D-Link (DWL-AG520) Signal Strength conversion

[maverickmax]

Hi

I am using DWL-AG520 as part of my experiment and I look into the manual for information about signal strength but it does't tell you that much. Bascially I want to use dBm instead of percentage but I cannot configure it in the D-Link software setting. So I need to know how to convert signal strength percentage to dBm but I am not sure how to do it.

Please help me

Maverick Max

[masraum]

I have a Dlink DWL-G520, and the signal strength that is reported by the Dlink software is double the value that is reported by Netstumbler.

so when Dlink says 88% netstumbler says 44 dB. Can't say that either is right, but that's my experience.

[Phoenix]

Receive signal strength will generally be in the range of -90dBm to -20dBm. Many of the chipset manufactures have utilities that can give you the actual RSS value in dBm, Your device has an Atheros chipset, so you might want to check with them.

[maverickmax]

Phoenix

Indeed, I found out that most D-Link products esepcially DI-774 and DWL-AG520 use AR5001X+ chipset (Atheros). Also I have found that RSSI_Max for Atheros is 60 and subtract 95 from it to derive dBm. But i remain sceptial because I cannot confirm that 60 is the max of RSSI and where 95 come from? I have attached the URL with this thread, please check this out:

http://www.wildpackets.com/elements/whitepapers/Converting_Signal_Strength.pdf


In the mean I am trying to find the datasheet for AR5001+ in www.atheros.com at the moment

Maverick Max

[maverickmax]

Here is a list of D-Link products that currently use Atheros the chipset - AR5001X+

http://customerproducts.atheros.com/customerproducts/ResultsPageBasic.asp

Good news is that I have the datasheet of AR5001X+ but it didn't mention RSSI_Max or dBm:

Maverick Maxhttp://www.atheros.com/pt/ar5001X+.html

*Arrgh*

Maverick Max

[masraum]

I can't directly answer your question, but today I found something you might find interesting if you don't already have it...

Site with drivers (http://www.star-os.com/downloads.php#freestuff)
this is what you're looking for on the page.
VNC CM-9 (Atheros AR5004) Windows Drivers
v2.4.2.33
v3.3.0.150 (Bleeding edge BETA - use with caution)

On this page is a pair of generic Atheros drivers that will provide more info. I had the Dlink software, then got Netstumbler, then today installed these drivers. This driver reports much more info than either the Dlink utility or Netstumbler. It reports the signal as RSSI and as a negative number, and it also reports noise (but in my case the noise is around -101 -- -104 unless I stick my cordless phone next to the antenna, then it goes down). So it seems as if this driver may provide better info.

Something that I've noticed, Netstumbler seems to report the difference between the two values that the driver reports. I moved my antenna to see what the numbers would do and when netstumbler reported 44 the driver is reporting -59 and -103.

[masraum]

This may or may not be good news, but this morning I've noticed that I am getting some different noise numbers. I've seen the noise vary from -104 to -98 dB. Still not sure if that's accurate, but it's something.

[ccrum]

Unfortunately there is no standard for converting any given mfg's "quality" measurement to anything real. It is a very subjective thing. First what are they giving a percentage of? Singnal strength, S/N, some combination of the two? My guess is that this won't be documented anywhere that the general public would have access to it. I'd use the values you get out of Netstumber and forget the percentages you see in the driver. Better yet, if you are doing a lot of measurement work, get a good tool like a Yellow Jacket or similar, or even a good old fashioned spectrum analyser. You'll save yourself a lot of guess work.

[maverickmax]

Dear Steve

Thank you for your valuable information.....

I will let you know soon if these software are useful


Kind regards

Maverick Max

[spiderbite]

I know that 10 x LOG(power in mW) = dBm

So if you can some how get percentage to mean something in mW, maybe this might help.

The Cisco ACU has all that in there and I have noticed that when I am in the neighboorhood of 40% signal strength, I am in the neighboorhood of 20dBm.

[FlaWireless]

Spider,
40% in the neighbor hood of -20 dbm?
I think you might want to check that again.
I just did a test to be sure, and I was at 90% and I'm reading -50 dbm.

[spiderbite]

Hmm, let me see if I didnt screw up...

Link (stupid) meter says 40% signal strength - Signal quality can be anywhere 80-90%

Go back to survey tool and My signal to noise ratio is about 20db

-ish.

Thats what i meant to say, and please forgive me if thats not what you heard.....

Thats why I don't usually play with the link meter much...

I need dBm or I have no idea whats going on....

[FlaWireless]

I agree, it's almost like without dbm I'm lost.
To get the reading I was just talking about I was looking at the site survey portion of the Cisco ACU. First I looked at the signal using dbm the went to preferences and changed my setting to % (I never use %) and checked it again and those where the numbers I recieved.

[maverickmax]

Hi

I have tried to use the Atheros software and I admit I remains sceptical of using it because I don't know if this software is right for DWL-AG50........

What I would like to see that D-Link confirm that Atheros Utilitiy software can be used for most of D-Link products. Unfortunately D-Link didn't reply to me. Therefore I have no choice but use percentage signal strength as part of my experiment.

In the mean time, I am still looking for different approach to convert percentage into dBm.

I would be very happy to hear any feedback from you

Maverick Max

[masraum]

I understand you're wanting to know if the atheros drivers will work. I had a copy of the dlink drivers handy when I did my upgrade just in case. You can determine which chipset your AG520 has on the Dlink website, and then you can read through this thread to see how interested you are in the atheros drivers. Just a note, some people had a problem with the gina.dll being changed which caused a problem with their fast user switching. I never did.

http://www.dslreports.com/forum/remark,10663595~mode=flat

[maverickmax]

Hi

I have been using Atheros Utility software during my series of experiments but I want to raise two issues regarding this software and measurement.

I understand that maximum signal should not exceed than 20 dBm in Europe. Can anyone explain me why I get approximately 43 dBm reading from utility when I put the transmitter precisely 1 meter away from Receiver? It is above the legal power unless I have done something wrong.

I have checked the LinkMon software and it said the Wireless DWL-AG520 PCI’ was being used but it did not mention ‘AR5001X+’.

Do I need to copy AR5001X+ driver? If yes, where from?

Maverickmax

[masraum]

The Atheros drivers and utilities list my card as a Dlink DWL-G520 rev B, so I would not expect it to list yours as the atheros chipset number.

About the dB reading that you are getting. I can't explain it, but I bet there's something going on. Does your scale start at -100 or does it start at 0? I'm not sure about the regs in Europe, but do they say the signal can't be higher than 20 dB or -20 dB? Either way I bet that is assuming the signal starts at -100. If you are showing 43 then it is probably a fluke of the driver and is actually assuming a start from 0. Mine used to start at 0 and go up from there. With the Atheros drivers and utility my RSSI is reported as a positive number starting at 0, but with the Atheros drivers and Netstumbler my signal starts at -100 and goes up from there.

I don't think you have anything to worry about.

[maverickmax]

Steve

The scale didn’t start from -100 or 0 dBm but 40-summat at the distance from transmitter and receiver.

In the meantime I try not to worry about it…..


Maverickmax

[masraum]

No, what I meant was if you get completely out of range and you are receiving no signal what is the number, what is the minimum reading? I'm guessing 0. That's unusual, the scale usually starts at -100. These Atheros chipsets seem to report weird and don't always start at -100. I only got mine to start at -100 by installing the atheros drivers and then going into netstumbler and selecting the NDIS device. Now it starts reading at -100 and goes up from there.

[maverickmax]

Steve

Your prediction is correct....the reading is 0 when the communication link is out of the range.

In fact the receiver sensitivity is -73 dBm and it would be great for me to read from -73 dBm up to whatever. So I would like to use Netstumbler. Can you please tell me more about Netstumbler and NDIS?

So i can give it shot for my experiment

Cheer

Maverickmax

[masraum]

www.netstumbler.com

http://forums.netstumbler.com/forumdisplay.php?s=&forumid=20

http://forums.netstumbler.com/forumdisplay.php?f=4

http://www.netstumbler.com/download.php?op=viewdownload&cid=1&orderby=hitsD

that should be all you need.