Thanks for the detailed explanation, it is very helpful in understanding the concerns.
:) 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 > From: "Daniel White" <afmu...@gmail.com> > To: af@afmug.com > Sent: Tuesday, October 20, 2015 11:08:25 AM > Subject: Re: [AFMUG] Mimosa B11: Exactly what does the mounting look like? > Typically sites are licensed as “low” or “high” to prevent bucking… meaning > all > radios in a frequency band at that site will be either low or high. This > increases frequency reuse. > Mimosa TDD radio requires a TX high and TX low at both sites. This inhibits > traditional FDD licensing scheme to minimize interference and creates the > possibility of bucking. > Bucking definition from a Commscope newsletter: > “…High/Low conflicts or “bucking” situations. A “bucked” site is one in which > the transmit and receive frequencies at or near a site are on the same side of > an FCC frequency plan. This means that the required frequency separation at > the > site is being compromised. This is a very undesirable situation because at a > minimum, it can limit future frequency expansion around the site. At worst, > harmful system interference can occur to one or more party's paths.” > Frequency reuse, with traditional FDD radios, is very possible at a site > depending on TX power, antennas, and azimuths (vertical separation can play as > well). I’ve designed a number of systems in this fashion. Mimosa GPS sync of > course only helps with other Mimosa systems (unless other manufacturers design > a TDD system). > Obviously any of the frequency coordinators can explain this better than I… > but > I think something is being lost in translation. Also to Gino’s point, the > Mimosa radio requires 320MHz of TX spectrum per site, where the Ceragon IP-20C > would require 160MHz for XPIC 2+0. > Different radios, different price points, different tools in the tool box. > Thank you, > Daniel White > afmu...@gmail.com > Cell: +1 (303) 746-3590 > Skype: danieldwhite > Social: LinkedIn : Twitter > From: Af [mailto:af-boun...@afmug.com] On Behalf Of Mike Hammett > Sent: Tuesday, October 20, 2015 8:04 AM > To: af@afmug.com > Subject: Re: [AFMUG] Mimosa B11: Exactly what does the mounting look like? > Yes, I know I'm arguing with someone that does this as their job. > How is a TDD system any different from a licensing and interference > perspective > than licensing all channels in use in both directions? Instead of one high and > one low, each in opposing directions you license one high and one low in both > directions (for 1x 80)? When calculating interference in the future, you just > see that channel at that site in that direction is Tx and treat it as such. > ----- > Mike Hammett > Intelligent Computing Solutions > http://www.ics-il.com > From: "Tim Hardy" < tha...@comsearch.com > > To: af@afmug.com > Sent: Tuesday, October 20, 2015 8:56:01 AM > Subject: Re: [AFMUG] Mimosa B11: Exactly what does the mounting look like? > 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 > > To: 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 >> From: "Mike Black" < mbl...@bamicrowave.com > >> To: 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 >> 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 >> 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 > 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 > This email has been checked for viruses by Avast antivirus software. > www.avast.com
