> I'm still in a quandry :) I am too <G>. The measured results are rather clear but I miss the "magic" results I saw with 4.16 ...
The "feeling" I get with 4.21 is that the Q has been reduced compared to 4.16 but since the quantitative data shows that's obviously not the case, I'll just need to continue working with it to see if I can regain the magic. Maybe it is just conditions ... noise levels have been a lot lower the last couple days but there haven't been as many weak signals either. 73, ... Joe, W4TV On 11/13/2010 11:48 PM, Wayne Burdick wrote: > Joe, > > If Lyle is using the same algorithm as before, and your results are as > indicated below (virtually a tie), I don't understand how you could be > hearing a "lack of ringing" in the new revision. I simply cannot hear > any difference myself, and I'm extremely picky. We have nearly 100 > people testing, and only two or three have perceived a difference, so > given the statistical evidence, I'd suggest that background noise > conditions are the variable here, not the firmware. Lyle has also > completely reviewed the DSP implementation -- no change. > > But since the customers are always right, I'm still in a quandry :) > > tnx > Wayne > > On Nov 13, 2010, at 6:27 PM, Joe Subich, W4TV wrote: > >> >>>> I'll count this as another vote in favor of adding the Variable Q >>>> setting... >> >> Not on your life. The lack of ringing on the newer version seems to >> go along with a general decline in effectiveness. If anything I'd >> prefer to see higher Q. >> >> Just for grins I reloaded 4.16 to make the same measurements using the >> XG-2 as I made on 4.21. Here is the comparison: >> >> BW 4.21 4.16 >> ------------------------- >> 0 dB 1 2 Hz >> -1 dB 8 9 Hz >> -6 dB 31 31 Hz >> -10 dB 52 49 Hz >> -20 dB 165 162 Hz >> -30 dB 345 351 Hz >> Gain 9.0 9.1 dB >> >> Unlike W4ZV, I found only a 3 Hz offset in 4.16 (the peak response >> was 3 Hz above zero beat - or the indicated spot/shift frequency). >> Even though the test results were generally the same within the >> measurement tolerances, I still feel the 4.16 version was more effective >> in on air listening. >> >> These measurements were generated with an XG-2 set for 1 uV with the >> K3 attenuator engaged for an effective signal level of -118 dBm. >> >> 73, >> >> ... Joe, W4TV >> >> On 11/13/2010 8:07 PM, The Smiths wrote: >>> >>> I'll count this as another vote in favor of adding the Variable Q >>> setting... At least a choice of 3 perhaps Wide, Med and Narrow. Even >>> if one perceives the APF as "less ringy" and comments on it being a >>> good thing, that means that they are happy to know that the Q got >>> widened out a little, and things seem to sound "better". >>> >>>> From: w5...@cybermesa.net >>>> To: li...@subich.com; elecraft@mailman.qth.net >>>> Date: Sat, 13 Nov 2010 21:19:46 +0000 >>>> Subject: Re: [Elecraft] K3 APF >>>> >>>> Joe wrote: >>>> >>>>> I did not make similar measurements with the original alpha >>>>> test version but this version seems subjectively less tight >>>>> than the original ... there is certainly less ringing with >>>>> this one but signals did not seem to "pop" like they did on >>>>> the earlier version when I tried it last night on 160/80/40. >>>> >>>> Joe, I agree with your subjective observation. No, the signals don't >>>> "pop" >>>> as much -- but there is less ringing. This is a trade-off, of >>>> course, and >>>> the precise balance of peak gain versus ringing is always going to be a >>>> matter of personal preference. >>>> >>>> I like this less-ringy version better, I think. Haven't had time to >>>> play >>>> with it a lot yet, but I will. I'm sure we will see many other >>>> opinions. So >>>> far, I think the current version is very smooth and adequately "peaky". >>>> >>>> (Opinion subject to revision upon more extensive usage.) >>>> >>>> Bill W5WVO >>>> >>>> >>>> -----Original Message----- >>>> From: Joe Subich, W4TV >>>> Sent: Saturday, November 13, 2010 20:35 >>>> To: elecraft@mailman.qth.net >>>> Subject: Re: [Elecraft] K3 APF >>>> >>>> >>>> I made a similar set of measurements ... using the XG-2 and >>>> the AFV/dBV capability ... >>>> >>>> I measure the peak at 1 Hz wide (e.g. -.1dB +/- 1 Hz) >>>> the 1 dB points are 8 Hz wide >>>> the 6 dB points are 31 Hz wide >>>> the 20 dB points are 165 Hz wide >>>> the 30 dB points are 345 Hz wide >>>> gain is right at 9 dB. >>>> >>>> The measurements were made on 40 Meters with the XG-2 set to >>>> 1 uV and the K3 attenuator activated yielding a -108 dBm test >>>> signal. >>>> >>>> I did not make similar measurements with the original alpha >>>> test version but this version seems subjectively less tight >>>> than the original ... there is certainly less ringing with >>>> this one but signals did not seem to "pop" like they did on >>>> the earlier version when I tried it last night on 160/80/40. >>>> >>>> 73, >>>> >>>> ... Joe, W4TV >>>> >>>> >>>> On 11/13/2010 1:24 PM, Bill W4ZV wrote: >>>>> >>>>> For my own curiosity I did some measurements of the latest APF. >>>>> They agree >>>>> with >>>>> measurements of the first release with the exception that the >>>>> filter peak >>>>> is >>>>> now >>>>> zero beat instead of +10 Hz: >>>>> >>>>> Zero beat = 7040.021 >>>>> Flat passband = 021-020 (both 0.0 to -0.1 dB) >>>>> -1 dB passband = 026-018 (-1.2 dB and -0.8 dB) >>>>> -6 dB passband = 037-009 (-5.8 and -6.0 dB) >>>>> >>>>> Flat = 2 Hz BW (at zero beat) >>>>> -1 dB = 8 Hz BW >>>>> -6 dB = 28 Hz BW >>>>> >>>>> I didn't measure the -6 dB BW carefully on the first pass since I >>>>> was more >>>>> interested in the -1 dB BW, but this looks similar and agrees with >>>>> Lyle's >>>>> 30 >>>>> Hz >>>>> design goal. As mentioned previously, the -1 dB BW is important when >>>>> trying >>>>> to >>>>> detect signals below the noise floor since the human ear can detect >>>>> this >>>>> difference in marginal conditions. >>>>> >>>>> I also checked the gain (APF vs not) which I didn't do >>>>> before...+9.1 dB >>>>> which is >>>>> very close to Lyle's design goal of +9 dB. >>>>> >>>>> Nice job Elecraft! >>>>> >>>>> 73, Bill >>>>> >>>>> >>>> ______________________________________________________________ >>>> 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 >>> >> ______________________________________________________________ >> 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