Would it be a problem to have same frequency of 906MHz on all 3 APC’s with 11.5dBi 120sector horizontal polorized antenna? We seem to have too much problem with other frequencies.
Usually not a problem. You may want different color codes and proper sector IDs to keep the SMs from jumping around. However I have seen some 3X120 setups work great on the same Color code as well.
Set it up and tweak it to what works best for your location.
I’ve always assumed that that would not work.
cmosher: Do you have radios in this configuration working? We’re wondering what is the best way to go, as we’ve got about 100 SMs on our primary AP, also on 906. We can’t run three 120’s on the three different frequencies, because 924 is full of garbage on the order of -65dB in every direction here.
Anyway, I’d love to hear anyone else who has this running, or has tried and failed. What kind of antennas did you use, what kind of physical separation, etc.
I am currently running 3 900APC on 120 degree 13.5db sector antenna and have on many occasion gone to the same FQ . I have found that the AP to SM association (no SM jumps from one AP to another) is stronger with non-overlapping FQs with different color codes and designated sector IDs… I always have the three non-overlapping FQs (906-915-924) selected on the SM in the event that a FQ change is needed. (noise floors change constantly here) I manage this POP in relation to three other POPs in the same area (all Mine) and manage the sector ID Color Codes, FQs and AP settings (distance, power level, 2X, etc.) the same on all of them to maximize the GPS sync on all POPs. I am using a combination of Sync carriers… CMM, Sync Pipe from PacketFlux, and transferring sync from adjoining POPs and have found that all work in unison as long as they are mirrored in regards to the settings. FQs are irrelevant (other than availability) however, I have made it a “habit” to daisy chain the FQ usage utilizing the three non-overlapping FQs even in regards to the adjoining POPs.
Can you use the same FQ on all three in you 120 degree cluster… yes… just make sure the Color Codes and sector IDs are managed properly…
I hope this helps… It works great here in our little chunk of TX and NM and we are a border city with MX that doesn’t regulate FQ usage… it IS a challenge!
P.S. There is some great reading on cluster management in the Users Guide… I suggest reading it… it is very enlightening.
Same freq. on all APs? would this be possible in a 5.7 cluster? I always thougth that if they are in sync why would you need to use different freq? Why does motorola insists on using non-overlapping channels?
Guys… read the manual on cluster management… particularly “Engineering your RF Communications”, it will provide priceless info on all these questions…
http://motorola.canopywireless.com/supp … on=1&cat=8
It will explain the reasons for the established guidelines and help you better understand the need for a proper sync provider and color codes, sectors, and non-overlapping FQs… (yes, it can also covers 2.4, 5.7,5.4, etc.)
Make these guidelines a standard and then you can tweak according to your particular situation.
The issue I see with using the same freq on all channels is that you will get some inter-modulation between AP’s. SM’s that are not 0 degrees on axis with an AP may have some problems.
With that said, in a high RF noise environment one has to make adjustments. If you have two of the non-overlapping channels available, then try to use both. In some cases only one channel is available, but going to one frequency should be a last ditch effort.
Keep in mind that your environment is not static. It will change at some point down the road. Betting the entire customer base on one frequency is a little too risky for me. In my mind it would be better to use three channels and work with higher gain SM side antennas to try and compensate.
Putting the same frequency on all APs is a very, very bad idea.
Most of your customers can probably see two or all three APs. If the hear two APs at similar signal levels, which is VERY common, then they won’t hear either very well and you will get error rates through the roof.
cmoshier who says “Usually not a problem” is dead wrong, and if he actually follows his own advice, then he also has a very broken network
If you have three horizontally polarized antennas and you can’t find one unique frequency that works on each of them (use the spectrum analyzer feature) then you’re fu*ked.
No two contiguous APs should be on the same frequency or on overlapping frequencies. This will ruin your one usable frequency.
If 915 and 924 are hosed across all three antennas, then you are probably very close to the noise source. In that case, you picked the wrong frequencies to run at.