Hello to all,
Which is one good Signal Strength value and Which is critical Signal value for one alignment?
for example:
-30db is ottimal Signal Strength
-60db is a good signal
-100db the bridge can’t work
I don’t know the generic correct range of good signal.
thank you
Well here is my beleif to be a good signal
20db Best you can get
30 db VERY VERY GOOD signal
50 db very good signal
60 db good signal
70 db good signal but getting bad
80 db Not super but better than nothing
90 db Can you spell headache?
100 db RIP
Well thats what i think, IM sure others will have different veiws, but wireless is a weird thing.. and can be very different in differencet sircumstances.. Well good luck. -Jordan
from my experience the best signal is in range -60…-70 and i do my best to keep the clients in this range.
I agree.
Try to have all clients between this range. It is due to WIRELESS card. When it is between -50 to -90 the card get something like saturation and pings, and speed goes down.
In my experience, signal levels stronger than -40 often cause problems. At -50 I get 54Mb, at -38 I get 18Mb.
Its kind of like someone talking to you. There is such a thing as too loud.
i get 54mbps and at -74…
I consider anything less than -72dB is not good.
Signal should be at least 20 to 22 dB stronger than noise level.
Huh thats interesting. I get 54MB at 35db… I dont know.. good to know though..
Thank’s for replay.
There is a report between signal and nosie?
In Winbox, in the wireless status page on the client side, below the noise floor. On the AP, go to wireless, registration, then signal, SNR is on that page as well.
SNR is just the difference between signal and noise. If signal is -60, noise is -90, SNR is 30.
This is a value that help me to aligin the mikrotik? the noise must be in relationship with siganl?
for example: the nose should be at least 40bd than signal.
Thanks
Except in odd situations, your noise level will stay about the same when lining up the antenna. Noise around here is about -96 in the 900MHz band. What will change will be your signal level. It will get better as you line up your antennas. For a reliable link, you want your signal level about 20dB stronger than the noise.
Hie guys am meeting the same problem signal found is in the range of 75-79dbm signal to noise 20dbm tx ccq varies =35-85…rx ccq varies 35-75 running at 5300 mhz but the signal keeps on droping 1st after 15 hrs then after 15 minutes and now 35 minutes its still running…router board r411
Sounds like you have fresnel zone problems or interference on that channel.
Thee easily measurable attributes for a link would be signal, noise, and the recieve sensitivity.
Signal will tell you how powerful the signal you are recieving is.
Noise will tell you how much background chatter there is. (I find this reading useless in RouterOS. For example I can put two 5 GHz antennas right next to each other on the same channel and transmit on both and they will still read as no percieved noise yet they will interfere with eachother. I tend to use a spectrum analyzer if I suspect a noise issue. I also consider background noise different then interference.)
A wireless cards recieve sensitivity will tell you how much signal you have above the minimum for a specific data rate. For example the R52H has a recieve sensitivity of -70 @ 54 Mbps. This means with a signal of -65 and a noise floor of -90 you would have a reported SNR of 25 dB which is decent, but only a 5 dB margin at maximum data rates.
My rule of thumb for a stable link has been SNR >25 dB and a minimum 12 dB margin @ your desired data rate. I am not saying links can’t work outside of this, but I have found that they will drop/disconnect much more often.
Cheers
From my investigation with 802.11n cards, they simply don’t read any noise value, it´s always -105~117dB, even with another device on the same channel. Driver issue?
To achieve 64-QAM 5/6 (54Mbps), the signal should be ~30dB better than noise. And here comes the problem, if the noise that was read is not real, they will choose a wrong modulation scheme. A couple of hw-retries will happen, eventually it will start jumping between modulations (data-rates), reducing the overall bandwidth. And this happens very often.
Mikrotik way of solving this issue: select data-rates manually
I do-not agree with this approach. The radio should be able to read the real noise, and adapt to the conditions signal vs noise, and not just the signal received.
My way to find noise is to add the mikrotik device to dude, do a spectral scan on dude, and see what appears on the tabs waterfall and density.
If you need a stable high speed link, first scan to find noise that you have, then put your link running and see your signal levels. If you can guarantee 30dB from signal to noise, you will have a stable link, otherwise you will have to disable the higher data-rates. And the signal should be less that -50dBm, or it will be too strong, and not less than the value specified on the data-sheet to accomplish that data-rate.
Final: If the data-sheet states that with 54Mbps minimum signal is -74dBm, and your real noise is -96dBm, 96-30=66
Your signal should be at least -66dBm to be able to work reliably with 54Mbps.
My two cent’s.