What is everyone using as a baseline for the minimum RSSI on their 2.4 gear? This is the first time we utilize Cambium gear as well as the first time we use 2.4Ghz equipment. I'm trying to figure out what we should deem the minimum RSSI on customer installs with this equipment. It does seem like it has a lower receive sensitivity compared to UBNT gear, but I do not want to install anything that could cause the SM or AP any issues. I want to keep a solid network, but also want to pick up as many new customers as possible all the while being confident that the equipment will not cause too many problems. I was thinking -75/-78, but I did see good throughput at -82. Would this be pushing it?
It's going to depend on the noise floor where you are deploying and what you consider acceptable MCS levels at the AP and CPE. If you are deploying 2.4 in an urban environment to deal with foliage you may need a -50 at the CPE to get above the noise. In a really rural setting -75 might be just fine.
In the few rural settings that we run 2.4 we still often see a noise floor of about -75~80 so -65 is about as low as I like to go, but do see good results sometimes with -70~75.
Well, our target is -60 ideally. We figure that should work really well, even in the face of some interference. We're also finding that -70 seems to work quite well also, BUT we know the math means that the AP will have less capacity with everyone being a -70 instead of everyone being a -60.
We do have a few clients who are mid to high 70's due to distance or trees, and of course that's not a good idea if you can avoid it. Those clients struggle more on the upload than they do on their download. The noise at a distant rural client might be relatively little, other than their own router and their own phone or baby monitor - so on the SM side if the signal is a -76, the noise may be controllable. On the AP side, if you have non-controllable noise from a competitor or non-syncable gear, then that -76 on the AP side might be difficult for the AP to hear much.
That all being said - we have been blown away at how well the ePMP works in the face of noise. Cambium is amazing! But it's also not going to be magic. If you have all your clients at a -77, then the whole capacity and potential and performance and scaleability will struggle compared to having everyone at a -57.
I'm trying to keep the SNR at or around the mid 20s at a minimum. As far as the MCS rates, how do you judge the minimum rate to install a customer at? MCS9? MCS10?
we don't have a mininum RSSI, we use a minimum MCS % rate.
for downlink we want a minimum of 50% of the data be moved at MCS 13. and 50% of uplink moved at 12. sometimes we will bend on that rule if the AP is low on population
winter time, we add a minimum RSSI of 60db (without reflectors) durring new connections. durring the summer, just code state rule.
those extra winter restrictions leave us about 15db to fade, and another 8db gain to add with a dish if needed.