HOWTO - Graph signal and noise with karlnet radios

[antagonist]

I figured out how to graph the signal and noise using karlnet radios.
First of all, you need to change the MIBs.
By default, they are backwards.

To change that, just edit the xml file, "<path_cacti>/resource/snmp_queries/kbridge.xml".

Go to: <kbWirelessStationNoiseLevel>
Change the oid from: <oid>.1.3.6.1.4.1.762.2.5.2.1.7</oid>
to: <oid>.1.3.6.1.4.1.762.2.5.2.1.8</oid>

Then Go to: <kbWirelessStationSignalLevel>
Change the oid from: <oid>.1.3.6.1.4.1.762.2.5.2.1.8</oid>
to: <oid>.1.3.6.1.4.1.762.2.5.2.1.7</oid>


Notice the only change was the last number.

The actual values that rrdtool retrieves are the signal and noise in percent.
It took some research, but I finally figured out what karlnet does to convert those numbers into dBm.

The simple equation is: -95 + (MIB value)/2 or -45 - (MIB value)/2.

So, if you have 80% retrieved by rrdtool, the equation is -95 + 80/2 or -55.

So I created a CDEF for the calculation as follows: cdef=CURRENT_DATA_SOURCE,2,/,-95,+

I incorporated the CDEF into the current Graph Template for Karlnet - Wireless Levels.
Also, the template only had current, average, and maximum, so I added minimum.
Then, I made it more readable by making signal an area graph, and noise a line 3 graph.

I created my device and used Karlnet Wireless Bridge for my data template, created the graphs, added them to the tree, and now I have something that I can work with.

I have a nice graph that shows signal in area coming down from the top in blue, and noise as a line a little lower in red.

[gustavoschroeder]

i'm really struggling with my orinoco cards.
how can i make them work, can you please send a step by step howto
thanks in advance
gustavo schroeder

[williamm]

I know that it´s off topic but anybody knows how to convert the xx/158 scale used by Prism 2.5 wireless cards to dBm?