Am I blind, or is there no Cambium ePMP 2.4Ghz sector antenna radiation plots available? I know Mars Antennas makes them and I have the part number (MA-WD24-DS14CM), but I can find nothing on their site, here at Cambium, or anywhere on the web as far as radiation pattern goes. The closest antennas I can find radiation patterns at the Mars site is MA-WD24-15 and MA-WD24-DS15.
I am most interested in the F/B ratio pattern. For our first tower we went with the KPPA-2GHZDP90S-45-WC. While they have great gain, and find their pattern plots to be true (right down to the F/B ratios), I am not completely happy with things.
We are using ABAB with 20Mhz channels (6 and 11) in a rural enviroment. As our customer base grows on this tower and sectors begin to crank out more data, I am finding some customers with very strong DL signals and absolutely no interference in their immediate surroundings (have ran eDetect and spec-an) are dropping from MCS15 to MCS13. I have noticed a correlation between this MCS reduction and their signal level from the opposite sector (gathered from the Monitor -> Wireless tab and eDetect scans). This reduction also happens when opposite sector is very active. I can run a wireless link test at 2am from these SM's while watching the MCS values and they hold at a MCS15. Run wireless link tests at 8pm when opposite AP is pumping data and these SM's fluctuate between MCS14 to MCS12 with MCS13 being the most constant hang out spot.
Here is an example. SM1 is about 35 degress from boresite of West AP, which it subscribes to. eAlign shows -48dbm with about 3db difference between chains. It also sees the East AP at -70. This gives a CINR of 22. When looking at the RF Planning chart of the ePMP ABAB Frequency Reuse Deployment guide, due to the 22db CINR this SM should be holding between MCS13-12 (even though it has a -48dbm RSSI) , which it does. Also, looking at the KP antenna radiation pattern, I should have about a 22db F/B ratio at a 35 degree offset from looking directly down the bore of the antenna.
It all lines up and boils down to self interference due to low F/B of the AP antennas for SM offsets greater than 25 degrees of boresigh to the AP. I downloaded the MA-WD24-15 and MA-WD24-DS15 antenna patterns. The 15's F/B looks very similar to the KP's. The DS15 shows superior performance to both the KP and the 15 in the F/B arena. At a 35 degree offset from boresight, it shows a greater than 30db of F/B. This would eliminate the self interference issue we are seeing to our SM's. I can live with a 2db drop in gain for a close to 10db gain in F/B at boresight offsets greater than 20 - 25 degrees.
I am asking for these antenna plots as we are about to light up 2 new towers and if the Cambium sector has noticeably better F/B than the KP's we will be haning Cambium sectors this go around. I could not find such plots for our first tower and went with the KP's as the KP sales rep guaranteed the KP sectors was better in all aspects over the Cambium sector. I figured he must be right since KP had readily available antenna pattern plots and Cambium did not.
And before anyone jumps on the 'increase your downtilt' bandwagon. That is not the problem. We carefully calculated our downtilt with the electrical downtilt of the sectors factored in. We built or our own tower and it is plumb. We also used levels with offset degrees to set sectors downtilt. We can not have too steep of a downtilt due to the 80-90' pine trees that plague our entire area. We are having to mount some SM's in the top of these trees (Newkirk knows what I mean) so that we do not have a -80dbm at 3/4 mile away from tower. It is the F/B of the KP's causing our issue and only an antenna with better F/B at a large azimuth degree range will help our issue.
I do not want to call anyone out, but I know a few of you have extensive experience with both the Cambium and KP 2.4Ghz sectors. Would love to hear any input you would like to give. Same for any Cambium employee. And if anyone has the radiation pattern plots (which most likely have been right in my face and I have overlooked them) I would love to have a copy.