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Fran66
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Looking for reliability, SR2 or CM9???

Thu Dec 01, 2005 5:23 pm

Hi, I need your experiences, I am setting 2 RB532 AP's 2.9.8 with omnis on a roof of a 60 floor building, with the sr2 I have run into B/G mode problems with prism2.5 clients and wraps 2.8.26, should I only set G mode only on the ap and change clients cards for cm9? or change AP card for a cm9 and stay B/G on the AP.??

My goals are "stability", low latency, bandwith is not important ( i need only 1 Mbps or less to the clients)
 
MyThoughts
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Thu Dec 01, 2005 7:20 pm

We are currently using RB532 as both AP's and CPE, with both CM9 and SR2 cars. As far as stability is concerned we have had no issues with stability with either of the cards. However, we have had 3 CM9's fail after about a month in the field (3 of ~20), the cards didn't fail completely though, on 2 of the cards the recieve sensitivity went (ie. even when 20 ft away signal strength was -90 db), on the last one the radio transmit went (ie. strong receive signal, but tx power was a problem). The cards were replaced and everything is working fine. We have just started using the SR2 cards ~ one month ago, but so far no issues at all.
 
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djape
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Fri Dec 02, 2005 12:27 pm

Ok, here is my advice:

SR2 are having issues with noise/latency and CM9 have issues with permanently loosing strength when ever bad wheather is out (I have expirienced this only on omni antennas).
Also SR2 will work on PC installation but on RB532 you'll have issues with power supply cause SR2 is spending more power than CM9.
Also, SR2 is ok if you don't have plenty other 2.4ghz AP's arround.
My advice is to use CM9 with lightning (surge) arrestor.
Mixed B/G mode is not a good idea but rather G-only.
Clients should also use CM9 or any other Atheros b/g card.
Set short preamble to all clients and AP's and that's it :)

Cheers...
 
sten
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Sat Dec 03, 2005 2:31 am

SR2 are having issues with noise/latency and CM9 have issues with permanently loosing strength when ever bad wheather is out (I have expirienced this only on omni antennas).
Never had any issues like that with CM9's, but i have experienced that with all radios that have been too close to a soldering iron or heating gun.
 
Fran66
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Sat Dec 03, 2005 5:31 am

On that tower I detect 48 APs on 2.4 Ghz, I have set the cm9 and the SR2 on the AP on B only or G only without problems, the problem is when I use B/G ond the SR2, with cm9 and prism clients, the ones with cm9 register but the ones with prism not. So.. I am asking if you people set APs on G or B only looking for stability, or is an issue with that card?? I have set the CM9 on B/G without problems.. so what is different aren't they from the same atheros chip?
 
sten
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Sat Dec 03, 2005 6:00 am

wouldn't want my worst enemy try mikrotik's implementation of mixed-mode b/g on routeros. :twisted:
Mind you, i haven't tried that mode on v2.9.8.
 
yogi
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Wed Dec 07, 2005 7:26 pm

Lots of interference around, with stability and latency as the objective, and not bandwidth. So run B on a CM9.

Changing the prism chipset on the clients would be nice, but only if you can reuse the cards somewhere else.

The CM9's do fail eventually if run hard, long and not ventilated properely. With proper cooling there is no problem.
 
tully
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Wed Dec 07, 2005 9:42 pm

 
jdmarti1
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Thu Dec 08, 2005 3:06 am

I have the SR2 and SR5 cards, as long as you correctly set the power levels to work around what MT does, the SR cards are awesome. Latency is not a problem at all - only when the cards are overdriven. These cards are definitely the shiznit for WISPs - We have had them in service since July in Oklahoma, and had no problems. At least until I set the Tx power to default and ran into the problem of overdriving the cards. As soon as I lowered the power back down, all was good. I would recommend them to anybody. (Except my competitors!)
 
yogi
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Thu Dec 08, 2005 10:05 am

shiznit
:lol:

If you lower the power output, what benefit are you getting out of the SR2 opposed to the CM9? The CM9 has the same chipset but the SR2 is enhanced by UBNT. At a 3/1 price ratio what are you getting for your money?

You can tell us your opposition wont read this post!!!
 
tully
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Thu Dec 08, 2005 10:11 am

Please re-read the link above!
 
yogi
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Thu Dec 08, 2005 11:16 am

Please re-read the link above!
Sorry, read it before the last 2 posts which explains it nicely.

Still would like to see some opinions on whether they are worth the price as power does not necessarily equate to performance.
 
jdmarti1
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SR Cards

Thu Dec 08, 2005 7:02 pm

You might want to look at the specs a little better. Pwr is not the only enhancement. I do like the power, because using an omni antenna, by the time I add in cable losses, I am at FCC maximum with a 13dBi antenna. Tell me how you can do that with a CM9 card? Then take a look at the Rx thresholds. We have setup some test links that were very near the thresholds. We couldn't make the link with other AP's - the SR cards were clickin' right along. That alone makes the card worth the money to me. These cards are awesome - and now that we know to not set MT to default, but instead just set the output at 26, there should be less problems.