MikroTik

We found 2 of our SR2 cards (2.4G) give clients very slow speed if they connect on 11b (150kbps), but high speed if they connect on 11g (2-3mbps). I don't see this on the SRC cards.

Are those cards malfunction on 11b and ok on 11g (thus, need to be replaced)?
Or is this a common problem with SR2 cards?

Urgend help required, as we need to decide to replace with other SR2 or change back to CM9.

Are you sure its not a path problem?

802.11g is much better at multipath, there are several situations here where G is reliable and B doesn't work at all.

G works in my shop, metal building, 200ft away, B doesn't work at all, even with higher power levels. Same thing out past the trees. Out in the open, I get better signal with B with poor signal levels.

We took Laptops to the location and verified it.
Connecting on 11b... signal excellent, thruput 200kbps
Connecting on 11g... signal excellent, thruput >3mbps
We replaced the SR2 with an SRC (its a RB230) and
11b jumped up to 3mbps as it should.

We have this on 2 locations already, and basiclly either replace SR2 or switch them in a G-only mode.

Question is, does anyone has issue on 11b with SR2?
Can someone confirm that our 2 cards are probably 11b-broken ?

another 2 SR2 started to slow on 11b clients.
Do I have just a faulty set of cards, or does anyone else have problems with SR2 cards on 11b clients (while 11g clients are fine) ?

Anyone?

I'm betting on enviromental. Something interfering with DSS, OFDM is better in that respect as well.

but why the CM9 and the SRC doesn't have that problem?
It happen only with SR2 cards

but why the CM9 and the SRC doesn't have that problem?
It happen only with SR2 cards

I ran into the same problem. I found that one client was causing the problem. His shot was marginal and the one tree grew just enough to cause problems. My best educated guess is that the better Rx sensitivity combined with the output power of the SR2 help to make it worse. It is not the cards fault I put up a client that was marginal - but now I have to fix it. For the time being all is running well on mixed mode - but we are working to clear the problem for good.

...
Question is, does anyone has issue on 11b with SR2?
Can someone confirm that our 2 cards are probably 11b-broken ?

sr2 works fine in G and B. but if you read specification sheet of the card, it's easy to see that if you have a good signal str., sr2 can transfer much more traffic in G. in B card can better convey traffic if signal str. is very poor, e. g. -93dBm and and more.

regards,
C. G.

honestly, I've never seen the sr2's specification sheet.
We have several clients who use Smartbridge's Airbridge (11b only). They get good signal strength; perhaps too good? they now get about 100-200kbps (before on CM9 they got 2-3mbps).
Since we replaced CM9 by SR2, our problems started.

Are you running that SR2 at max output? It's current requirements and the available current on the miniPCI slot of a 230 are right at the edge. Try backing the power off to 200 or 300mw as a test and see if performance improves. There is probably more current available to the PCMCIA slots which is why the SRC doesn't have a problem.

Have you tried running the SR2 on B only? This may seem counter-intuative - but I have had better results keeping hotspots forced to 802.11b only. I'm using the SR2 card at most locations with great results.

I've tried the b-only, but I have a mix of SR2, SRC and CM9. Some like to work on g and give very poor speed on b .
meanwhile, we notice that quit a few clients (non-MT) have problems to get good speed when connecting to our sr2 while its works good if we have a cm9. We now start to use sr2 only for our backbones and use cm9 for the client connections.
For mt-mt connections, the sr2 works great. But unfortunately, the card don't like our clients...

UniKyrn, how do I do that? (reduce to 200 or 300mw)

You go into the properties for the wireless interface and set TX Power to something besides "default", which is max output normally. I believe 400mw is 26db, so try setting it to 22 or 23 and see if it becomes more stable. Also, be aware that you can't get 400mw out of that card when using 802.11g at max speed anyway. It will only produce that kind of output if limited to 11Mbit and lower speed, which means 802.11b, or 11g that has been rate limited.