Hello,
we are testing (only testing) a link with a distance of 11 Kms with the following materials:
- RB133 + 13 dbi 900 Mhz Yagi antenna + XR9 (like bridge)
- RB133C + 13 dbi 900 Mhz Yagi antenna + XR9 (like station WDS)
the situation is like Near line of sight to non line of sight (the antennas are outdoor).
the problem is that in our country the 900 MHz band is used for GSM Handys,so i think very noisely,but the cards detect a -93 dbm noise floor ????
and we don't have any connection
the link is only fortest purpose, how is it possibleto see if connection is possible please ?

Make sure you have the right antenna port selected and are using one of the supported channels. 5mhz spacing will give you slightly stronger signals. Also, use horizontal polarization if vertical is too noisy. I have a non line of sight link around 15km with a 12 dbi antenna on one end and 18dbi yagi on the other. If you do get a signal and need a little more, try the 18dbi's on each end. That would give you a total improvement of 12dbi, which is a big difference.

Joe

Did you test the units could communicate when close together before installing? If not, I suggest you take them down and test them when only a couple of metres apart. It's much easier to diagnose problems with the units close together than having to do it with the units many Kms apart! At least that way you eliminate configuration problems, after that it's usually other external factors that influence whether you get a connection or not.

Hello,
thanks for the answers, yes we have tested the units before mounting (30 meters without any line of sight, indoor use) and it gives -17 dbm signal power.
i think i will use horizontal polarisation instead of the vertical.
one thing, we use 2.4 GHz only g, do you think we must use other thing? (such 5 Mhz).
are the cavity filters helpful in this situation ?
thanks again for your help

My experience with 2.4GHz is forget it unless you have clear line of sight.

No, we use XR9, so 900 MHz Band. But the card is reconized as 2.4 Ghz card.

Couple of points.

First is that SR9/XR9s will not see non-802.11 noise at all. So you are right, its probably VERY noisy but you aren't seeing it on the noise floor indicated by the cards. A Canopy or Trango 900 SU makes a good, inexpensive spectrum analyzer as they both display all noise in the band.

Second, if you are running a 900 AP in an area with lots of 900 GSM, you are probably going to be pretty unpopular when the authorities catch up with you. Licensed carriers tend to take their (expensively obtained) priviledges pretty seriously. Penalties vary depending on where you are but can be substantial...

George

This is my experience with a test link in urban area. Now I have link up but only passing 3 MB TCP. Waiting for filter.. Closest GSM is around the 850's then starts back around the 929's..

http://forum.mikrotik.com/viewtopic.php?f=7&t=19910

I think if you set the cards to B only and switch to horizontal polarization you'll be fine.

B only took my link that dropped at 12, 3 and 5 (at 5 and 10MHz channel) and made it stable. Hardware retries to 7 helped quite a bit as well.

10 and 5Mhz channels are a variant of 802.11G
I have a 900Mhz link using SR9s running through 1500' of thick forest and it only works in B, but it runs at 2mbps. S/N of only 4-6.