Paul, The K4's DSP smoothly ramps audio up/down during muting. There's no "clamp."
The artifacts in the recording are not coming from the K4; they're probably due to RFI getting into the external recording device's cables, as Bob mentioned in his posting. Wayne > On Jun 23, 2020, at 9:11 AM, Paul Hvidston <[email protected]> wrote: > > Just sounds like the audio muting during key-down. The K4 speaker > probably rolls off below 300Hz while your recording has higher fidelity. > External audio devices would have to roll off the low frequency to avoid > it. I bet if the K4 used a VCA rather than a simple clamp you probably > would not hear this on the line-out during keying. No idea if it is > simple hardware or a DSP operation (easily fixed). Either way, the K4 is > impressive. > > 72 de Paul/N6MGN > > On 6/23/2020 7:23 AM, Victor Rosenthal 4X6GP wrote: >> I certainly hope the clicking I hear on the sidetone is an artifact of >> the recording process, or something that will go away with the >> production version of the K4! >> >> >> 73, >> Victor, 4X6GP >> Rehovot, Israel >> Formerly K2VCO >> CWops no. 5 >> http://www.qsl.net/k2vco/ >> . >> On 23/06/2020 12:41, Bob Wilson, N6TV wrote: >>> Summary: The K4D Receiver Audio and QSK performance seems >>> outstanding -- >>> I'm sold. >>> >>> I hesitated to order a K4 until I could hear how one sounded in "real >>> world" pileup conditions, compared to my trusty 11-year old K3s (S/N >>> 1494 >>> and 1495 with KSYN3A upgrades). >>> >>> Well, here is a short recording I made while operating a K4D Field Test >>> unit during the All Asian CW Contest this past weekend, so you can >>> have a >>> listen to the QSK performance and the audio tones when several >>> stations are >>> calling on about the same frequency all at once, which is the typical >>> "pileup mush" situation that has been so difficult for most modern >>> radios >>> to handle (including the K3): >>> >>> https://www.kkn.net/~n6tv/Pileup_Audio_on_K4D_Field_Test_N6TV.mp3 >>> >>> (Headphones recommended). >>> >>> With 2 or 3 guys calling, it seemed *so* much easier to pick out >>> callsigns >>> with the K4D, compared to my K3, especially when they were very close in >>> frequency, which was often. The audio distortion and "beat note >>> buzzing" I >>> still occasionally hear on the K3 is not heard on the K4. *This alone is >>> reason enough for me to order a second K4D* for SO2R contesting. >>> >>> Note: The "thumps" and clicks you hear in the recording while I'm >>> transmitting with full QSK are mostly a side effect of the analog >>> recording >>> method used (rear headphone jack, long cable, ungrounded radio, and >>> microHAM MK2R+ sound card). I think some RF is still getting into the >>> MK2R+ despite lots of ferrites. The "thumps" are not heard in the front >>> panel headphone jack of the K4. The stereo USB Sound in the K4D >>> won't have >>> these issues. >>> >>> I also toggled PRE1 and NR (level 4) when a weak one would call, and it >>> really seemed to help pull them out of the noise. I put both >>> receivers on >>> the same frequency and used A/B to toggle both settings ON and OFF at >>> the >>> same time with a single tap (Main RX had PRE OFF and NR OFF, Sub RX had >>> PRE1 ON and NR ON, and I would swap them). I modified my Win-Test >>> scripts >>> <https://bit.ly/wtscripts> so I could swap A/B from the keyboard of my >>> logging program. I've also made scope control work from the Win-Test >>> keyboard, as with my P3 scripts. The radio responds to CAT commands >>> instantly, as does the touch screen display. >>> >>> Unlike the K3, I could keep the RF Gain at MAX and hear no real problem >>> until the bands got really noisy, then backing it off helped a bit, >>> as did >>> the attenuator. But I like the way the fast AGC worked. Loud stations >>> never hammered my ears, and there's a new "AGC attack time" setting >>> that we >>> don't have in the K3 that will require further experimentation. >>> >>> As for QSK, I went back and forth between QSK ON and QSK OFF, Delay >>> 0.00. >>> There's a huge difference. QSK OFF Delay 0.00 is much quieter, but I >>> like >>> to hear more between elements. >>> >>> QSK performance was *way* better than the K3, especially at high >>> speed (I >>> went up to 39 WPM). Amp. is a KPA1500. No CW jitter was observed, >>> so "CW >>> QRQ" mode is no longer needed to send clean CW at high speed with either >>> internal or external keying. I used 5 ms of keying compensation and got >>> good reports from that, but I need to get out my scope and make some >>> measurements. >>> >>> I figured I would eventually want to order the K4 "HD" model, but I >>> may not >>> need it. So far the receiver performance seems really good, even when >>> getting close to loud signals. But I don't have a way to make the >>> careful >>> receiver performance measurements that Rob Sherwood, NC0B, can make. >>> >>> The band scope has much finer resolution than the P3 or an IC-7851, >>> but I >>> still need to experiment with an external HDMI monitor, which will >>> provide >>> even more pixels for the band scope. >>> >>> Physically, a K4D is smaller than the K3/P3 combo. side by side, and >>> it's >>> only about 3/4" taller and maybe an inch deeper. >>> >>> The K4 buttons have a very nice tactile feel, much improved over the K3. >>> Every knob except AF Gain seems to be an optical encoder rather than >>> a pot, >>> which means there is potential to control just about everything from >>> your >>> logging program keyboard, without having to touch the radio. >>> >>> The "tap to tune" feature of the waterfall display seems to work well >>> for >>> making big frequency movements. I need to try it with a USB mouse. >>> Better >>> than that, there's a new method to automatically adjust the band noise >>> level on the scope so you don't have to constantly fiddle with a "REF >>> LVL" >>> setting as we do on the P3. >>> >>> There's more to write, but this post is long enough already. >>> >>> In sum, I know we've all been waiting a long time for the K4 to be >>> delivered. I think it will be well worth the wait, and that your >>> patience >>> will be rewarded. Meanwhile, me and my fellow volunteer Field >>> Testers will >>> be very busy trying to find all the bugs so that you won't have to. :-) >>> But as delivered to us, it seems very stable, and very usable. Most >>> of the >>> major features are working quite well at this point. >>> >>> 73, >>> Bob, N6TV >>> ______________________________________________________________ >>> 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 >>> Message delivered to [email protected] >>> >> ______________________________________________________________ >> 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 >> Message delivered to [email protected] > > ______________________________________________________________ > 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 > Message delivered to [email protected] ______________________________________________________________ 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 Message delivered to [email protected]
