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question about signal strength and ccq

Posted: Fri Aug 12, 2011 10:48 pm
by gcs
Why does the signal strength not seem to have no relationship with ccq? I have several customers connected in the 60 to high 70's with ccq in the teens and 20's and some on the same tower with sig strength in the 80's and ccq in the 70's. All are using RB 411 on client and RB 433AH on tower. All are 4.17 ROS and using R52 radio cards.

All customers using 15db are line of site less than 1 mile. We are using 2.4ghz. This tower also has 5 ghz backhaul and 900 on the same RB433AH. The 2.4 antenna is a 15db omni. The 5ghz is a 3' dish pointing away from the 2.4 clients and the 900 is a 8db omni.

Thanks for your help.

Re: question about signal strength and ccq

Posted: Sat Aug 13, 2011 7:18 am
by mramos
Hi ...

Which frequencies are you using on 2.4 & 900?

If 900 is a XR9/SR9, the IF is at 2.4G (2442, 2437, 2432, 2427) and sometimes creates interference on 2.4.

Regards;

Re: question about signal strength and ccq

Posted: Sat Aug 13, 2011 10:20 am
by wirelesswaves
The CCQ will start to elevate once the CPE starts transfering moderate amounts of data.

Try pinging the CPEs in question from your desktop or from the AP, and then monitor the CCQ again.

Simon

Re: question about signal strength and ccq

Posted: Tue Aug 16, 2011 6:59 pm
by gcs
Thanks for the info. when I ping some of the clients the ccq does go up higher. What is a level that should be the minimum and still have good Internet connection?

Re: question about signal strength and ccq

Posted: Tue Aug 16, 2011 11:47 pm
by WirelessRudy
Thanks for the info. when I ping some of the clients the ccq does go up higher. What is a level that should be the minimum and still have good Internet connection?
The higher the better in general. 100% is what your should try to achieve. But it also depends on what kind of quality you want to serve your clients.
Gaming really needs a ccq of close to, or 100% (with low latency) and Voip (+ Skype) at least above 90% and browsing and streaming videp/radio can do with at least 70 to 80%. Downloads can do with much less. It only takes longer to download something. (And the overall AP-CPE network gets occupied due this much more.)
Low ccq's means lots of digital packages get lost during transport. They have to be resend which delays the total usable data througput. For ´real time´ traffic it is a definite killer.

And like others already mentioned, the ccq should scale up when traffic is on the link. But the link also needs to be able to sustain high ccq at the higher data rates. If not AP starts to step up and down the data rates which comes with small disruption of the data flow and also creates more overhead. In general the data throughput suffers.
If you find you ccq's never reach the high value try to set the AP's data rates lower. Disable 54M, 48M or even lower values until you see good ccq's. Run a ´flood ping´ to ´test´ the links for the best settings.

Now, in an ideal world your network would also be in an open environment without bounced and disturbed signals and no other's using same band. A ´clean´ spectrum.
In real world this is not the case. Now you will find that although some client seem to have good signal strength their ccq stays low. Interference or multipath receipt can be an issue here. And both of these can differ per client.
So to find out if you client suffers from other signals runs a wireless scan at his antenna.
If you also want to find out about multipath receipt interferences or other disturbing signals (high power radio stations, elec. transformers, high voltage line, microwaves, cordless phone etc.) than you need a spectrum scanner.

Hope this helps...

Re: question about signal strength and ccq

Posted: Wed Aug 17, 2011 2:15 am
by gcs
That was very helpful. Thank you for your help.