I'll accept all of that, but it still doesn't change the fact that there are some rigs out there that generate bad key clicks for no reason other than the fact that their users either don't realize it or don't care enough to fix them.
When I first received my Icom 756Pro (now my backup rig) several years ago I discovered that the default rise/fall times (adjustable in one of the menus) was set to 2 msec (!). That's unconscionable, but I'll bet the majority of Icom users never bothered to check it. Many of the Yaesu rigs generate horrible key clicks unless their users have performed a simple hardware modification on them (see the info at W8JI.com). I operated about 36 hours in the contest this last weekend and made over a thousand contacts using the 8-pole 250Hz roofing filter. Many times I'd be running a frequency within 200 Hz of a S9+30db station without even knowing he was there. Other times I'd hear key clicks (loud enough to cover the dits in callsigns I was trying to copy) from stations I couldn't even find while tuning with the subreceiver! One large M/M operation had great sounding signals on all bands except 15m, where the key clicks were objectionable two KHz away even when their signal was S5-S7. At least in that case they have promised to find the problem and fix it. Actually, there is a third reason why some stations have bad key clicks. They admit they do it on purpose in a contest because it gives them more elbow room. In my experience with the K3 in several major contests since I bought it last January, the very great majority of bad signals I've heard on the air have been due to the TX on the other end, not the RX on my end. 73, Dave AB7E Ron D'Eau Claire wrote: > Key clicks can be generated by several different mechanisms within the > receiver itself. Paradoxically, it's easier to produce false clicks with a > high performance receiver than it is with a lesser receiver. > > These have nothing to do with the transmitted signal. > > The first line of "defense" is to turn off the Preamp and turn on the > Attenuator to reduce the overall strength of the signals. Next is to set the > AGC to "Slow" to ensure a strong signal isn't within the roofing filter > bandpass and triggering the AGC while the variable DSP filter is set narrow > so the beat note isn't heard. In some cases using the RF gain to control the > level helps a great deal. Another approach is to use a narrower roofing > filter or to shift your bandpass so the edge of the roofing filter is very > close to the desired signal on the side toward the interfering station and > as far from the interfering station as possible. Shifting the bandpass may > require you open up your DSP bandwidth to continue to hear the desired > signal or shifting the DSP filter position within the roofing filter > bandpass. > > And, remember, "clicks" are an essential component of a CW signal. They are > the sidebands created by modulating (keying) the signal. Very careful > shaping of the keying envelope, such as used in the K2 and K3, can minimize > clicks while maintaining an easily readable signal, but the only way to > completely eliminate clicks is to not key the signal at all. With a really > high-performance you can snuggle up very close to a signal, as many here > have noted. When you do that, you're much more likely to hear the essential > clicks required for good keying. > > 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 ______________________________________________________________ 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
