Prizm reported RF Link Dist ...???

Prizm3 consistently reports a much smaller RF Link Distance than what the SM reports (via web gui to sm). I have looked at having Prizm display:

RF Link Distance Mi
RF Link Distance Km

RF Link Avg. Distance Mi (reported on AP only, avg dist of all SMs)
RF Link Avg. Distance Km (same as above)

I want to use this information to help me RF Power balance the SMs in each of our 900 sectors.

Can someone shed some light on these figures from Prizm…??

Any and all help/information is greatly appreciated…!!

This is a known bug in Prizm. Been there at least since the 2.x days.

From the Prizm 3.0 release notes.

Prizm Reporting Incorrect Distance for 900-MHz SM
For only the 900-MHz modules, the following distance amounts are exactly half of the
correct value:
◦ Distance shown in the Details pane for the SM
◦ Max Distance and Average Distance shown in the Details pane for the AP
◦ distances shown in the following columns:
− RF Link Distance Km
− RF Link Distance Mi
− RF Link Avg. Distance Km
− RF Link Avg. Distance Mi
Until this problem is resolved, Canopy will continue to track it under Item ID 0004108.
Prizm reports correct distances for all other SMs.


The dB level of each SM as reported by the AP in the sessions page would be a better value to use for RF level balancing.

Take your noise floor, add +10dB then adjust each SM to fall within a 10dB range.

Noise floor = -82dB
SM Low Range = -72dB
SM High Range = -62dB
SM Target = -67dB

Of course there will be some SM’s that will not even be able to get into the low end of the spectrum, however this is a good rule of thumb. For your weaker links, you can decide to upgrade or raise the antenna if needed.

Thanks for the replys folks. I guess I glossed right over that portion of the release notes.

moto give any idea as to when this issue will be fixed…???

Kind Regards,