and small ears).

I've seen similar phenomenon using Netstumbler, where I can detect,
but not connect. In most cases, it's #2 because the access point
tends to be mounted in a high location, where it can pickup all manner
of crud. However, I've never seen 2x to 4x differences in range.
Usually, it's about 30% shorter range for a connection. To have such
a large difference, something must REALLY be screwed up. I suggest
you retest with a completely different laptop and radio, to see if the
problem appears to be at the access point end, or in the client radio.


--
Jeff Liebermann jeffl@comix.santa-cruz.ca.us
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 AE6KS 831-336-2558