I recently deployed a simple network for testing purpose, one AP and one CPE, the distance between them is about 300 meters. I launched a ping(ICMP echo) request from CPE to AP. From the statistics of the ping in a few days, It worked fine in most case, received the response from AP within less 5 ms. but it also timed out for over servel minutes sometimes. I wonder if the noise signal interference makes the issue? Is my configuration best?
I'm currently using 917Mhz, its noise floor is -57dbm, others are 907Mhz (-59dbm), 912Mhz(-58dbm), 922Mhz(-58dbm). which channel I should take?

Any ideas would be greatly appreciated!

Here is the descriptions of the equipments and network configuration:

CPE:
MikroTik RB433Ah(v6.1.1), xr9(Ubiquiti mini-pci wireless card),
Mode: station bridge
Band: 2Ghz-B/G
Channel width: 20Mhz
Frequency: 2437
Wireless Protocol: 802.11
Tx/Rx Rate: 18.0Mbps / 5.5 Mbps
Tx/Rx Signal Strength: -74/-92 dbm
Noise floor: -56 dbm
Signal To Noise: -36 dbm
Tx/Rx CCQ: 65/20 %
Overall Tx CCQ: 65%

AP:
MikroTik RB433Ah(v5.2.6), xr9(Ubiquiti mini-pci wireless card),
Mode: ap bridge
Channel width: 20Mhz
Frequency: 2437
Wireless Protocol: 802.11
Overall Tx CCQ: 7%
Noise floor: -68dbm

TX and RX CCQ is verry bad.

Look to the pigtails the cables must not over the radio are.

What type of antennas are being used?

The antennas was home-made, you mean it would be better by using other special antennas?
Could you please tell me where I can buy 900Mhz antennas?

thank you! plisken.

If i helped you, give me karma please, i appresiate this
Thanks

AP reboot abnormally, stations can't make connection,why?
To investigate what on earth causes the disconnections, I make the RB433 and RB411 log to disk file. I found the AP (RB433) rebooted at about 8:00 am today, and the station (RB411) tried to reconnect to the AP since then, and didn't establish the connection until 8:10 am. Another word, it spent 10 minutes reconnect to the AP. I don't know why the AP (RB433) makes so long to reboot?
BTW, I enabled the AP's SNTP client to sync time, but the time server is a PC server on the side of the station, will it make the AP's delay rebooting?

Both RB433AH and RB411 upgrates to ROS v6.1.2.
Any ideas would be greatly appreciated!

Here is the AP (RB433) logs:

ros code

Apr/24/2014 06:33:35 system,info log rule added by admin
Apr/24/2014 06:34:02 system,info system time zone settings changed by admin
Apr/24/2014 14:34:04 system,info system time zone settings changed by admin
Apr/24/2014 14:34:41 wireless,info 00:15:6D:94:CD:46@wlan1: disconnected, disabling
Apr/24/2014 14:34:41 system,info device changed by admin
Apr/24/2014 14:35:04 wireless,debug wlan1: 00:15:6D:94:CD:46 attempts to associate
Apr/24/2014 14:35:04 wireless,debug wlan1: 00:15:6D:94:CD:46 not in local ACL, by default accept
Apr/24/2014 14:35:04 wireless,info 00:15:6D:94:CD:46@wlan1: connected, wants bridge
Apr/24/2014 14:35:42 system,info,account user admin logged out from 192.168.0.150 via winbox
Apr/24/2014 14:38:19 system,info,account user admin logged in from 192.168.0.150 via winbox
Apr/24/2014 14:39:07 system,info,account user admin logged out from 192.168.0.150 via winbox
Jan/02/1970 08:00:19 wireless,debug wlan1: 00:15:6D:94:CD:46 attempts to associate
Jan/02/1970 08:00:19 wireless,debug wlan1: 00:15:6D:94:CD:46 not in local ACL, by default accept
Jan/02/1970 08:00:19 wireless,info 00:15:6D:94:CD:46@wlan1: connected, wants bridge
Apr/25/2014 08:10:35 system,error,critical router was rebooted without proper shutdown
Apr/25/2014 08:39:50 system,info,account user admin logged in from 192.168.0.150 via winbox

Here is the STation (RB411) logs:

ros code

Apr/24/2014 14:35:04 wireless,debug 00:15:6D:94:CD:4B: on 2437 AP: yes SSID ssid917 caps 0x421 rates 0x1 basic 0x1 MT: yes
Apr/24/2014 14:35:04 wireless,debug wlan1: no network that satisfies connect-list,  by default choose with strongest signal
Apr/24/2014 14:35:04 wireless,info 00:15:6D:94:CD:4B@wlan1 established connection on 2437000, SSID ssid917
Apr/25/2014 07:57:52 wireless,info 00:15:6D:94:CD:4B@wlan1: lost connection, no beacons received
Apr/25/2014 07:57:53 wireless,debug wlan1: must select network
Apr/25/2014 07:57:53 wireless,debug empty
Apr/25/2014 07:57:53 wireless,debug wlan1: no network that satisfies connect-list,  by default choose with strongest signal
Apr/25/2014 07:57:53 wireless,debug wlan1: failed to select network
Apr/25/2014 07:57:53 wireless,debug wlan1: delaying scanning
Apr/25/2014 07:57:56 wireless,debug wlan1: must select network
Apr/25/2014 07:57:56 wireless,debug empty
Apr/25/2014 07:57:56 wireless,debug wlan1: no network that satisfies connect-list,  by default choose with strongest signal
Apr/25/2014 07:57:56 wireless,debug wlan1: failed to select network
Apr/25/2014 07:57:56 wireless,debug wlan1: delaying scanning
Apr/25/2014 07:57:59 wireless,debug wlan1: must select network
Apr/25/2014 07:57:59 wireless,debug empty
......【omitted as of duplication】
Apr/25/2014 08:10:08 wireless,debug wlan1: no network that satisfies connect-list,  by default choose with strongest signal
Apr/25/2014 08:10:08 wireless,debug wlan1: failed to select network
Apr/25/2014 08:10:08 wireless,debug wlan1: delaying scanning
Apr/25/2014 08:10:11 wireless,debug wlan1: must select network
Apr/25/2014 08:10:11 wireless,debug 00:15:6D:94:CD:4B: on 2437 AP: yes SSID ssid917 caps 0x421 rates 0x1 basic 0x1 MT: yes
Apr/25/2014 08:10:11 wireless,debug wlan1: no network that satisfies connect-list,  by default choose with strongest signal
Apr/25/2014 08:10:11 wireless,info 00:15:6D:94:CD:4B@wlan1 established connection on 2437000, SSID ssid917

are you using regulat wireless package of wireless-fp package. If wireless-fp package then download the newer test release of the RouterOS v6.13rc7.

are you using regulat wireless package of wireless-fp package. If wireless-fp package then download the newer test release of the RouterOS v6.13rc7.

Would you please tell me how to check which wireless package I use?
I didn't use any third packages by now.

Go to "system" "packages there see you what packages are installed.

The antennas was home-made, you mean it would be better by using other special antennas?
Could you please tell me where I can buy 900Mhz antennas?

Is it possible using home made antennas you could have damaged the radio cards?
Also kemp please only post about 20 lines or so from the logs?

If the self building antenna is not exactly made that can cause damage to your radio card.
Equipment to measure the swr on this frequency is very expensive and not feasible to buy for non-professional people

Go to "system" "packages there see you what packages are installed.

Yes, I checked the packages, it's wireless package of wireless-fp package. I'll upgrade to v6.13rc7 to see if it's fixed.

The antennas was home-made, you mean it would be better by using other special antennas?
Could you please tell me where I can buy 900Mhz antennas?

Is it possible using home made antennas you could have damaged the radio cards?
Also kemp please only post about 20 lines or so from the logs?

In fact, I replace antennas a few days ago, the antennas I'm using is made by ubiquiti,
Antennas:
(Both AP and CPE use the same antennas)
freq: 902-928 MHz
gain: 2x12dBi
VSWR: <1.5Type, Max 1.8
50Ω
2 x N- Female

After using the new antennas, both AP and CPE's performance are improved greatly, as showlng:
AP:
MikroTik RB433Ah(v6.1.2), xr9(Ubiquiti mini-pci wireless card),
Mode: ap bridge
Channel width: 20Mhz
Frequency: 917Mhz
Wireless Protocol: 802.11
Tx/Rx Signal Strength: -62/-56 dBm
Signal To Noise: 21 dB
Tx/Rx CCQ: 100/96 %
P Throughput: 952 kbps

CPE:
MikroTik RB433Ah(v6.1.2), xr9(Ubiquiti mini-pci wireless card),
Mode: station bridge
Band: 2Ghz-B
Channel width: 20Mhz
Frequency: 917Mhz
Wireless Protocol: 802.11
Tx/Rx Signal Strength: -54 / -59 dBm
Noise floor: -72 dbm
Signal To Noise: 13 db
Tx/Rx CCQ: 100/100 %
Overall Tx CCQ: 100%

I wonder why the Signal To Noise of AP is better than CPE's, Is it caused by the improperly way to install the antennas?

Is it possible using home made antennas you could have damaged the radio cards?

you mind me that I set 'Tx Power' to be 'all rates fixed' and 28dBm, would it be damage the radio cards or router board ?

please only post about 20 lines or so from the logs?

Sorry, I will pay attention to that.