i have a mikrotik client connecting to a mikrotik Ap.first the wireless network was working fine suddenly it keeps diconnecting
every 5 to 10 mins.
the client side is a grid antenna with an R52n card.distance from AP 4km. i get a signal 0f -79 to 80.
what can be the problem?

thanks

What is your ccq? Are you using Nstreme or NV2?

am not using nstreme. client side its on station mode.

signal strength -77dbm
tx signal strength -82dbm
signal to noise 24db
tx/rx ccq 59/43%
Pthroughput 13849 kbps

AP frequency is 5300

am not using nstreme. client side its on station mode.

signal strength -77dbm
tx signal strength -82dbm
signal to noise 24db
tx/rx ccq 59/43%
Pthroughput 13849 kbps

AP frequency is 5300

Link quality is very poor in the first place, also see other trend on this issue:
http://forum.mikrotik.com/viewtopic.php?f=7&t=49493,
http://forum.mikrotik.com/viewtopic.php?f=13&t=49321

I think your low signals are your problem.
Give us more info on your setup, like:
dB of the antenna
coax in use and what length and self made or manufactured
LOS?
Fresnell?
Some pictures would do or a sketch. Also, google on some "path loss calculator" or "Fresnel calculator" to see how your link should be.

Even for a small grid I have for 3km links already some 10dBm higher signals minimum.

If you say your link worked well before you have to ask yourself if some environments might have been changed. Like the weather, humidity. Obstructions in the LOS? (Truck, tree with/without leaves.)
And maybe interference of other radio's? Do a wireless scan and see if you pick up close channel radio's.

Also, give us your radio config's. Together with all this other info we might be able to give you more help.

thanks for the reply earlier on.

i have changed the card in the enclosure to XR5 frequency at 5300,connecting to 24dbi grid antenna.
this is set in station mode.

my AP is running also on an XR5 connecting to an omni.at first frequency was at 5300 but seem more people are
using that so i changed to 5240.
checking my signal from AP side its like this:

signal strength -76dbm
Tx signal strength -78dbm
signal to noise -22db
Tx/Rx CCQ 74/71

the setup at the client side is we installed a 15m pole the grid is at the top.the ground in low that side so we can't see
the AP.we tried to get the signal thats the one i've said.their are a couple of big trees with leaves not directly in front.
and as of the weather its just started getting too hot.

thanks for the reply earlier on.

i have changed the card in the enclosure to XR5 frequency at 5300,connecting to 24dbi grid antenna.
this is set in station mode.

my AP is running also on an XR5 connecting to an omni.at first frequency was at 5300 but seem more people are
using that so i changed to 5240.
checking my signal from AP side its like this:

signal strength -76dbm
Tx signal strength -78dbm
signal to noise -22db
Tx/Rx CCQ 74/71

the setup at the client side is we installed a 15m pole the grid is at the top.the ground in low that side so we can't see
the AP.we tried to get the signal that's the one i've said.their are a couple of big trees with leaves not directly in front.
and as of the weather its just started getting too hot.

Well, that explains a lot. 5Ghz band is a real LOS so antenna's need to see each other. For some longer distance it even needs to be with a sort of ´free tunnel´ between both end. Anything in this sort of tunnel (Fresnel, but more ´belly´ shaped) disrupts the signal by distorting the signal and thus high package losses. If the antenna's can't even see each other its even worse. You will only get low signals but even so, the link is also very unstable. Apart from heavy package losses (low CCQ) you'll probably also see the signal fluctuate a lot.

If there is really no other way to set the antenna's (maybe one in-between that can both others?) than you'd better try to use 2,4Ghz because it has slightly better NLOS characteristics.

thanks every much

wirelessRudy

how would one know when their is an interference from others radio's.what should one look for?
how would you trace the problems.

As concerning my link i have setup my AP on 5240 frequency and its been connected for almost 14hrs hope it keeps up.
i had to run a snooper and found that the frequency of 5300 i used at first was being used by a couple of people.

wirelessRudy

how would one know when their is an interference from others radio's.what should one look for?
how would you trace the problems.

As concerning my link i have setup my AP on 5240 frequency and its been connected for almost 14hrs hope it keeps up.
i had to run a snooper and found that the frequency of 5300 i used at first was being used by a couple of people.

Best would be to have a scan with a spectrum analyser. But they are quit expensive. It will show every signal that is interfering with your frequency of choice. No matter if this is another wifi or a microwave or other source emitting radio energy.

Second option is to run a wireless scan (winbox / Interface / Wireless / scan) in both 20Mhz and 10Mhz bandwidth. It will show you which other users of same or adjacent channels there are.

Effects of interferences can be; low CCQ's (<60) when there in itself is enough signal (better than -85) and high noise levels (> -100->-90).
You might also notice that the noise floor level is fluctuating some db's.
Depending on the chosen working mode for the wireless adapter (NV2, nstreme, 802.11) you will also see disconnects... This is actually the best sign interference might be an issue.

thanks again