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Orinoco Gold card, NS 0.3.3, W2K Pro SP4. TCP/IP off.

Usually I've noticed a good association between NS's SNR (as shown via the graph) and the signal strength shown on the client manager signal strengh 'meter'.

In this situation, NS shows a 'top of the green' reading of about -85 dbm, with the solid green around -90, and the green/red margin at about -100. What's interesting (given it's a slow day here) is that the client manager will just barely elk out one red bar, indicating the signal is close to unreadable.

This seems odd, since on other signals that are weaker than this one, i.e. 'top of green' around -70, I can get nearly five solid green bars on the client manager meter.

My first thought was that the AP in question must be a 802.11a device. But since the card is a 'b' device, then NS shouldn't be showing a signal at all. Or is it more versatile that I thought?

Thanks.

Originally posted by heartland
...
In this situation, NS shows a 'top of the green' reading of about -85 dbm, with the solid green around -90, and the green/red margin at about -100. What's interesting (given it's a slow day here) is that the client manager will just barely elk out one red bar, indicating the signal is close to unreadable.

This seems odd, since on other signals that are weaker than this one, i.e. 'top of green' around -70, I can get nearly five solid green bars on the client manager meter.

...

The figures and graphs are right, you're just reading them wrong. You need to learn to how to read deciBels (dB). First of all, -70dBm IS better than -85dBm. dB are measured in negative numbers. The red line (typically around -95dBm to -100dBm in most places) is the Noise Threshold or Noise Floor; the point at which signal is indistinguishable from the background RF noise.

Actually, at a 15dB difference, -70dBm is a 500% increase in signal strength over -85dBm. Every 3dB is a doubling (100%) in signal strenth.

-90dBm, at only 5dB to 10dB above noise, is a poor signal.

Read through the Antenna FAQ threads. This is explained in more detail and there are some links to white papers on deciBels.

I don't need to learn how to read dbm's, I DO however need to learn to pay attention when I'm typing.

My numbers in my earlier post were backwards. The -85 signal (per NS) is the one that gives me 4 out of 5 green on the client manager. The -70 signal is the one that gives me one very short red bar on the client manager. Thus, the 'better' signal (as shown by NS) is just showing a short red bar, while the lesser signal (of which there are many) are showing strong signals in the client manager.

Playing around with it awhile ago, I surveyed five local signals (with my, uh....'laboratory' AP off). Here's what happend:

Signal per NS Signal per Client Manager

-100 dbm one short red bar (no surprise here)

-75 dbm four to five green bars

-85 dbm three to four green bars

-70 dbm four to five green bars

-70 dbm one short red bar (the subject of this post)

FYI, I'm using a catenna (not the pringles...one made with a larger can).

Pardon me reading my notes wrong, I know nobody likes to waste time with reading nonsense posts. For that I apologize.

I'll certainly take a look at the Antenna FAQ.

Thanks.