I don't think that is the case with MIMO radios, so you probably actually do gain some interference rejection then. I base this on Cambium's explanation of how ePMP is able to use dual slant sectors with dual linear client antennas by using phase to differentiate the two streams... of course I might be completely misunderstanding how all of this works.
On Wed, Mar 25, 2015 at 3:01 PM, Chuck McCown <[email protected]> wrote: > The only time where one a 0 is equivalent to two at –3 is if they are > phase coherent. Coming from the same source and phase locked with each > other. I honestly do not know if that is the case with the Mimo Radios. > > *From:* Mathew Howard <[email protected]> > *Sent:* Wednesday, March 25, 2015 1:58 PM > *To:* af <[email protected]> > *Subject:* Re: [AFMUG] AF5X polarization > > But in the case of dual chain radios, is what Ken said correct, that one > signal at 0db amounts to the same thing as two at -3db? If that's the case, > there wouldn't seem to be any interference rejection advantage to dual > slant over dual linear, regardless of what polarity the interference is. > > On Wed, Mar 25, 2015 at 2:55 PM, Chuck McCown <[email protected]> wrote: > >> Depends on which chuck you mean.... >> Slant helps with multipath. Linear to slant rejection is only 3 dB. If >> your interference is dual pol linear, you have two choices: >> Stay linear with a different frequency and hope for the best. Or use >> dual slant for a 3 dB reduction of the interfering signal. Better than a >> poke in the eye with a sharp stick. >> >> But if you are only running one single chain/radio and the interference >> is on the same frequency, orient your antenna 90 degrees to the >> interference and you will get 20+ dB of rejection. Irrespective of the >> absolute polarization. If they are +45 make yours –45 etc etc. >> >> *From:* Jeremy <[email protected]> >> *Sent:* Wednesday, March 25, 2015 1:47 PM >> *To:* [email protected] >> *Subject:* Re: [AFMUG] AF5X polarization >> >> Yeah, I knew about the multipath advantages. It seemed to me that 3db >> of rejection would increase your CINR by 3db. Am I wrong here? Chuck? >> >> On Wed, Mar 25, 2015 at 1:44 PM, Mathew Howard <[email protected]> >> wrote: >> >>> I'm not sure that it really gains much if anything as far as >>> interference rejection... I've read that even though the interfering V/H >>> signals are going to be 3db weaker, you're now going to be seeing two >>> signals (assuming dual polarity H/V interference) at that same signal level >>> and the two combined is essentially the same as seeing the extra 3db. >>> Hopefully someone who actually knows can confirm whether or not that's true. >>> >>> if that is the case, I think dual slant is mostly only going to help >>> with multipath issues. >>> >>> On Wed, Mar 25, 2015 at 2:36 PM, Jeremy <[email protected]> wrote: >>> >>>> Well if I can gain 3db by turning 45/45 I'm all over that. >>>> >>>> On Wed, Mar 25, 2015 at 1:32 PM, Josh Luthman < >>>> [email protected]> wrote: >>>> >>>>> That's what everyone keeps saying =) >>>>> >>>>> >>>>> Josh Luthman >>>>> Office: 937-552-2340 >>>>> Direct: 937-552-2343 >>>>> 1100 Wayne St >>>>> Suite 1337 >>>>> Troy, OH 45373 >>>>> >>>>> On Wed, Mar 25, 2015 at 3:30 PM, Jeremy <[email protected]> >>>>> wrote: >>>>> >>>>>> 3db right? >>>>>> >>>>>> On Wed, Mar 25, 2015 at 12:54 PM, Josh Luthman < >>>>>> [email protected]> wrote: >>>>>> >>>>>>> Rejection from other V/H radios. >>>>>>> >>>>>>> >>>>>>> Josh Luthman >>>>>>> Office: 937-552-2340 >>>>>>> Direct: 937-552-2343 >>>>>>> 1100 Wayne St >>>>>>> Suite 1337 >>>>>>> Troy, OH 45373 >>>>>>> >>>>>>> On Wed, Mar 25, 2015 at 2:53 PM, Ken Hohhof <[email protected]> wrote: >>>>>>> >>>>>>>> Anybody know what you give up by using V/H instead of dual slant >>>>>>>> with the AF5X? >>>>>>>> >>>>>>>> If the path has clear LOS and no multipath, I can't see why it >>>>>>>> would care or even be able to tell the difference. >>>>>>>> >>>>>>>> >>>>>>> >>>>>> >>>>> >>>>> >>>> >>>> >>> >>> >> >> > >
