Re: [Elecraft] Distortion
Hi Hans You seem to have a known problem - with a known fix: Weird behavior around 7185 kHz. It is due to interaction between the VFO and the PLL reference oscillator. Search for '7185' in my list http://la3za.blogspot.no/p/la3za-unofficial-guide-to-elecraft-k2_5502.html http://la3za.blogspot.no/p/la3za-unofficial-guide-to-elecraft-k2_5502.html and you will find some links that will help you. - Sverre, LA3ZA K2 #2198, K3 #3391, LA3ZA Blog: http://la3za.blogspot.com, LA3ZA Unofficial Guide to K2 modifications: http://la3za.blogspot.com/p/la3za-unofficial-guide-to-elecraft-k2.html -- View this message in context: http://elecraft.365791.n2.nabble.com/Distortion-tp7586001p7586004.html Sent from the Elecraft mailing list archive at Nabble.com. __ 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 Message delivered to arch...@mail-archive.com
Re: [Elecraft] Distortion
Hans, That sounds like the old WAOF (Weird At One Frequency) problem. That is the region where the PLL oscillator and VFO frequencies cross paths near 7185 kHz. See http://www.elecraft.com/Apps/Alert11_WAOF.html. Note that this alert refers to older version A K2s, you will not find C70 on your board. If this is your problem, the audio signals will sound rather like they are 'under water' If you have something different, then ask again. With a new K2 layout, that seldom happens, so check to be certain D16 is mounted flush with the board. In addition, the components mounted on the bottom of U4 (C88, RFC15 and C91) should have leads as short as possible - make certain they are connected to the correct pins. You may need to trim all leads in the vicinity of U4 so there is nothing that would act as an 'antenna'. 73, Don W3FPR On 3/26/2014 1:44 PM, Hans Elfelt Bonnesen wrote: K2 Audio Distortion. My otherwise flawless K2 # 7359 is found to have serious audio distortion problems on received and transmitted signals on 40 meter. The problem appears as soon as I go above 7171 kHz. On 7182 the problem makes SSB contacts impossible Lower frequencies do not suffer. Why ? I still haven’t checked the problem on other bands. __ 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 Message delivered to arch...@mail-archive.com
Re: [Elecraft] Distortion
Nice list you have, Sverre. My K2 (#380) didn't suffer from this malaise (I tested it as specified) but I've done most all the others. Most recent was the AF pot mod: No parts, but fussy work on the three main boards -- and well worth the effort! 73, Phil W7ox On 3/26/14, 11:48 AM, Sverre Holm (LA3ZA) wrote: Hi Hans You seem to have a known problem - with a known fix: Weird behavior around 7185 kHz. It is due to interaction between the VFO and the PLL reference oscillator. Search for '7185' in my list http://la3za.blogspot.no/p/la3za-unofficial-guide-to-elecraft-k2_5502.html http://la3za.blogspot.no/p/la3za-unofficial-guide-to-elecraft-k2_5502.html and you will find some links that will help you. - Sverre, LA3ZA K2 #2198, K3 #3391, LA3ZA Blog: http://la3za.blogspot.com, LA3ZA Unofficial Guide to K2 modifications: http://la3za.blogspot.com/p/la3za-unofficial-guide-to-elecraft-k2.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 Message delivered to arch...@mail-archive.com
Re: [Elecraft] Distortion
Phil Wheeler-2 wrote Nice list you have, Sverre. Thanks! Since August last year I have updated the list (link in my signature field) and added several photos to make it easier to navigate. - Sverre, LA3ZA K2 #2198, K3 #3391, LA3ZA Blog: http://la3za.blogspot.com, LA3ZA Unofficial Guide to K2 modifications: http://la3za.blogspot.com/p/la3za-unofficial-guide-to-elecraft-k2.html -- View this message in context: http://elecraft.365791.n2.nabble.com/Distortion-tp7586001p7586007.html Sent from the Elecraft mailing list archive at Nabble.com. __ 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 Message delivered to arch...@mail-archive.com
Re: [Elecraft] Distortion while using NB?
JIM DAVIS wrote: With alot of the newer rigs with noise-blankers it's always been the case whereby when they are activated there's always a small amount of distortion that's injected into the audio we hear, either via our speaker or from the headphones! So what I'm asking is it possible (eventually) that through firmware manipulation that that (irksome by-product) will ever be able to be eliminated or at least smoothed out a tad bit more??? Hi Jim, The answer depends on the type of noise. An I.F. blanker like the K3's can, in many cases, completely remove pulse noise such as that from power lines without any type of audio artifact. But some noise has such a high duty cycle that blanking it creates unavoidable holes in the signal. Also, an I.F. blanker can generate audible IMD if there happen to be high-amplitude signals in its input passband. To mitigate these problems, the K3 provides a wide range of blanking pulse width and sensitivity settings in its I.F. blanker, and also provides a DSP-based blanker that has many possible settings. The DSP blanker is far less likely to be impacted by off-channel signals because it is post-crystal-filter. In many cases the I.F. and DSP blankers can be used together to optimize noise rejection. We're always looking at new noise blanking techniques for both the I.F. blanker (hardware) and the DSP blanker (firmware). In the future we may be able to offer adaptive blanking and signal reconstruction either at I.F. or DSP. Any hardware advances would be easily retrofittable to existing K3s because the KNB3 is a separate module, and firmware improvements are always free of charge. 73, Wayne N6KR --- http://www.elecraft.com __ 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
