Bud wrote: "... One reason practical SWR meters don't read the same value of SWR on a line -- even at the same point on the line -- is because different circuit designs may have different amounts of error, or inaccuracy, for different amplitudes and combinations of R and X...."
------------------ That's a very important point. SWR meters are not highly accurate devices because they do not need to be highly accurate devices. With virtually any popular antenna system, especially on HF, a moderate SWR has no significant impact on performance. My first SWR "meter" was two small light bulbs connected to short lengths of "twin lead" (300 ohm TV feed line) taped to the same sort of feed line used to feed RF to my antenna. When the SWR was low, one bulb glowed a lot brighter than the other when I transmitted. That's all I needed. More than that was TMI (too much information), as they say. The advent of meters and now digital displays has only one advantage over the light bulbs; they provide a numerical readout of the presumed SWR at any given frequency. With them it's easier to see a significant change of SWR at that frequency from day to day that might indicate something amiss in the antenna system. That sort of monitoring is more important than ever since modern wide range antenna tuners will compensate for any changes, even a broken or shorted feed line between the rig and antenna. The 'red flag' isn't the actual SWR as much as it is an unexpected change in the indicated SWR. 73, Ron AC7AC ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
