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<span style="font-family: Calibri; font-size: 11pt; font-weight: bold;">From: </span>
<span style="font-family: Calibri; font-size: 11pt;">Steve Shipway <</span><a href="mailto:s.shipway@auckland.ac.nz" style="font-family: Calibri; font-size: 11pt;">s.shipway@auckland.ac.nz</a><span style="font-family: Calibri; font-size: 11pt;">></span></div>
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<span style="font-weight:bold">Date: </span>Tuesday, May 5, 2015 at 6:26 PM<br>
<span style="font-weight:bold">To: </span>Rick Silacci <<a href="mailto:rick@velociter.net">rick@velociter.net</a>>, "<a href="mailto:mrtg@lists.oetiker.ch">mrtg@lists.oetiker.ch</a>" <<a href="mailto:mrtg@lists.oetiker.ch">mrtg@lists.oetiker.ch</a>><br>
<span style="font-weight:bold">Subject: </span>Re: [mrtg] Measuring RSSI<br>
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<p class="MsoNormal"><span style="color:#1F497D">You’re returning the SNMP OID rssi.0<o:p></o:p></span></p>
<p class="MsoNormal"><span style="color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="color:#1F497D">Can you do an SNMPwalk from the command line, and retrieve this – it may be that the OID returns the value as a positive integer, or in a different form to how you expect? You may need to modify your Target
line to do some sort of post-processing (for example, some devices return temperature as an integer in centidegrees Celsius, and so need to be divided by 10 (or even converted to Farenheit in certain unenlightened countries:))<o:p></o:p></span></p>
<p class="MsoNormal"><span style="color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="color:#1F497D">You do not give the entire MRTG configuration stanza here for comparison, but I’ve seen it in a separate communication, so I can verify that you do not have the ‘bits’ option enabled (which would multiply by
8).<o:p></o:p></span></p>
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More than likely, the units are centiBels. You can fix that for display using Factor[] 0.1</div>
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<p class="MsoNormal"><span style="color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="color:#1F497D">Also, by default, MRTG assumes positive values. If using RRDTool as the backend, you need to manually tune the .rrd file to allow negative values; I think they might be rejected by native mode MRTG.<o:p></o:p></span></p>
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Correct. I have to tune my radio readings with:</div>
<div><font face="Calibri,sans-serif">for k in *signal.rrd ; do rrdtool tune $k –I ds0:-800 –I ds1:-800; done</font></div>
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<p class="MsoNormal"><span style="color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="color:#1F497D">Steve<o:p></o:p></span></p>
<p class="MsoNormal"><span style="color:#1F497D"><o:p> </o:p></span></p>
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<p class="MsoNormal"><b><span style="color:#1F497D">Steve Shipway<o:p></o:p></span></b></p>
<p class="MsoNormal"><span style="font-size:10.0pt;color:#1F497D"><a href="mailto:s.shipway@auckland.ac.nz"><span style="color:blue">s.shipway@auckland.ac.nz</span></a><o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:1.0pt;color:#1F497D">(GNU Terry Pratchett)<o:p></o:p></span></p>
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<p class="MsoNormal"><span style="color:#1F497D"><o:p> </o:p></span></p>
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<p class="MsoNormal"><b><span lang="EN-US" style="font-size: 10pt; font-family: Tahoma, sans-serif;">From:</span></b><span lang="EN-US" style="font-size: 10pt; font-family: Tahoma, sans-serif;"> mrtg [<a href="mailto:mrtg-bounces+s.shipway=auckland.ac.nz@lists.oetiker.ch">mailto:mrtg-bounces+s.shipway=auckland.ac.nz@lists.oetiker.ch</a>]
<b>On Behalf Of </b>Rick Silacci<br>
<b>Sent:</b> Wednesday, 6 May 2015 11:11 a.m.<br>
<b>To:</b> <a href="mailto:mrtg@lists.oetiker.ch">mrtg@lists.oetiker.ch</a><br>
<b>Subject:</b> [mrtg] Measuring RSSI<o:p></o:p></span></p>
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<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal"><span class="a"><span lang="EN-US">I’m using the parameters below to measure rssi. I’m supposed to be getting a negative number expressed in decibels, but this is what I’m getting:<o:p></o:p></span></span></p>
<p class="MsoNormal"><span class="a"><span lang="EN-US"><o:p> </o:p></span></span></p>
<p class="MsoNormal"><span class="a"><span lang="EN-US"><o:p> </o:p></span></span></p>
<p class="MsoNormal"><span class="a"><span lang="EN-US">Variable </span></span><span class="l"><span lang="EN-US">Name: RSSI</span><o:p></o:p></span></p>
<p class="MsoNormal"><span class="a"><span lang="EN-US">Variable </span></span><span class="l"><span lang="EN-US">Description: Radio Signal Strength<o:p></o:p></span></span></p>
<p class="MsoNormal"><span class="l"><span lang="EN-US">Index</span></span><span class="a"><span lang="EN-US" style="letter-spacing:-.75pt">SNMP/MRTG Variable
</span></span><span class="a"><span lang="EN-US">Name rssi.0</span><o:p></o:p></span></p>
<p class="MsoNormal"><span class="a"><span lang="EN-US">Example: Target[Var]:rssi.0&rssi.0:Canopy@MyDevice:::::2</span></span><b><span style="font-size: 10pt; font-family: Arial, sans-serif;"><o:p></o:p></span></b></p>
<p class="MsoNormal"><b><span lang="EN-US" style="font-size: 10pt; font-family: Arial, sans-serif;"><o:p> </o:p></span></b></p>
<p class="MsoNormal"><span class="a"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-US"><img border="0" width="500" height="135" id="Picture_x0020_1" src="cid:image001.png@01D087EF.84044430"><span class="a"><o:p></o:p></span></span></p>
<p class="MsoNormal"><span class="a"><span lang="EN-US"><o:p> </o:p></span></span></p>
<p class="MsoNormal"><span class="a"><span lang="EN-US"><o:p> </o:p></span></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size: 9pt; font-family: 'Arial Black', sans-serif;">Rick Silacci</span><span style="font-size: 9pt; font-family: 'Arial Black', sans-serif;"><o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size: 9pt; font-family: 'Arial Black', sans-serif;">Velociter Wireless<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size: 9pt; font-family: 'Arial Black', sans-serif;">1525 Second Street<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size: 9pt; font-family: 'Arial Black', sans-serif;">Escalon, CA 95320<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size: 9pt; font-family: 'Arial Black', sans-serif;">Office: 209.838.1221<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size: 9pt; font-family: 'Arial Black', sans-serif;">Phone: 209.838.1800<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US"><o:p> </o:p></span></p>
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