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*Subject*: Re: [amsat-bb] Using C band polar mounts w/ ao-40*From*: "Edward R. Cole" <al7eb@xxxxxxxxxxxxx>*Date*: Mon, 23 Apr 2001 14:11:37 -0800

>From: "Vince R." <vincesr@ij.net> >What is the theoretical gain of my "six" foot mesh TVRO dish at 2.4Ghz? >Beamwidth? Links to equations/tables/shareware dish calculators >will be welcomed! > >Vince Risalvato >KD7AI Vince, The formula for dish gain is: G = 10 Log [e*12.56*(diameter)^2/(wavelenth)^2] in dBi e = is the efficiency and ranges from 0 to 1 [for zero to 100%] I set e = 0.5 Diameter and wavelength should be in the same units [feet, or inches, or meters,...] Your dish at 2400 MHz: wavelength = 300/2400 = 12.5 cm diameter = 6*12*2.54 = 183 cm diameter/wavelength = 14.64, and squared = 214.3 solving the expression inside the bracket = 1356 in dB that is 31.3 dBi Beamwidth = 57.3 Wavelenth/Diameter = 3.9 degrees This is included in an Excel spreadsheet called g-t.xls found at: http://www.seatileague.org/software/spreadsh.htm Ed ---- Via the amsat-bb mailing list at AMSAT.ORG courtesy of AMSAT-NA. To unsubscribe, send "unsubscribe amsat-bb" to Majordomo@amsat.org

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