You made me think a bit. Consider 11 GHz. One 2 mile link and one 10 mile link. 15’ 34’ I presume the online tool is calculating 60% of the first fresnel zone.
So half that would be the opposite side of a right triangle. arc tan of 7.5/10560 = .04 deg arc tan of 17/52800 = .018 deg So double that for the diameter of the cone based on the distance and angle you have almost 1 full degree and a third of a degree. Pretty small circles. May as well call them a dot when viewing through the camera. From: [email protected] Sent: Wednesday, December 19, 2018 10:12 AM To: AnimalFarm Microwave Users Group Subject: Re: [AFMUG] Fresnel scope? I toyed around with this idea last night. I think the angle of view of most phones is too wide. Doing the rangefinder math for my iPhone 6s a 1 meter dish at 1 km would be less than 4 pixels across at full resolution (4032x3024). The 5.8 GHz fresnel radius would be 3.6 m or only 52 pixels. Of course, this would grow larger if calculated closer to the user—even as the fresnel zone shrank—but I don’t have the calculus chops to figure out the ideal size to indicate “this area should be clear no matter how far away” December 18, 2018 8:58 AM, [email protected] wrote: I guess you could run a calibration routine where you take a photo of some linear feature that exactly fills the frame and tell the phone how far away it is and how wide it is. From: Brian Webster Sent: Monday, December 17, 2018 10:09 PM To: 'AnimalFarm Microwave Users Group' Subject: Re: [AFMUG] Fresnel scope? Right and since you know the frequency and total path distance, if you used a laser range finder to put the spot on an obstruction you would know that distance and could calculate the size of the zone at that obstruction distance. Might be able to do some Pythagorean math on the other side of an obstruction to determine the width of the “hole” through to see if it is wide enough for the zone clearance at that distance? This might be a bit too much for an app that would work on all phones but I wonder if it would be easier to make it work on an outboard camera with the known lenses and rangefinder configuration and just use the phone to run the calcs. Thank You, Brian Webster www.wirelessmapping.com www.Broadband-Mapping.com From: AF [mailto:[email protected]] On Behalf Of Chuck McCown Sent: Monday, December 17, 2018 8:40 PM To: AnimalFarm Microwave Users Group Subject: Re: [AFMUG] Fresnel scope? I guess you could enter the distance of the link and the camera field of view. With that you could put some circles on the screen. From: Jeremy Sent: Monday, December 17, 2018 6:13 PM To: AnimalFarm Microwave Users Group Subject: Re: [AFMUG] Fresnel scope? What about integrating it with one of these laser rangefinders that are fairly cheap now? The tech exists to make this product work, but I am not sure if there is a big enough market to justify the R&D. On Mon, Dec 17, 2018 at 6:12 PM Chuck McCown <[email protected]> wrote: The challenge would be to know the distance to the obstructions. From: Steve Jones Sent: Monday, December 17, 2018 6:06 PM To: AnimalFarm Microwave Users Group Subject: [AFMUG] Fresnel scope? Anybody every toyed with making some kind of fresnel scope for installers? Like a rangfinder with a red, orange, yellow, and green opaque overlay that you dial your freq and range and it adjusts the rings? Having been doing the installers job for almost a year and seeing the "gap in the trees" theyve been shooting through, explains alot of the performance issues. A phone app would be cool cause you could do a field of vision screenshot. But i dont know how that could be calculated with much accuracy given the differences in cameras Would be really cool if the adjustable rings could be used to identify beneficial obstructions for mitigating destructive multipath. I cant see the concept being all that complicated, you would know the magnification, field of vision and distance from the eye. Making the circles adjust like miltiple irises would be a might bit complicated though. ---------------------------------------------------------------------------- -- AF mailing list [email protected] http://af.afmug.com/mailman/listinfo/af_af.afmug.com -- AF mailing list [email protected] http://af.afmug.com/mailman/listinfo/af_af.afmug.com ------------------------------------------------------------------------------ -- AF mailing list [email protected] http://af.afmug.com/mailman/listinfo/af_af.afmug.com ------------------------------------------------------------------------------ -- AF mailing list [email protected] http://af.afmug.com/mailman/listinfo/af_af.afmug.com -------------------------------------------------------------------------------- -- AF mailing list [email protected] http://af.afmug.com/mailman/listinfo/af_af.afmug.com
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