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On Jun 7, 11:36*am, Jim Lux wrote:
* Have you a link to the data and test methodology? I summarized the data from three CA 75m mobile shootouts at: http://www.w5dxp.com/shootout.htm I don't recall a test methodology being published. The test receiver consisted of a ferrite loop antenna in the far field feeding a lab- grade RF voltmeter. The power incident upon the 75m mobile antenna system was assumed to be forward power minus reflected power on the coax to the antenna system, measured using two Birds. The receive results were normalized accordingly. I may have left out a detail or two. The SG-230 plus 11.5 whip at -12 dB was equal to a 75m hamstick. I entered both the top-rated (0 dB reference) antenna and the (-12 dB) autotuner+whip on the same vehicle. When I "superposed" all of the three results, I assumed 0 dB for each top-rated antenna and let the rest fall where they might. That may or may not have been a reasonable assumption. I suspect the SG-230 is designed to dissipate 100 watts (using large #2 material powdered-iron toroids). During one shootout episode, I forgot to attach the antenna to the mobile mount. The SG-230 faithfully tuned to close to a 1:1 match on the input - with a near- infinite SWR on the output. It was a damp foggy day and the mobile mount arced. That taught me not to mount the SG-230 unobserved in the attic. :-) -- 73, Cecil, w5dxp.com |
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