The support engineers will be able to quick check things like frequency planning and synchronization settings between the 450i and the PMP 100, frame utilization, RF discards, spectrum analysis etc. and try to narrow down the problem.
On the Radio tab, in the Power Control section, change the field for SM Receive Target Level.
We had almost the exact opposite experience at two small subdivisions. I kept turing up the SM TX powers, to overcome what I thought was interference, and things got worse - I could keep all but one or two SMs registered reliably. Changing the frequency would cause a different SM to drop. I ended up lowering the AP (20 dBm) and SM TX powers (receive target of -65 dBm) and things have been stable and amazing for a month now. Couldn't be happier.
I think (and this is only an educated guess on my part) that various situations involving Non-LOS conditions really affect the signal propagation differently, and that different Tx Powers will be necessary to maintain a stable, optimized link.
Thanks for sharing this information with the community.
I totally agree. In our situations, for those small locations, there was just way too much RF bouncing around. Lowering the TX powers made a huge difference in reliability. We even ended up removing some of the directors of the yagis (handheld bandsaw to shorten the full length) for the super close SM's.
We are still have throughtput issues, on our new 900 equipment. Up and down, one minute i can pull 20mbs down then 2m down. What are you guys running your 900 equipment in to achieve the throughtput i see on the forums, Which channel and freq are most of you using and the average sm power and AP power.
The default value of target SM power is -52 and that seems about right for a fairly high interference environment. If you don't have a lot of interference, and you have both near and distant subs, and are re-using frequencies back-to-back, then you might lower it to keep near SMs from interfering with the opposite sector through the back of the AP antenna.
The best channel to operate on will depend on your environment, no one else can tell you. Be sure to do an SA from both the AP and SM side to see where the interference is. If other operators are using Cambium 900, try to match timing parameters with them, if you can't go on a different frequency.
If you are mixing this with 900 FSK, be sure to use the frame calculator, also pay attention to the legacy framing mode setting.
I also highly recommend graphing at a minimum the signal level and SNR on each SM, to see if they are varying and causing the throughput to vary. If you have NLOS, many strange things will happen in 900 MHz with reflections, multipath, trees leafing out or leaves getting wet, etc. This can change your signal as well as interfering signals.
If you are in a farming area, they might be firing up RTK systems on 900 MHz as they prepare to till the fields, apply fertilizer, and plant.
