Question regarding the pmp450m, in the sounding statistics tab of the AP we can see the various spatial frequencies and azimuth (degrees) listed...
But what i find odd is the degrees are listed with multiple numbers sometimes 2-3 numbers one always negative and 2 positives...
What do these numbers represent in relation to actual azimuth in relation to the antennas alignment?
The reason I ask is I've coded some internal scripts to take the airdelay and validate sm latitude/longitudes, to confirm drastically incorrect latitude longitudes from installers with much success...
Is it possible to turn the tracking azimuth from a 450m entry into an actual azimuth/bearing from the antenna direction of the 450m?
The azimuth values displayed are derived from the spatial frequency. However, due to the repetitive nature of the spatial frequency, it is impossible to resolve this to a single azimuth. So we display a list of possible azimuth values. Let us consider an example. First, note that bore sight is at 0 degrees azimuth. Now say an SM resolves to a spatial frequency of 379. For the 5.4Ghz band, we can derive that this means the SM could be at an azimuth of -37.2, or at an azimuth of 17.6. We don't know which one is correct, but it is one of those. So again, the azimuth values displayed are a list of possible values, but only 1 is the actual azimuth for that SM. Hope that helps. Feel free to follow up with any questions.
Ahh yes I forgot about that, sorta puts a Cabash on my idea then, how come some appear to have 3?
Hello, to expand on what Anthony is saying, when a beam is created to the intended SM, additional beams are created about 50 degrees off of the original azimuth (by nature of how the RF elements are energized). A zero azimuth is dead center, so you will see three angles for the first 5-6 spatial frequencies (-50, 0 and +50 degrees). Once you get past ~7 degrees, the third beam goes outside of the range of the antenna and only two beams come into play. From the AP's perspective, if the SMs are within either of those beams, the AP considers them as one (multiple TDD cycles would be needed to service them).
These values are SNMP pollable, so you may be able to take this information and overlay it on Google Earth to get an idea of where you can add users to AP and actually increase the overall sector performance (or where you don't want to focus anymore). The simple end goal for an operator would be to evenly distribute your customers across all of the spatial frequencies (versus clump them all into a few). That will give you the maximum spatial multiplexing gain (average number of beams per TDD cycle).