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qverty2012
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RB 912 UAG-5hpnd+ Rocket Dish problem with MCS

Fri Aug 22, 2014 11:08 pm

Pls help me with my problem
Have link 27 km There are RB 912 5 + Rocket DIsh from both sides. MCS set manual because otherwise work unstable. So than set MCS 12 ccq link is 100/100 and works very good but cannot receive more that 120 Mb. But when set MCS 13 or MCS 14 ccq link start 99/98 or 97/96 but sometimes go down to 37/70 or less - so have problems with pings and speed. When i reboot the AP and everythinh work. But the situation with foll down ccq is not good and impossible to use MCS 13 or more.

Power set 21 on th eboth sides. Protocol is - NV2
 
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CyberTod
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Re: RB 912 UAG-5hpnd+ Rocket Dish problem with MCS

Fri Aug 22, 2014 11:19 pm

Try selecting MCS12,13,14 at the same time.
If the error rate is low is it will try to stay at MCS14 and if the error rate gets high instead of low ccq it will drop to MCS12 but not lower, because you fixed it to those three.
 
qverty2012
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Re: RB 912 UAG-5hpnd+ Rocket Dish problem with MCS

Fri Aug 22, 2014 11:38 pm

tried set these parametres -work not good - ping is not stable
 
WirelessRudy
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Re: RB 912 UAG-5hpnd+ Rocket Dish problem with MCS

Fri Aug 22, 2014 11:50 pm

Look at the rx signal levels at both end. The higher MCS rates the higher signal or SN they need to work stable. Maybe you just don't have enough signal to noise ratio to get a stable MCS 13 or 14 rate...
Compare the real signals received for each level with the sensitivity needed for each of these mcs levels in the radio.
If there is also some interference source nearby you even need more signal to get better stable link....
 
qverty2012
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Re: RB 912 UAG-5hpnd+ Rocket Dish problem with MCS

Sat Aug 23, 2014 12:27 am

signal to noise is 54
 
WirelessRudy
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Re: RB 912 UAG-5hpnd+ Rocket Dish problem with MCS

Sat Aug 23, 2014 2:52 am

signal to noise is 54
Ok. MCS12 is 16-QAM, where MCS13 & 14 are 64-QAM. To have 13 & 14 working stable you are looking to achieve signal levels in the range of -35 to -45. With an average general background noise level of -105 you are looking for 60 to 70dB S/N.

Actually I have a 9km link with two 30dBi Jirious H+V pol. antennas on both ends and rb911G at both ends (same board basically as your 912).
I have the same issue as you; MSC12 is nice stable with a connection rate of 180Mbps (40Mhz channel and SGI) and a CCQ of close to 100%.
The moment I force both to work with MSC13 or 14 the CCQ drops considerably and the net result is I can 'pump' less traffic over that link (and have more unstable ping time) than in MSC12. So I set 12 fixed and a fall back at MCS10.

My tx/rx signals are -51/-49 seen from AP-bridge unit and only the tx has a fixed CCQ of 100%. The rx which in fact has slightly better signal is continuously running between 97 to 100. (This is actually the 'upload' stream, which usually has less traffic and links with low traffic are always prone to lower CCQ levels.
Ping times are pretty stable around 3ms with an occasional max of 10ms.

So, my link is much shorter than yours. But although my frequency is relative free, there are other frequencies in use just outside the band I set for these units.

I don't know about your link, but I'll guess you have a much more free spectrum that would explain why your link performs as good (or as bad) as mine while you have to bridge a 3 times larger distance...... I don't think you are doing so bad after all! 8)

Like me, if you are really thinking of getting a higher throughput, or a more stable link, I think you might start considering to replace your boards for the new ac boards. I am even thinking of converting it in a triple chain link. This link for me has to start transporting way over 100Mbps in the near future which presently is not achievable.
You have to realize that given speeds (and link stability or latency) are a product of the distance, antennas, radio output and receivers sensibility, free fresnel and state of the used spectrum. Your issue is the sheer distance, mine is the noise level and interferences from other links.

One other think you can do to improve the link is to get yourself bigger antennas. Rocket dish come in 30 and 32dBi models. And the new 30dBi models of MT also look very promising.
 
qverty2012
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Re: RB 912 UAG-5hpnd+ Rocket Dish problem with MCS

Sat Aug 23, 2014 8:29 am

Signal -35 to -45 is too high. Isnt it?
 
WirelessRudy
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Re: RB 912 UAG-5hpnd+ Rocket Dish problem with MCS

Sat Aug 23, 2014 12:10 pm

No, although you don't want it any stronger. But I have several (client) units connected even at -30 and one or two even at -25. They still work fine....
But yeah, I always try to get somewhere between -45 and -60.
 
qverty2012
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Re: RB 912 UAG-5hpnd+ Rocket Dish problem with MCS

Sat Aug 23, 2014 12:58 pm

So should I play with power?
 
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Re: RB 912 UAG-5hpnd+ Rocket Dish problem with MCS

Sat Aug 23, 2014 2:27 pm

Output power can make a difference in certain cases.
 
qverty2012
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Re: RB 912 UAG-5hpnd+ Rocket Dish problem with MCS

Mon Aug 25, 2014 10:17 pm

Only MCS 12 has ccq 100/100.
 
WirelessRudy
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Re: RB 912 UAG-5hpnd+ Rocket Dish problem with MCS

Tue Aug 26, 2014 1:06 am

Only MCS 12 has ccq 100/100.
Sot that's the highest you can get in present configuration. If you want more you do have to change some of the variable you can change.
There is not a lot, power output of radio, gain of antenna (both on both ends), other frequency. And make sure fresnel is free.

One other option I can think of is creating a 3 chain (3 spatial stream) antenna setup and see if you can still get 16-QAM to work, it will give you at least higher throughput (theoretically).
 
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Re: RB 912 UAG-5hpnd+ Rocket Dish problem with MCS

Tue Aug 26, 2014 4:16 am

i swapped 912 board out for 411gl with dbii card and fixed my problems. the 912 board has problems with timing i believe. i had to remove all 6 of them i had installed and havent looked back since.
 
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Re: RB 912 UAG-5hpnd+ Rocket Dish problem with MCS

Tue Aug 26, 2014 11:08 am

the 912 board has problems with timing i believe.
"I believe"? Explain yourself better. Why do think timing is an issue? What does MT say about that? Is this just a problem on some 912 series boards or does it effect the whole production line?
 
qverty2012
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Re: RB 912 UAG-5hpnd+ Rocket Dish problem with MCS

Wed Aug 27, 2014 1:03 pm

I have closer link with SXT+ additional antennas - 10 km.
So I decided to tested this one and change manually MCS - so now works at MSC 14 stable ccq is 100/100 - 6 days.

After that all want to say that possible the problem are in RB 912 - they are not improved
 
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Re: RB 912 UAG-5hpnd+ Rocket Dish problem with MCS

Wed Aug 27, 2014 6:44 pm

the 912 board has problems with timing i believe.
"I believe"? Explain yourself better. Why do think timing is an issue? What does MT say about that? Is this just a problem on some 912 series boards or does it effect the whole production line?
It just seemed like there was something wrong with NV2 to the point it would have excellent ccq until you passed traffic thru it and my gut feeling was the timing of TMDA was off to the point it couldn't sync up well. No scientific data but lots of testing and history behind mikrotik gear - never seen anything like it. Same exact dish pair using other boards fixed the issue every time.
 
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Re: RB 912 UAG-5hpnd+ Rocket Dish problem with MCS

Thu Sep 18, 2014 11:23 pm

Did u try 6.19 with mcs 12 ?

I use to run from 2 years the mcs fixed at 10 and 12 on 40 km link. 100% ccq. 120 Mb peack.
I want to change it with AC board, but 6.19 seems changed the way to set the fixed mcs rate.
 
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Re: RB 912 UAG-5hpnd+ Rocket Dish problem with MCS

Thu Sep 18, 2014 11:32 pm

I have to correct myself. 6.19 and AC board has different user interface.
 
WirelessRudy
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Re: RB 912 UAG-5hpnd+ Rocket Dish problem with MCS

Fri Sep 19, 2014 1:13 am

the 912 board has problems with timing i believe.
"I believe"? Explain yourself better. Why do think timing is an issue? What does MT say about that? Is this just a problem on some 912 series boards or does it effect the whole production line?
It just seemed like there was something wrong with NV2 to the point it would have excellent ccq until you passed traffic thru it and my gut feeling was the timing of TMDA was off to the point it couldn't sync up well. No scientific data but lots of testing and history behind mikrotik gear - never seen anything like it. Same exact dish pair using other boards fixed the issue every time.
OK, I'll put this in the back of my head...
 
qverty2012
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Re: RB 912 UAG-5hpnd+ Rocket Dish problem with MCS

Mon Feb 02, 2015 3:26 pm

Hello. Pick up my topic. Have another ptp link. Distance is 17 km. Use the same rocket dish + Rb 912 uag. This link is shorter than my first (27 km) . So have the same problem. Only great work st MSc 12 ccq is 100/100 . When pick up to MSC 13 or MSC 14 ccq link bavome not stable and in fact have less trought ( only about 80 mb)
So in what is the problem??
 
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Re: RB 912 UAG-5hpnd+ Rocket Dish problem with MCS

Thu Feb 12, 2015 2:00 am

.. rocket dish + Rb 912 uag.. .. When pick up to MSC 13 or MSC 14 ccq link bavome not stable and in fact have less trought ( only about 80 mb)
still a 912 board related issue? (as mentioned above) ..

would someone confirm if it's a possible explanation !?
 
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Re: RB 912 UAG-5hpnd+ Rocket Dish problem with MCS

Mon Apr 20, 2015 9:12 am

.. rocket dish + Rb 912 uag.. .. When pick up to MSC 13 or MSC 14 ccq link bavome not stable and in fact have less trought ( only about 80 mb)
still a 912 board related issue? (as mentioned above) ..

would someone confirm if it's a possible explanation !?
I can confirm this too! Upgraded to this RB from RB433AH+RB52Hn, but this is really related to this board!
 
qverty2012
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Re: RB 912 UAG-5hpnd+ Rocket Dish problem with MCS

Fri Nov 11, 2016 5:39 pm

Hi everybody. Go on my topic with long ling -32km. So - we have change our routerbourds on both side to Netmetal 5. So maximum MCS can set - 12 SIgnal to noise is 55 . If install higher - ccq is not stable. D have any idea how make stable link on MCS 13 or higher?

P.S. is anybody has links with the same distance. I think if use Jiruos antennes, can be better or no?

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