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Convert Signal Strengh from % in dBm

Is this possible? is there a convertion table?

bernhard

3 REPLIES
Bronze

Re: Convert Signal Strengh from % in dBm

There is a way to see the signal strength on the ACU in dBm instead of percentage. The following is taken from this URL

http://www.cisco.com/univercd/cc/td/doc/product/wireless/airo_350/350cards/windows/legacy/icg/win_appf.htm#55539

Step 1 Double-click the Aironet Client Utility (ACU) icon on your desktop to open ACU.

Step 2 Click the Preferences icon or select Preferences from the Options drop-down menu. The Aironet Client Utility Preferences screen appears.

Step 3 Under Signal Strength Display Units, select one of the following options:

Percent—Displays the signal strength as a percentage.

dBm—Displays the signal strength in decibels with respect to milliwatts.

--------------------------------------------------------------------------------

Note dBm can be selected only if your client adapter is using PCM/LMC/PCI card firmware version 3.92 or greater, mini PCI card firmware version 5.0 or greater, or PC-Cardbus card firmware version 4.99 or greater.

Re: Convert Signal Strengh from % in dBm

sorry i forgot to write that i need the conversion an a VxWorks Bridge in the assosiation table.

sorry =:-)

bernhard

New Member

Re: Convert Signal Strengh from % in dBm

I think what's been asked many times in these forums, but never answered is, "How does one convert a dBm value into a Cisco Aironet % value?". We *know* how to configure the ACU to display dBm or % values, but how do the two values correlate to each other?? We are looking for a formula of the form:

% = f(dBm), where f() is a function

Or, provide a table. My *unscientific* conversion table (done by switching between dBm and % readings on a fluctuating signal) is:

dBm %

---------

-80 30

-70 50

-60 66

-50 88

>-45 100

Again, the values were obtained by my reading the ACU Site Survey values on an Aironet AIR-PCM352 card; these values have not been calibrated nor were they obtained in a controlled scientific manner. What we would like is to know the *official* Cisco conversion formula or be provided with a conversion table. The Cisco percentage value is some proprietary thing Cisco created for signal strength readings on the Aironet, as RF Engineers ALWAYS work in dB. Unfortunately, non RF guys seem to like % values

To qualitatively assess the signal strength, here's my DBm assessment compared with Cisco's % assessment

Description % dBm

-------------------------------

Excellent > 80 > -55

Good 40 to 80 -72 to -55

Fair 20 to 40 -84 to -72

Poor < 20 < -84

So, will a Cisco Aironet Engineer please provide us with a proper conversion table to replace mine above, or else MY tables could become the de facto standard!! That would truly be scary.

Thanks

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