Community discussions

 
gabriellauter
newbie
Topic Author
Posts: 25
Joined: Mon Aug 27, 2007 11:02 pm

signal to noise

Wed Oct 31, 2007 6:43 pm

guys,

what can be considered a good signal to noise relation?
here I have one access point with client's signal to noise rounding -26db.
in another AP i have clients with -7db!!!... but client's CCQ is ~78%
on this one, the noise floor is -86 dbm, sould us try another channel???

mikrotik versions 2.9.44 and 2.9.46
routerboards with 2.4Ghz mini/pci cards

thanks for any post,

gabriel
 
galaxynet
Long time Member
Long time Member
Posts: 648
Joined: Fri Dec 17, 2004 2:52 pm
Contact:

Re: signal to noise

Wed Oct 31, 2007 8:03 pm

gabriellauter -
Normally you'd like to see about -20db signal to noise ratio. I have seen lower levels that work, like in your case.... If it were me I would look at another channel or two and see if you can get a better S/N ratio.
Thom Lawless
General Manager
RapidWiFi, LLC
thom.lawless [at] rapidwifi.com
 
User avatar
GWISA
Member
Member
Posts: 394
Joined: Tue Jan 31, 2006 2:37 pm
Location: Johannesburg, South Africa

Re: signal to noise

Fri Nov 02, 2007 12:48 am

Around 20dB SNR or better should get you close to the maximum air data rate - depends how much you are pushing through the connection. A lower SNR will mean a lower data rate will be selected.

eg:
snr-mbps.JPG
You do not have the required permissions to view the files attached to this post.
 
quantum
just joined
Posts: 1
Joined: Mon Mar 09, 2009 7:21 am

Re: signal to noise

Mon Mar 09, 2009 8:00 am

Is signal to noise expressed as - or + value?

Here's the average value of one of the SU:

Signal Strength -69 dBm
TX Signal Strength -71 dBm
Signal to Noise 30 dB
Tx/Rx CCQ 45/55%

At this moment, the link of SU to AP is still quite good and the througput is between 1 - 3 Mbps average.

Can anyone try to explain whether this value is good enough to sustain a reliable connection?
If not, what should we improve?
 
User avatar
roc-noc.com
Forum Veteran
Forum Veteran
Posts: 869
Joined: Sun Dec 02, 2007 3:27 am
Location: Rockford, IL USA
Contact:

Re: signal to noise

Mon Mar 09, 2009 9:04 am

Is signal to noise expressed as - or + value?

Here's the average value of one of the SU:

Signal Strength -69 dBm
TX Signal Strength -71 dBm
Signal to Noise 30 dB
Tx/Rx CCQ 45/55%

At this moment, the link of SU to AP is still quite good and the througput is between 1 - 3 Mbps average.

Can anyone try to explain whether this value is good enough to sustain a reliable connection?
If not, what should we improve?
Your snr is just fine. But your CCQ is terrible. Try another channel. CCQ should be above 75% and the closer to 100% the better.
If you don't see any improvement in CCQ on other channels then you probably do not have clear enough LOS.

Tom
-----------------------------------------------
http://www.roc-noc.com
Tom, CCNA, ISP, USA Mikrotik Distributor
888-762-5662
-----------------------------------------------
 
User avatar
GWISA
Member
Member
Posts: 394
Joined: Tue Jan 31, 2006 2:37 pm
Location: Johannesburg, South Africa

Re: signal to noise

Mon Mar 09, 2009 9:14 am

Is signal to noise expressed as - or + value?
SNR is + value
a - value means you are in the noise floor.

If your CCQ is not good, then as roc-noc.com said, your LOS is probably no good. You could be picking up a reflected indirect signal, multipath interference, or there is a partial obstruction in the path.
 
wireless12
Member Candidate
Member Candidate
Posts: 295
Joined: Fri Aug 31, 2007 10:49 am

Re: signal to noise

Mon Mar 09, 2009 2:02 pm


Here's the average value of one of the SU:
Signal Strength -69 dBm
TX Signal Strength -71 dBm
Signal to Noise 30 dB
Tx/Rx CCQ 45/55%

At this moment, the link of SU to AP is still quite good and the througput is between 1 - 3 Mbps average.
how did u calculated the throughput of AP and SU.?
 
User avatar
kameelperdza
Member
Member
Posts: 469
Joined: Thu Nov 27, 2008 11:45 am
Location: Oudtshoorn, South Africa

Re: signal to noise

Sun May 08, 2011 7:36 pm

Hi there is 42db signal to noise to loud? I managed to reduce tx power on some link to make signal to noise between 19 and 30.

What is the highest that signal noise can be before it is considered as shouting.

cheers
Give me some karma
 
WirelessRudy
Forum Guru
Forum Guru
Posts: 3089
Joined: Tue Aug 08, 2006 5:54 pm
Location: Spain

Re: signal to noise

Tue May 10, 2011 11:54 pm

Hi there is 42db signal to noise to loud? I managed to reduce tx power on some link to make signal to noise between 19 and 30.

What is the highest that signal noise can be before it is considered as shouting.

cheers
Any s/n above 20 is good. But if the value becomes very big (30, 40 or even more) this only means the signal itself is very strong. Signals stronger than -40dB should be avoided. Lower could even lead to damage to the reciever.
In areas with many radio signals and many multipath reciept, if all transmitters are sending with too much power than actually needed you create high noise levels and more interferences. By lowering outputs of radios you smoothen this so go low as long as your s/n doesn't fall below mentioned 20.
Show your appreciation of this post by giving me Karma! Thanks.

Rudy R. Puister

WISP operator based on MT routerboard & ROS.
 
User avatar
BlackFate
just joined
Posts: 23
Joined: Fri Aug 10, 2012 2:22 pm

Re: signal to noise

Fri Dec 14, 2012 8:15 pm

Hello, and sorry to bring this up again.
I bought a new wireless adapte for my desktop and my SNR is 57db.
Im about 10 metres away from my tik with 2 doors between.
Should i lower the strength signal of my adapter?

Who is online

Users browsing this forum: No registered users and 24 guests