It is completely different. FDD systems rely on frequency separation not time to mitigate interference. If a TDD system transmits and receives the same frequency from a given site, it (and possibly adjacent channels to it) cannot be re-used from that site by another FDD system. With FDD systems, frequency re-use is generally a function of difference in path azimuth and antenna performance. As long as the high/low plan is maintained, all interference cases will be limited to the far-end site where there’s at least some free space loss and antenna discrimination to reduce the interfering signal. When TDD is introduced as proposed here (transmitting and receiving the same frequency at each site), the interference potential is co-located. Let’s not forget that 99.99999% of everything licensed and installed today is FDD.
From: Af [mailto:af-boun...@afmug.com] On Behalf Of Mike Hammett Sent: Tuesday, October 20, 2015 7:57 AM To: af@afmug.com Subject: Re: [AFMUG] Mimosa B11: Exactly what does the mounting look like? Agreed. I don't see how it's any different. You license any channel + polarity + direction you would Tx on and the standard interference checks have you taken care of. ----- Mike Hammett Intelligent Computing Solutions http://www.ics-il.com ________________________________ From: "Faisal Imtiaz" <fai...@snappytelecom.net<mailto:fai...@snappytelecom.net>> To: af@afmug.com<mailto:af@afmug.com> Sent: Tuesday, October 20, 2015 6:06:48 AM Subject: Re: [AFMUG] Mimosa B11: Exactly what does the mounting look like? >>>Instead, the challenge is in assessing and accepting the risk of possibly >>>bucking your own 11GHz links or other operator's 11GHz links on or near your >>>two endpoints. As there is no reliable way to calculate this type of >>>interference, you may only become aware of the problem after you have >>>installed and turned up your TDMA system. Call me stupid, and please explain how that is ......I can understand the issue of channel/polarity availability...however how is this potential interference different from current ..... Today, one cannot use the same channel/polarity on the same site anyway... The B11, actually opens up the possibility of channel reuse, on the same site with angular separtion ...(possibility being a key word). Regards Faisal Imtiaz Snappy Internet & Telecom 7266 SW 48 Street Miami, FL 33155 Tel: 305 663 5518 x 232 Help-desk: (305)663-5518 Option 2 or Email: supp...@snappytelecom.net<mailto:supp...@snappytelecom.net> ________________________________ From: "Mike Black" <mbl...@bamicrowave.com<mailto:mbl...@bamicrowave.com>> To: af@afmug.com<mailto:af@afmug.com> Sent: Tuesday, October 20, 2015 12:45:25 AM Subject: Re: [AFMUG] Mimosa B11: Exactly what does the mounting look like? +1 to Tim's remarks in this thread. The challenge isn't in coordinating the same frequency pair in H and V between two sites, in both directions. Instead, the challenge is in assessing and accepting the risk of possibly bucking your own 11GHz links or other operator's 11GHz links on or near your two endpoints. As there is no reliable way to calculate this type of interference, you may only become aware of the problem after you have installed and turned up your TDMA system. If there are no other 11GHz systems within about a half km of either site and you don't plan to expand either site with additional 11GHz equipment from other vendors, you may be ok. If not, then ? Mike Black Black & Associates 727-773-9016 www.bamicrowave.com<http://www.bamicrowave.com> [logo.png] black & associates Frequency Coordination ● FCC Licensing ● Engineering Design -----Original Message----- From: Af [mailto:af-boun...@afmug.com] On Behalf Of Hardy, Tim Sent: Monday, October 19, 2015 8:29 PM To: af@afmug.com<mailto:af@afmug.com> Subject: Re: [AFMUG] Mimosa B11: Exactly what does the mounting look like? In the olden golden days building the MCI route with full block systems, we would have "bucks" or "bumps" in frequency plans when required, and we learned first hand how important it was to use ultra high performance antennas or better in such situations. With very little free space loss, antenna performance is key and there is very little reliable data on close-coupling antenna performance, so it is extremely difficult to accurately calculate expected interference levels in these situations. With the prevalence of 2&3' antennas these days, antenna isolation will be an even larger challenge. Sent from my iPhone > On Oct 19, 2015, at 8:03 PM, Seth Mattinen > <se...@rollernet.us<mailto:se...@rollernet.us>> wrote: > >> On 10/19/15 16:56, George Skorup wrote: >> To make Tim's point, we're co-located on a couple towers with other >> 11GHz users and using both the high and low of a channel pair at both >> ends is unpossible. (yes, that's a word :) > > It's a perfectly cromulent word. > > ~Seth
