With all the discussion about what may or may not be a "thump" and what it actually sounds like, I'm a bit surprised nobody has bothered to post a simple recording of it so that the rest of us don't have to guess at what you're hearing.
Dave AB7E Merv Schweigert wrote: > I posted that I could not duplicate the thumps on #2603. After trying a > few more times > I am hearing exactly what Mike describes, and after talking with Toby, > it may be a > difference in terminology, at least on my part. I hear the same thing > but I describe it > as pops or clicks, and as Mike says it seems to be from the high > background noise, > not that I have a high level of background noise, mine is S2, but from > the high level > of the RF gain control, I never hear these artifacts due to the way I > use the AF/RF > controls, my AF is usually set about 12 o'clock and RF about the same, > I use the > RF as the gain control, I think this was described many times in the > past by others. > The thump is also noticeable if there are signals on the band inside the > passband, I have > the monitor volume set high enough that it equals those signals in > volume so the > thump is less noticeable. > Some of these anomaly are hard to define, and finding a word to > describe the sound > is difficult. To me its pops or dull clicks, others its thumps, but we > agree we are > hearing something. > 73 Merv KH7C > > >> I can duplicate what might be called QSK thumps with high volume settings >> and using earphones or speakers. I have the choke change but have not >> modified low frequency response with larger caps. I think the thumps come on >> key up not key down. >> Everything is fine when I have the volume set at a normal level. I begin >> hearing thumps at a volume setting of 11 O'Clock. >> >> What I believe I am hearing though is not an artifact but just high band >> noise between dits that give an impression of thumps. The high band noise is >> being gated by TR switching. I suspect if I didn't live in a high noise >> environment I wouldn't here this. >> >> Mike Scott - AE6WA >> Tarzana, CA (DM04 / near LA) >> NAQCC 3535 >> K3-100 #508 / KX1 #1311 >> >> I sat down in TEST mode and tried all the combinations you mentioned again >> and can't produce thumps. I even tried every possible combination of AF/RF >> and MON levels with no thump. >> >> So I'm sri to say obviously something is different between our rigs and >> setups, but I can't imagine what. >> >> The only audio mod involving a change on the main board is to change a >> choke, not a cap. It reduces the resistance of the choke to improve the >> voltage regulation at the AF Amp. I've made that too. When I said my K3 was >> "stock" Elecraft, it does have the Elecraft-approved and documented mods >> made while writing the app notes. >> >> I asked wondering if the capacitor changes some have made to improve the >> low-frequency response were making the low frequency 'thumps' stronger and >> audible. If you've not done them, we should have similar rigs. >> >> Ron AC7AC >> >> ______________________________________________________________ >> Elecraft mailing list >> Home: http://mailman.qth.net/mailman/listinfo/elecraft >> Help: http://mailman.qth.net/mmfaq.htm >> Post: mailto:[email protected] >> >> 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:[email protected] > > 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:[email protected] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
