We have been testing the 450i 900Mhz as a solution to a hard to reach area in a neighborhood. Originally connected 2 SM to the AP and they worked well enough to justify trying additional residences. Our 4th SM started off bad as we had a bad antenna on the first install attempt. Now the customer was connected and the SM dropped out in rain. The SM signal was at -73 before the storm rolled in. Anyone have any experience with the limit where these will start to drop off? I have seen others on here saying they can operate (roughly) at -88, ours would drop at -82.
Also there is an option to change the power level on the AP but not directly on the SM. Am i missing where this is located?
When you run an SA at the AP, what does the spectrum look like?
As far as changing the SM's power level, you'll want to leave this set at the default of 25dBm, and use the AP's SM Receive Target Level feature to automatically raise or lower the SM's TX power level based upon the target signal level. I'd suggest that you set this to -50dBm.
It really depends on the noise level. We've had stable connection in the mid -80s, and we've had SMs struggle to maintain session at -65.
At the end of the day, your link capacity and modulations being used are what matter. Everything else are metrics to try to help you boost capacity, and they can lie to you. In severe cases, I've had to align SMs using link capacity tests.
We've found with PMP450i 900MHz that we have to have an SnR of at least 8dBm in order for it to be stable and hold on. That being said, if there's intermittent interference spikes on the channel you're trying to use, it might cause a re-reg/drop. We've found that it sometimes takes a few days/weeks of monitoring SM's to find a channel you can use, and you'll typically drop down one channel size (e.g. 10MHz down to 7MHz) from what you thought you could use in order to keep a stable connection when there's a noise spike.