This shows the problem. The purple test data shows that my 3 foot dish just barely fit under the CAT A spec for 11 GHz. My 2 footer just barely fit under the CAT B line. The larger the dish, the lower the sidelobes. Most of the compliance issues are with the first few sidelobes and then at the back side for F/B.
From: Daniel White Sent: Tuesday, November 08, 2016 5:28 AM To: [email protected] Subject: Re: [AFMUG] Class A and B antennas Mostly answered… but I’ll take a stab: Class A vs Class B is about side-lobe suppression and F/B ratio. ETSI classes are the same way – and Class 4 antennas as Eric pointed out are a rare beast - For 11GHz, the smallest Class A antenna is the VHLP800 (2.6ft). Most 3ft antennas are actually a little bit bigger than 3ft (99cm) - For 18GHz, the smallest Class A antennas I am aware of are 2ft - Minimum distance for 11GHz and 6GHz is covered under FCC Part § 101.143, with the minimum distance being 5km (roughly 3.12mi). If you want to go shorter, than the max coordinated power you can use is calculated like this: EIRP = MAXEIRP–40*log(A/B) dBW EIRP = The new maximum EIRP (equivalent isotropically radiated power) in dBW. MAXEIRP = Maximum EIRP as set forth in the Table in Section 101.113(a). *This is +55dBW for 11GHz* A = Minimum path length from the Table above for the frequency band in kilometers. *This is 5km for 11GHz* B = The actual path length in kilometers. NOTE: For transmitters using Automatic Transmitter Power Control, EIRP corresponds to the maximum transmitter power available, not the coordinated transmit power or the nominal transmit power. Daniel White Managing Director – Hardware Distribution Sales ConVergence Technologies Cell: +1 (303) 746-3590 [email protected] From: Af [mailto:[email protected]] On Behalf Of SmarterBroadband Sent: Monday, November 7, 2016 6:34 PM To: [email protected] Subject: [AFMUG] Class A and B antennas Does anyone make a 2 foot Class A antenna for 11 GHz? Or is 3 foot the minimum. Does anyone make a 1 foot Class A antenna for 18 GHz? Or is 2 foot the minimum. Is there a minimum distance for a 11 GHz link? Thanks Adam Virus-free. www.avast.com
