While on 160m a few nights ago I heard loud key clicks and tracked it down to a ham just 1 mile away who was chasing a DX station. When he transmitted, my K3 was rendered totally deft from any signal within 10 Khz of him! My 200hz roofing filter, ATTN, preamp off and RFG down had no effect. I guess even the K3 has it's limits. Steve N4LQ n...@carolina.rr.com ----- Original Message ----- From: "David Gilbert" <xda...@cis-broadband.com> To: "Ron D'Eau Claire" <r...@cobi.biz> Cc: "'Elecraft Reflector'" <elecraft@mailman.qth.net> Sent: Tuesday, December 01, 2009 1:29 PM Subject: Re: [Elecraft] K3: killing RX key clicks
> > 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 -------------------------------------------------------------------------------- No virus found in this incoming message. Checked by AVG - www.avg.com Version: 9.0.709 / Virus Database: 270.14.88/2538 - Release Date: 12/01/09 02:59:00 ______________________________________________________________ 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
