Hi Guys

What indicator do you use when aligning an antenna? normally I check the signal strength and try and get it as strong as possible..However sometimes I get better throughput when the signal is lower..

So do you align by signal strength, CCQ or P-thoughput?

Hi,


if you can have -55 of signal strength and bad CCQ. You have TX and RX signal, you have to consider the 2 signals. And 2 CCQ.

If you have good signal but bad CCQ, try to reduce power of antennas, for example if the APs are very close.

You need to consider all factors.

Hi Martin
I do have same problem but I use 802.11n I mounted p2p link using mpls.
But my tx/rx rate going max 78 Mbit and my signal is -41 to -55 and I use two panels each side with 23dbi . Also the ping between two devices stays like 50 ms
The distance is max 500 to 700 meters.
Any suggestion I really appreciate

thx
Selim

-41 is too good a signal, it damages the receiving end's radio card

hi headstrong
What do you mean with this "it damages the receiving end's radio card"
Do thing one of the cards are bad for what is the problem because the ping is really bad 50 ms to 60 ms. What should I changed it to get it fix to get better tx/rx rate
Also here is my configuration of wireless. Also any suggestion how do I use HT and or any other combination here is my config :


name="wlan1" mtu=1500 mac-address=00:0C:42:3A:E6:EB arp=enabled disable-running-check=no interface-type=Atheros 11N
radio-name="BridgeP2P-1350_to_2100" mode=bridge ssid="p2psouth2" area="" frequency-mode=manual-txpower country=no_country_set
antenna-gain=0 frequency=5790 band=5ghz-onlyn scan-list=5790 rate-set=default supported-rates-b=1Mbps,2Mbps,5.5Mbps,11Mbps
supported-rates-a/g=6Mbps,9Mbps,12Mbps,18Mbps,24Mbps,36Mbps,48Mbps,54Mbps basic-rates-b=1Mbps basic-rates-a/g=6Mbps
max-station-count=2007 ack-timeout=dynamic tx-power-mode=default periodic-calibration=default periodic-calibration-interval=60
dfs-mode=none antenna-mode=ant-b wds-mode=disabled wds-default-bridge=none wds-default-cost=100 wds-cost-range=50-150 wds-ignore-ssid=no
update-stats-interval=disabled default-authentication=yes default-forwarding=yes default-ap-tx-limit=0 default-client-tx-limit=0
proprietary-extensions=post-2.9.25 wmm-support=disabled hide-ssid=no security-profile=default disconnect-timeout=3s
on-fail-retry-time=100ms preamble-mode=both compression=no allow-sharedkey=no station-bridge-clone-mac=00:00:00:00:00:00
ht-ampdu-priorities=0,1,2,3,4,5,6,7 ht-guard-interval=long ht-extension-channel=below-control
ht-supported-mcs=mcs-0,mcs-1,mcs-2,mcs-3,mcs-4,mcs-5,mcs-6,mcs-7,mcs-8,mcs-9,mcs-10,mcs-11,mcs-12,mcs-13,mcs-14,mcs-15
ht-basic-mcs=mcs-0,mcs-1,mcs-2,mcs-3,mcs-4,mcs-5,mcs-6,mcs-7 ht-txchains=0,1 ht-rxchains=0,1 ht-amsdu-limit=8192 ht-amsdu-threshold=8192
hw-retries=4 frame-lifetime=0 adaptive-noise-immunity=none hw-fragmentation-threshold=disabled hw-protection-mode=none
hw-protection-threshold=0


Here is also the int wire reg state

# INTERFACE RADIO-NAME MAC-ADDRESS AP SIGNAL-STRENGTH TX-RATE UPTIME
0 wlan1 StationP2P-2100_ 00:0C:42:3A:E6:78 no -42dBm@HT20-5 65.0... 2d2h2m39s
[admin@Bridge-P2P-1350_to_2100] /interface wireless> reg pr stats
0 interface=wlan1 radio-name="StationP2P-2100_" mac-address=00:0C:42:3A:E6:78 ap=no wds=no rx-rate="52.0Mbps-HT" tx-rate="65.0Mbps-HT"
packets=428697744,339669897 bytes=3264761042,3265778345 frames=174091944,176767521 frame-bytes=2093877788,852867026
hw-frames=197278159,177360309 hw-frame-bytes=4215978033,2050818845 tx-frames-timed-out=0 uptime=2d2h2m50s last-activity=0s
signal-strength=-53dBm@HT20-5 signal-to-noise=59dB
strength-at-rates=-52dBm@6Mbps 11s130ms,-50dBm@9Mbps 2d2h2m49s820ms,-50dBm@12Mbps 2d2h2m49s700ms,-50dBm@18Mbps 2d2h2m49s430ms,-51dBm@24Mbps
1h43s950ms,-53dBm@36Mbps 7m49s60ms,-54dBm@48Mbps 7m43s180ms,-56dBm@54Mbps 1s890ms,-53dBm@HT20-4 1s350ms,-53dBm@HT20-5 0s,
10dBm@HT20-6 20ms,-58dBm@HT20-7 8s660ms
tx-signal-strength=-48dBm tx-ccq=52% rx-ccq=73% p-throughput=50097 ack-timeout=28 nstreme=no framing-mode=none routeros-version="4.1"
last-ip=10.100.252.6 802.1x-port-enabled=yes compression=no wmm-enabled=yes


thx a lot
Selim

Hi Miles

I have not used 802.11n yet so I cannot comment further.

However, I did read on these forums that anything below -40 ( it might have been -50 I cannot remember )is too strong....It is the same principle as looking directly into the sun, it damages your eyes abitilty to receive light and in the long run you will eventually go blind.

i'm looking for the link as a reference but I cannot seem to find it

EDIT: http://forum.mikrotik.com/viewtopic.php ... nal#p61697, this guy also read that -40 is too strong

Hi,

to solve too much signal you need to do the following:

1.- Decrease the TX power of your wireless (interface wireless wlanx txpower..). Default value is "default". The minimum I used is 1. with 0 it doesn't work.
XR5 max is 28, the 100mW cards I think is 17 and 24 is for 400 mW cards.

If this don't solve the too much signal problem:
2.- Use small antennas. If you use 23dBi antennas, try 19 or 16 dBi.

Ibersystems,

Could you just clarify what too strong a signal is? ie stronger than -40 or stronger than -50 etc?

good signal is -55 ... -70, try to keep it within this range.

hi headstrong
thanks for your good advice
Normis I will try to low the power of antennas and I think the signal will go up like around -60 to -70, and I will come back with the resault because right I can't because thet link is on the production netowrk.

thx
Selim

just follow ibersystems steps and you will be fine:)

hi headstrong
headstrong I send the email to support of mikrotik and I got replay from Uldis and he suggest me to change the polarization of antennas and everything is good now.
Thank you all of the help.

thx
Selim

Hi Miles

Thanks for the feedback

Just out of interest, what are your signal levels now? Are both antennas the same polarity or 1x horizontal and the either vertical?

hi headstrong
In both ends I changed polarization of antenna in horizontal. My signal level is from -47 to -49. I did the test one direction I was able to push 96 Mbps but I didn't do it another test because the link is on the production network.
I will try to get any other test like UDP one direction and both direction also TCP .
My tx-power is 13 for the moment and the link distance from 600 top 700 meters .
The only thing I don't like is the ping when the traffic get over 20 Mbps the ping is like 50 ms.
On this like I used:
x2 23dbi Mikrotik flat Panel .
r52n wireless card.
Version of OS 4.1
Device are PC base with dual core Intel Processor.
I hope this is been informed for you ..
If you do need I can send you my configuration to ..

thx
Selim

Hi Miles

I don't think I was clear enought, you have 2x antennas at each end, right? ie 4 in total which equals 2x links/chains..

So was your setup like this:


flat panel------Horizontal polarisation--------flat panel
X86 X86
flat panel------Vertical polarisation-----------flat panel

Or like this:

flat panel------Horizontal polarisation--------flat panel
X86 X86
flat panel------Horizontal polarisation--------flat panel



How many meters were the antennas spaced from each other?

Thanks for the feedback

EDIT: try reduce your tx power to maybee 10 or until the signal is -55...Will be interesting to see if it helps

Hi headstrong
Yes I do have 2x antennas at each end.
Polarization are:

flat panel------Horizontal polarisation--------flat panel
X86 X86
flat panel------Horizontal polarisation--------flat panel

But the ping is very high here it is:
ping 12.10.10.2
12.10.10.2 64 byte ping: ttl=64 time=31 ms
12.10.10.2 64 byte ping: ttl=64 time=26 ms
12.10.10.2 64 byte ping: ttl=64 time=29 ms
12.10.10.2 64 byte ping: ttl=64 time=34 ms
12.10.10.2 64 byte ping: ttl=64 time=28 ms
12.10.10.2 64 byte ping: ttl=64 time=29 ms
12.10.10.2 64 byte ping: ttl=64 time=30 ms
12.10.10.2 64 byte ping: ttl=64 time=21 ms
12.10.10.2 64 byte ping: ttl=64 time=25 ms
12.10.10.2 64 byte ping: ttl=64 time=38 ms
12.10.10.2 64 byte ping: ttl=64 time=35 ms
12.10.10.2 64 byte ping: ttl=64 time=25 ms
12.10.10.2 64 byte ping: ttl=64 time=26 ms
13 packets transmitted, 13 packets received, 0% packet loss
round-trip min/avg/max = 21/29.0/38 ms
This is the ping between two device HotSpot server and GW, and the p2p link this two device each other and traffic is now around 20 to 24 Mbit max.
Any idea why the ping is high. Will help me a lot.

thx
Selim

Hi,

to solve too much signal you need to do the following:

1.- Decrease the TX power of your wireless (interface wireless wlanx txpower..). Default value is "default". The minimum I used is 1. with 0 it doesn't work.
XR5 max is 28, the 100mW cards I think is 17 and 24 is for 400 mW cards.

0 works even negative values they work. some of my links run at -5 which corresponds to around 0.3mW

Hi headstrong
Yes I do have 2x antennas at each end.
Polarization are:

flat panel------Horizontal polarisation--------flat panel
X86 X86
flat panel------Horizontal polarisation--------flat panel

Selim

I would never use two same polarizations on two parrallel radio links. I don´t think this was the advice of MT.

Radio interference is the effect one radio wave has on another and therefore decrease the stability of the radio link.
So 1.
Keep the frequencies of both links as far as apart as possible. Use even two bands (2,4 and 5) is possible. (But not really needed. 5gh band usually has enough freq. available)

2. Space the antenna's as much as possible. Or use very good signal separated dual antenna.

3. Lower the radio power outputs as much as possible but stay in the -55 - -70 range on the receiving end.

4. Make sure you have no other radio's in the area with same frequencies. Run a freq. usage scan before you finally set the link in action.

5. Make sure you have no other radio in close proximity working on high power levels. Special if it works on freqs. your radio is designed for to work with. Some signal can be so strong it penetrates all shields and when the receiver port of your radio opens to recieve signal from its communication partner the signal of the ´intruder´ can create interference and even damage your radio.

5. Make sure antenna's have sufficient free Fresnel zone and sometimes even the fact an antenna is mounted on, or close to, a big reflective (roof, wall, lake, sea, name it) creates interferences. (But actually ´n´ should benefit from this...)

Conclusion, radio connection fine tuning is a matter of many variables. After that comes the fine tuning of the way how data frames are transported over the link with fragmentations, latency, delays, RTS/CTS name it.

Radio signal interferences and the proper fine tuning of all these variables make the final link quality and thus your ping times and throughput.