On Dec 3, 2010, at 11:06 AM, Jan Erik Holm wrote: > Yes 99% of all CW stations clicks at the "break" side.
That makes perfect sense, Jan. If they are using simple IIR filters, the slope discontinuity is worse at the onset of switching than when it is at the end of the leading edge or trailing edge (visualize the RC constant diagrams that we learn in school :-). Now, the onset of switching states happens to occur at low power (zero power) on the rising edge of a CW pulse, so even if it is dirty, you are not putting out energy. But it the worst part of an RC filter occurs at the highest power location at the trailing edge of a CW pulse. If the click spectra is mostly coming from slope discontinuities, the energy from the clicks are going to be much greater when the key is breaking than when the key is making. This is why a couple of us has said that it is not the "rise time" (or fall time) that is important, it is the n-th order discontinuities (slope discontinuity contributes more than higher order ones obviously, when you look at it as a Fourier series). Someone else can probably explain better than I can. I can't do it without using equations. English is my third language :-). 73 Chen, W7AY ______________________________________________________________ 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
