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'tis possible that it could have that kind of gain, as the reference
point (compared to Dipole (dBD), Isotropic (dBI), or WET NOODLE dB(?)) was neglected in the gain statement! In fact might be even better than 27 dB (?) when compared with a wet noodle, but that has no bearing on any credible gain! That ANY antenna would have a gain of some 400 TIMES a dipole, or even an isotropic (Point source) would take up considerable acreage at 2 meters! A typical moonbounce station uses about 20 dBD gain , and these are multiple yagi antennas. see: http://www.bigskyspaces.com/w7gj/longyagi.htm for a 19 dBD gain 2 meter yagi, and note the length! (98-1/2 feet long!) and also look for VE7BQH - These guys have verifiable antenna gains and know their stuff! when ANY antenna claims more than 10-11 dB I gain ,be very suspicious of the claims, also, make sure to see WHAT that gain is compared (referenced) against! This is at least one of the reasons that the ARRL is loath to allow gain claims by advertizer, unless they have been verified by independant sources. Jim NN7K Pierre Desjardins wrote: Hi to all I read somewhere that the dual rhombic could give a gain of almost 27 db using these dimension for 144,2 mHz: L1- 29.5 ft, L2- 50.67 ft, X- 52.2 degrees, Y- 37.7 degrees, R1/2 660 ohms noninductive, Ht: 12.29 ft, Elevation angle: 7.5 degrees, Vertical beamwidth: 5.5 degrees and Horizontal beamwidth: 8.5 degrees. Has anyone ever verified this? Here, using simulation with EZNEC+, I get about 15 dBi in free space and much lower on real ground. Am I missing something? Thanks for your answers 73 de Pierre VE2PID |
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#2
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"Jim - NN7K" wrote in message news ![]() 'tis possible that it could have that kind of gain, as the reference point (compared to Dipole (dBD), Isotropic (dBI), or WET NOODLE dB(?)) THATS IT! the ultimate reference. I hereby dub that measurement the dBwn which will from now on be used to get the best gain figures for advertising in anything except QST. |
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