Getting 60 dB FB on a small dish at 6 GHz is terribly difficult to achieve. It is terribly difficult to measure too....
From: Tim Hardy Sent: Friday, April 20, 2018 6:37 AM To: <[email protected]> Subject: Re: [AFMUG] 18GHz Licensed Link best power and Rx Sensitivity Some clarification of the rules needed here. 1. 3 & 4 foot antennas are allowed in upper 6 GHz in certain areas. In the late 70s / early 80s, the FCC designated congested areas in the 6.7 GHz band where Category A or better antennas must be used. The Category A beamwidth and gain requirement cannot be met by antennas less than 6 foot in diameter. 2. The minimum path length rule is also often misunderstood. FCC Rule 101.143 specifies 17 km for bands between 1850 and 7125 MHz and 5 km for bands between 10550 and 13250 MHz. But in both instances, shorter paths can be licensed as long as the EIRPs are limited as specified in paragraph B of the same rule part. No exceptions for entities or waivers required. 3. The smaller antennas that are now allowed in 6 GHz are required to meet Category B2 which has relaxed beamwidth and pattern requirements for angles less than 100 degrees and tighter requirements for angles greater than 100 degrees. The angles greater than 100 degrees must provide at least 60 dB of discrimination. AFAIK, Commscope, RadioWaves and RFS are the only manufacturers that meet these requirements. Tim Message: 2 Date: Thu, 19 Apr 2018 17:59:12 -0700 From: "SmarterBroadband" <[email protected]> To: <[email protected]> Subject: Re: [AFMUG] 18GHz Licensed Link best power and Rx Sensitivity Message-ID: <[email protected]> Content-Type: text/plain; charset="utf-8" Thanks. I remember the 3 foot ruling. Never heard of a 2 foot rule, and yes I had forgotten the minimum distance requirement. It seems the 5Km rule is being ignored, I am sure people are reporting short links with AF11?.. From: Af [mailto:[email protected]] On Behalf Of George Skorup Sent: Thursday, April 19, 2018 3:29 PM To: [email protected] Subject: Re: [AFMUG] 18GHz Licensed Link best power and Rx Sensitivity Yeah, no. The minimum diameter in the L6 band is 3-foot and >/=70dB F/B ratio. I believe only a few Radiowaves and Andrew/CommScope high-performance dishes meet that spec. I believe that was part of the same change that allowed 60MHz channel bandwidth. The upper 6GHz band is still limited to 30MHz channels and 6-foot or larger antennas. Also, the minimum path length for both lower and upper 6GHz bands is 17km. 11GHz is 5km. I believe there are special considerations and waivers to this for things like public safety agencies and such.
