Hi Paul, I am assuming this is an ABCABC GPS sync site you are talking about.
Please make sure to check the front to back ratio of the antenna you choose to use. We, Cambium, recommend 30-35 dB. A front to back of 30-35 dB makes sure that the back side AP is heard less than 30 dB than the intended AP in the DL for an SM. MCS 15 requires around 28 dB CINR. If for example the front to back is 23-28 dB, then when the back side AP transmits at the same time the receiving SM will have increased noise from this back side AP and cannot hear at MCS 15 from the intended AP. The same thing will apply to the UL. The AP will be listening to an SM, but a back side SM will transmit at the same time. If the front to back is 23-28 dB, then you will hear the back side SM and CINR will be decreased less than 28 dB and MCS 15 will not work. This will cause rate adapt to decrease your MCS and your throughput to decrease. So you can get higher gain antennas, but if their front to back is not 30-35 dB, they will actually perform worse than a lower gain antenna. The dual slant comments also apply to 5 GHz. Dan Sullivan ePMP Software Manager From: Af [mailto:[email protected]] On Behalf Of Paul McCall Sent: Friday, December 04, 2015 1:00 PM To: [email protected] Subject: [AFMUG] to slant, or not to slant - that is the question We are looking at smaller sector sizes for a 5 Ghz ePMP cluster (60 degree probably), and am considering my options, which might also increase my gain quite a bit. Using a non-Dual Slant sector such as AM-5AC21-60, would increase my options. There have been a calling threads on Cambium's sites about whether Dual Slant was a big factor at the AP if the SMs aren't dual-slant. Cambium's Daniel Sullivan made this comment ... The thread was originally about 2.4 Ghz options, so not sure if it applies exactly to 5 Ghz. Paul
