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shadowskippie
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Re: RB751U-2HnD - poor wireless performance & problems

Mon Dec 02, 2013 12:25 pm

Good Afternoon

So, I've done quite a bit of testing with this problem and from what i can see it happens when you add the Wlan to the bridge int. not sure as to why it does this but when i remove the Wlan from the bridge and run it in a routed setup it functions better.

So, this is kind of where a little help is required, the more ppl testing this solution the better.
I took the Wlan out of the bridge, remove the SSID and hid it for good measure.
Then i added a virtualAP to the wireless and setup my wireless SSID there and added that instead to the bridge.

As of typing this it seems to be functioning okay but I've only had this solution running for about a day now.

So, try this solution and see if it helps fix the problem
 
Xcelsium
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Re: RB751U-2HnD - poor wireless performance & problems

Tue Dec 03, 2013 6:32 pm

I tried removing the wlan from the bridge and using it as a router, it help but not too much still getting delay of 2000ms after 5 mins or with 1Mbps Trafic

Doing a more detailed troubleshooting ,changing preamble mode to long and change the HT-TX-chain=0 and HT-RX-chain=1 made to be more stable the communications,

Doing a 5min ping test to my RB951Ui-2HnD with 1 Mbps Download Traffic for 5min result on an average ping of 11ms, a max of 174ms and a min of 0 and a packet loss of 0%


Doint the same test with both TX and RX chain activated with 1Mbps download Traffic got average ping of 108ms max of 947ms and a min of 0ms and a packet loss of 10%

Image

BR
Xcelsium
 
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Re: RB751U-2HnD - poor wireless performance & problems

Wed Dec 04, 2013 6:45 pm

support mail still didnt answer. Maybe any unoficial answer when will poor wifi performance being solved?
 
uldis
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Re: RB751U-2HnD - poor wireless performance & problems

Thu Dec 05, 2013 12:57 pm

we do not suggest to disable the RX for chain0 as you always need to have chain0 RX enabled in order to make stable wireless connection.
We suggest to reset the wireless interface configuration to default values, here is an example command how to do that:
/interface wireless reset-configuration wlan1
 
DeBergz
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Re: RB751U-2HnD - poor wireless performance & problems

Mon Feb 03, 2014 10:27 pm

Do you find any solution to poor wifi perfomance?

I have a RB951G-2HnD and the wifi perfomance is so poor.
On speedtest.net with cable I have 9-11Mbps and on wifi 0.6-2 Mbps.
 
mivan
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Re: RB751U-2HnD - poor wireless performance & problems

Sat Feb 08, 2014 8:18 am

too bad I read this after buying a 751u 2hnd .... my very first Mikrotik =P
just found this because of the same problems described in previous pages

WiFi connection is worse I ever had
 
Fredrik75
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Re: RB751U-2HnD - poor wireless performance & problems

Sun Feb 09, 2014 2:01 pm

I have several RB7* RB9* routers with this problem.
Get at most about 10Mbit download (about 20MBit with cable).

Tried to reset the settings but still the same issue. Tried different channels, 20MHz, 20MHz/40MHz etc but no change...

I have no problem with a product has some flaws in software that can be corrected, but the lack of interest from MikroTik to solve this issue is very strange...
 
hedele
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Re: RB751U-2HnD - poor wireless performance & problems

Wed Feb 12, 2014 1:10 am

Well I found that for the wireless in 751U and 751G to work reliably, I have to disable RX/TX Chain 1, leaving only chain 0 active.
While that limits me to 65 Mbps @ 20 MHz (Real-Life throughput of around 35-40 Mbps), at least the connection is stable.

Enabling TX chain 1 is usually(!) not a problem as well, but enabling RX chain 1 causes all kinds of mayhem. RX signal strength on the 751 flaps around between -80 and -35 dbm with the laptop being less than 3 meters away, RX speed flaps around between 1 Mbps and > 100 Mbps, latency goes through the roof, real-life speeds of around 4 Mbps maximum.

I have had the exact same behavior on three different units, using several RouterOS versions, so I guess there really is something wrong with the MIMO setup in those devices. If free spectrum is available, go for 40 MHz and RX/TX chain 1 disabled. If not, stay on 20 MHz and disable RX chain 1 only. In case that still produces strange problems, the failsafe setting I found that should always work is 20 MHz, RX/TX chain 1 disabled, hardware-retries set to 15. Even more failsafe - but kind of backwards - use 802.11g only. In fact I actually have to use 802.11g only because my Nintendo devices refuse to associate with 751/951 equipment set to 802.11bgn.
 
gammy69er
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Re: RB751U-2HnD - poor wireless performance & problems

Sun May 18, 2014 3:46 am

Well, I am extremely fresh to this whole subject, but as I work for a small ISP that supplies Hotspot Tech to Managed Apartments and Hotels - I have had a major trial by fire over the last 3 months. In saying that - there are a few things I have found - they may help others with their problems.

1. Mikrotik Routerboard wireless appears to be 95% reliable when running - any reliability issues are due to a failing Routerboard - cases of High Ping may be included in this if your ping is greater than 2s (so a std timeout)

2. Mikrotik Routerboards are NOT setup out of the box - you need to configure EVERYTHING you want to use before it will work. Prime example of this is that under "/interface wireless" if you "set ht-amsdu-limit=" to anything below the default max of 8192 (initial thread I read was 256 - I like results with 2048), you will see a marked improvement of throughput. I was getting 22mbps max initially, that increased to 50 - 60 mbps (Clear LOS). The problem is that I get the same results on a 951 with one chain, and here I am using 2 chains on a 751.

3. the reason that I believe I am getting such poor performance on the Wireless - Signal loss under load - I have my RB 1 room away, in a Dark Spot for testing - I get 5 bars signal (sorry for being sooo technical - haven't figured out wireshark yet :/) - 300mbps report rate. As soon as I put load into the unit - drops to 4 bars and jumps between 54, 81, 108 and 121.5 mbps. Now I know that 54 and 108 and single and dual chain "g", 81, could still be "g", but 121.5 is definitely and "n" rate, and is single chain. I also have a Ubiqity Pico M2 HP to test with, and when I have it in the same position as the RB - I get Full Signal, 1 chain 150mbps report - under load - Full signal, 121.5, 150 mbps report - I get 60/70 throughput.

All testing carried out with Btest to router from an i5 750 @ 4ghz PC with N600 TP-Link Usb Stick

so the Morals of my story...
1. Check your settings - make sure that your datarates haven't been disabled for higher rates if you are getting below 15 mbps to router. if you are getting lower, then Hardreset config and start again. Scripting is a good thing to do here. If this doesn't help - try a replacement unit.
2. if you are getting average wireless throughputs - then try changing the Mac layer stuff - I noticed a significant increase in the speeds of the units - for a smaller SoHo or Home/apartment environment, this will become acceptable to most.
3. in saying all this - the wireless is still ****ed. granted, I am not yet MT certified - but when you put a Radio with supposed "27DBm" output - I would expect much better wireless results than a home grade Belkin, for which I do not see... TP-Links are the way to go for regular home users - but I am looking into Ubiquty/RB combos for our business now as the Ubiquty has, as far as I have seen over the last 6 years or retail and corporate sales, the best wireless out there, hands down. The combo you ask, bescause MT still has the best overall system - Powerful, configurable and inexpensive. DD-wrt - just not for me.

Anywho - My question in this whole bit is does anyone know of a way to improve the WiFi, does the external antenna help that much - and if so, does it only help one chain. I know the RB's with add on WiFi work a treat, but cost a little to much for most of our applications.

either way, Cheers - hope this info helps someone.

*EDIT* So I noticed something after further testing - I had the unit set to Regulatory_domain - New Zealand - and although NZ allows for 30dBm, the unit had been restricted to 17dBm - hence my Low Signals - strangely, after restoring to 27DBm - my signal was much higher, but my throughput dropout was far more severe - Dropping to 5.5mbps sync rate and <3mbps data rate. returning my power to ~19dBm returned my throughput to previously mentioned levels - so if signal is not an issue, dropping your Power may help.

In saying that - I had a look at the antenna array and found it to be a little lack lustre - has anyone ever tried reconnecting their own antennas and seeing if that helps the situation - if so, I would recommend reporting it to Mikrotik - they may consider a future model with no internal array and just external connectors.
 
ik3umt
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Re: RB751U-2HnD - poor wireless performance & problems

Mon Jul 14, 2014 10:43 am

In my 2.4 Ghz radioamateur experience, I found many times the receiver saturation leads to a messy quality reception
Some few hundreds meters links made with yagi antennas with huge latency and retransmissions, gone OK only changing antennas with simple low gain dipole (the homemade radios has no TX power regulation capability) to oppose the too strong signal causing distortions on the receiver frontend.

Working with 18-20dbm and over inside a single room, desn't seem a good idea
Think you have to watch a solar eclipse without filtering sunglasses.......

Just my two cents....
Last edited by ik3umt on Wed Feb 18, 2015 6:39 pm, edited 1 time in total.
 
hflack
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Re: RB751U-2HnD - poor wireless performance & problems

Thu Jul 24, 2014 3:56 pm

Anyone able to help me with wireless dropouts? Connection will suddenly drop for a moment then reconnect either automatically or require manual connection again.

[admin@MikroTik @ Hayden's] > /interface wireless export compact
# jan/02/1970 10:37:49 by RouterOS 5.26
# software id = ZPD8-PEXA
#
/interface wireless security-profiles
set [ find default=yes ] authentication-types=wpa-psk,wpa2-psk eap-methods=passthrough management-protection=\
allowed mode=dynamic-keys supplicant-identity=MikroTik wpa-pre-shared-key='' wpa2-pre-shared-key=\
''
add authentication-types=wpa-psk,wpa2-psk eap-methods=passthrough management-protection=allowed mode=dynamic-keys \
name=profile1 supplicant-identity="" wpa-pre-shared-key='' wpa2-pre-shared-key=''
/interface wireless
set 0 band=2ghz-b/g/n channel-width=20/40mhz-ht-above disabled=no distance=indoors frequency=2432 ht-rxchains=0,1 \
ht-txchains=0,1 l2mtu=2290 mode=ap-bridge security-profile=profile1 ssid=MikroTik wireless-protocol=any
 
scampbell
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Re: RB751U-2HnD - poor wireless performance & problems

Sat Oct 18, 2014 1:58 am

These are the settings we use where tablets and Apples are being used.....

1. Use a current RoS
2. Set tx power to 17dBm
3. Use Channel width=20MHz - 20/40MHz is not universally accepted by all devices and uses a lot of spectrum
4. Set distance=indoors
5. Disable TKIP in your security profiles - it limits speed to 54Mbps
6. Set ht-tx-chain=0,1 and ht-rx-chain=0,1 where supported
7. Set Guard Interval=long - allows for slower devices

This has given us stability and happy users.

Handheld devices will look at the signal from an AP and if it is really strong reduce their own power to conserve battery. The result is they may then not have sufficient signal to reach the AP, especially if it's running at 30dBm :lol:

It is best to match your AP capability to that of the devices it serves. So a really strong AP signal may not be serving you well if your client device cannot communicate back to it. It is better to have more low power AP's than 1 big one.

Tablets and iPhones disconnect when they go into standby mode - their wireless shuts down when not in use. Expect frequent re-connections from them.

Lastly, if you are running multiple 2.4 GHz AP's at a site stagger them on channel's 1,6 and 11.

And once you are running reliably you can then "tweak" the settings to see what works best for you.

I hope this helps.
MTCNA, MTCWE, MTCRE, MTCTCE, MTCSE, MTCINE, Trainer
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sb56637
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Re: RB751U-2HnD - poor wireless performance & problems

Tue Mar 21, 2017 5:57 pm

1. Use a current RoS
2. Set tx power to 17dBm
3. Use Channel width=20MHz - 20/40MHz is not universally accepted by all devices and uses a lot of spectrum
4. Set distance=indoors
5. Disable TKIP in your security profiles - it limits speed to 54Mbps
6. Set ht-tx-chain=0,1 and ht-rx-chain=0,1 where supported
7. Set Guard Interval=long - allows for slower devices
...
I hope this helps.
It sure did help! Sorry for necrobumping this thread, but I just wanted to say that #2 and #4 in scampbell's list were the key to *finally* solving major issues with "disconnected, extensive data loss" errors on my network. (In my case, the devices were laptops with Intel WiFI chipsets, not mobile devices.) I've been fighting with this for weeks, and I've tried everything. Especially when doing large file transfers over the LAN with several connections to the same device, it would consistently disconnect after a few seconds to a few minutes, with "extensive data loss" in the logs. According to NetworkManager on the clients, the disconnects were for "reason -4". So I finally ran across this thread, made changes #2 and #4, and after extensive network stress testing I can say I haven't had a single disconnection. Then I reset the WiFI distance to "dynamic" and power levels to "default", and *boom*, a disconnect with "extensive data loss" within less than a minute. Re-applied #2 and #4, and it runs fast and stable. Another added benefit of this change is that my network throughput is almost twice as fast. So thanks again to scampbell!

There are similar suggestions here too: https://gryzli.info/2015/06/20/mikrotik ... rformance/
 
scampbell
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Re: RB751U-2HnD - poor wireless performance & problems

Sun Sep 10, 2017 10:58 pm

1. Use a current RoS
2. Set tx power to 17dBm
3. Use Channel width=20MHz - 20/40MHz is not universally accepted by all devices and uses a lot of spectrum
4. Set distance=indoors
5. Disable TKIP in your security profiles - it limits speed to 54Mbps
6. Set ht-tx-chain=0,1 and ht-rx-chain=0,1 where supported
7. Set Guard Interval=long - allows for slower devices
...
I hope this helps.
It sure did help! Sorry for necrobumping this thread, but I just wanted to say that #2 and #4 in scampbell's list were the key to *finally* solving major issues with "disconnected, extensive data loss" errors on my network. (In my case, the devices were laptops with Intel WiFI chipsets, not mobile devices.) I've been fighting with this for weeks, and I've tried everything. Especially when doing large file transfers over the LAN with several connections to the same device, it would consistently disconnect after a few seconds to a few minutes, with "extensive data loss" in the logs. According to NetworkManager on the clients, the disconnects were for "reason -4". So I finally ran across this thread, made changes #2 and #4, and after extensive network stress testing I can say I haven't had a single disconnection. Then I reset the WiFI distance to "dynamic" and power levels to "default", and *boom*, a disconnect with "extensive data loss" within less than a minute. Re-applied #2 and #4, and it runs fast and stable. Another added benefit of this change is that my network throughput is almost twice as fast. So thanks again to scampbell!

There are similar suggestions here too: https://gryzli.info/2015/06/20/mikrotik ... rformance/
Welcome :-)
MTCNA, MTCWE, MTCRE, MTCTCE, MTCSE, MTCINE, Trainer
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http://www.campbell.co.nz

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