andira123
Posts: 23
Joined: Tue Nov 24, 2015 2:25 pm

wifi signal in wavemon raspberry pi

Mon Apr 24, 2017 7:06 am

Hi, I'm trying to see my wifi signal strength using wavemon. I've googled about dBm levels are around 0 ... -100 dBm. But why is my dBm around 10 ... 19 dBm. I'm confused. because I want to convert it to it's RSSI and I do not know how to convert a positive dBm into it's signal level in RSSI.

thank you

davef
Posts: 64
Joined: Wed Feb 20, 2013 8:39 pm
Location: Christchurch, NZ

Re: wifi signal in wavemon raspberry pi

Mon Apr 24, 2017 8:27 am

10 to19dBm is more like a transmitter power level. I don't understand how it could measure that unless antenna gains and path loss it known.

Check again that it is setup correctly.

davef
Posts: 64
Joined: Wed Feb 20, 2013 8:39 pm
Location: Christchurch, NZ

Re: wifi signal in wavemon raspberry pi

Mon Apr 24, 2017 8:46 am

https://en.wikipedia.org/wiki/Received_ ... indication
There is no standardized relationship of any particular physical parameter to the RSSI reading. The 802.11 standard does not define any relationship between RSSI value and power level in milliwatts or decibels referenced to one milliwatt. Vendors and chipset makers provide their own accuracy, granularity, and range for the actual power (measured as milliwatts or decibels) and their range of RSSI values (from 0 to RSSI maximum)

andira123
Posts: 23
Joined: Tue Nov 24, 2015 2:25 pm

Re: wifi signal in wavemon raspberry pi

Mon Apr 24, 2017 9:51 pm

it's hard to calculate because dbm fluctuates up and down. Do all raspberry pi shows this? I read some forums and someone said that raspberry pi's dbm are positive number.

I also want to ask will it be the same result of dbm if I use my dongle on my laptop and in my raspberry pi? will I get the same result in certain places when using the dongle for my laptop and my raspberry pi?

davef
Posts: 64
Joined: Wed Feb 20, 2013 8:39 pm
Location: Christchurch, NZ

Re: wifi signal in wavemon raspberry pi

Mon Apr 24, 2017 10:13 pm

Any RSSI implementation will probably show variations. Try walking between the Raspberry Pi and your WiFi router and watch your readings. I think there are some time issues to consider when doing this, ie how long it takes to update the RSSI reading.

Variation might be reduced by taking several readings and averaging them, but then you won't get updates very often.

Is there some published relationship between the dongle's RSSI reading and the received signal level in dBm?
Last edited by davef on Mon Apr 24, 2017 11:05 pm, edited 1 time in total.

davef
Posts: 64
Joined: Wed Feb 20, 2013 8:39 pm
Location: Christchurch, NZ

Re: wifi signal in wavemon raspberry pi

Mon Apr 24, 2017 10:16 pm

Show the links to a positive dBm signal level.

RSSI is a positive number. You can map a range of negative dBm signal levels to a representative positive RSSI reading.

If you use the same dongle in both situations and they are in the exact same physical location and nothing has changed in the environment I would expect the same readings. The RSSI level is measured in the dongle.

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