Hi all was looking at the data sheet for the 4525 SMs and I see -56dbm needed for DS11… setup link planner and a 4525 SM 6km away, full line of sight, -56 dbm and is only sitting at DS7 99.998% availability. Am I doing something wrong?
Just using LinkPlanner, nothing deployed yet. Unless I am not seeing whats available on LP lol
Ooops, my bad, sorry about that… what region are you using? What channel width? I assume you’re modeling using ePTP mode? You’re using the 5.8 band?
When I model this in both US/FCC and Canada for 5.8GHz using ePTP mode and 20MHz @ 6km/3.7mi LOS, I get the expected results:
hmm okay, I was trying a 40mhz channel but as per datasheet it says DS11 is attainable at -56dbm. I will try a 20mhz channel
So now I’m getting confused… the data sheet actually says:
Nominal Receive
Sensitivity (w/FEC) @40
MHz Channel
MCS 0 = -88 dBm to MCS 11
(1024 QAM-5/6) = -56 dBm (per chain)
Keyword being “per chain”… so I think that this means that the combined stream needs to be -53? in order to achieve MCS11… but when I model this in LinkPlanner online, MCS11 is only achievable at around 14% of the time, followed by MCS10 at 29%:
So yeah, I don’t know why there is this disparity between the data sheet and LP online, although I’ll generally trust LP over the datasheet for modeling.
Ya that’s strange… but good to know and I agree, follow LP. Thank you for your input.
Something youll find as well during a live deploymemt is that there is quite a large disparity between what LP stated your signal should be, what experience says your signal should be, and what you actually receive. It seems like the RSSI is several points lower than what it should be. With that said, the latest release has beamforming and if i understand correctly the gains dont show up im the gui for RSSI. Another thing to rememeber is that the GUI may show a lower than expected MCS level. However, if beamforming is enabled, the MCS level will go up when traffic is traversing the link. Its almost like the SM goes to “sleep” in a way, probably a side affect of the beamforming not aorrying about targeting that SM since there isnt any traffic on the link.
I can tell you first hand, you can achieve a MCS11 at less than a -53. Mid to upper 60’s alot of times will get you a MCS11 or higher. Its surprisingly more obtainable than you might think.
1 Like