Date: Sun, 04 Aug 2002 23:19:36 -0600 (MDT) From: "M. Warner Losh" <imp@bsdimp.com> To: geekvinod@yahoo.com Cc: freebsd-mobile@FreeBSD.ORG Subject: Re: Comms quality/signal noise stat Message-ID: <20020804.231936.118756968.imp@bsdimp.com> In-Reply-To: <20020805035753.79107.qmail@web21107.mail.yahoo.com> References: <20020805035753.79107.qmail@web21107.mail.yahoo.com>
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In message: <20020805035753.79107.qmail@web21107.mail.yahoo.com>
Vinod <geekvinod@yahoo.com> writes:
: can anybody explain to me a little bit more about the
: Comms quality/signal noise stat appearing with
: wicontrol . it always seems to show [ 0 27 27 ].how
: can this stat be used to monitor the current S/N
: ratio,if it can at all.
The numbers are random. It depends on the card, the firmware and a
number of other things. If you have a lucent card, then you likely
are going to be able to convert them to a dBm at the receiver by
adding -149 to them. However, there are some times that this number
is not valid.
If you are dealing with lucent cards, there's a number of different
ways to convert this number to dBm. Some versions you can add -100 to
the number to get approximate dBm. Other versions you do
-100 + (N * 255 / 100)
other versions do other things. Newer firmware for the prism cards
have a special dBm query you can do (from 1.3 and newer, although 1.0
seems to have some of this functionality).
wicontrol -C automatically subtracts -149 from the numbers. So to
convert them to dBm, you need need to add 149 before doing the above
transform.
Oh, and symbol have numbers that have yet another, different
conversion factor.
Warner
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