I have 2 SR9’s that are suppose to be on ch 6 via wds, the thing is, Tower 2 SR9 wont communicate via WDS to CPE on ch 5 like they are suppose to, I have to leave CPE on ch 6 and put tower 2 SR9 on ch 7 then they connect via wds.. WTF ch 7 is not even supported on the SR9. I have rebooted both cards, disabled, enabled everything I could think of.. They are on 5 mhz. BUT !! If I put them on 10 mhz, they both connect fine on ch 6. Seems to be an issue with the SR9 radio on tower 2.. BUG? Defect? Recap. 5 mhz connect via wds only with tower on ch 7 and CPE on ch 6. 10 mhz all is fine. Problem is that I HAVE to be on 5 mhz as connection is not strong enough for 10mhz or 20mhz.
ANy input? MIKE???
Becuase of the limited size of the non-licensed 900 MHz spectrum (902-928 MHz), you don’t have alot of room to move, as a result the smaller the channel size the higher the potential for ‘harmful’ interference. I have had the same problem at a site I use 900MHz, periodically when using 5MHz channels you can see massive amounts of interference enough that it causes disconnects. When the interference dissapears my link is fine (-59 rx, -62 tx), when its present (-83 rx, -87 tx) and the link goes in and out. If I remain on 5MHz channel sizes and just change the channel it will work fine, if I switch to 10 MHz or 20 MHz it will also work fine. I have been able to repeat this in a lab setup with an old 900 MHz cordless phone. The phone when activated will pick a channel to operate at, if it doesn’t overlap with the SR9 setting everything is fine, if it does (happens about 10% of the time), then I get huge issues with interference.
I am not saying it can’t to something else, but sounds like interference to me. Look at http://www.ubnt.com/downloads/SR9_Mtik_PtP.pdf it is a study by Ubiquiti using RouterOS and SR9, pay particular attention to the ping times. In all their cases there is a periodic spike in ping (this is what occured to me when the 900 MHz phone started to operate at the same frequency as the SR9). Not only can in band interfernce has this affect, but strong out of band interference can do this too, thats why Ubiquiti designed a cavity filter for the SR9 (http://www.ubnt.com/cf.php4).
As for the channel 7 thing, the SR9 is not a true 900 MHz radio, it downsamples/upsamples to a (2.4Ghz?) radio. Hence the resason you can get some functionality at those settings. All my tests at trying to run the SR9 out of the designed frequency space have not been very sucessful, typcially can get it to connect but performance is very poor.
As a side note, the SR9 doesn’t seem to need alot of signal to maintain decent speeds. At a stable (no interference) -80 tx/rx I’ve been able to achieve over 9 Mbps TCP thoughput. Also if your having signal issues my recommendation is to lock the radio air rates at a MAX of 24 Mbps, this makes sure the radio is always operating at max tx power, and still maintains resonable rx sensitivity.
Reply appreciated, but my issue is that I have 2 sr9’s that can ONLY communicate when one is on ch 7 and the other on ch 6, with both on ch 6 , they dont link up