I agree, I like the newer version as the ringing is much less now. Jim K4JAF
----- Original Message ----- From: "K9ZTV" <[email protected]> Cc: <[email protected]> Sent: Saturday, November 13, 2010 4:29 PM Subject: Re: [Elecraft] K3 APF (alpha 4.21) >I agree with Joe. > > My first impression was a "quieter" APF (if that's the right word). The > "peaking" is certainly there, and signals that are not copyable at 50 > cycles are definitely copyable with the new APF activated (provided > there is a copyable signal at all). But the peaked signal doesn't take > your breath away like it did on the earlier version. Frankly, I prefer > this newer "tamed" (if you will) iteration. It certainly has less > ringing. You can't have both "blasting" and "no ringing" at the same > time. There has to be a sweet spot and I believe version 4.21 nails it. > > I think there was some early confusion about what exactly is "frozen" > when the APF is turned on. It is the SHIFT that is locked, not the > WIDTH. The WIDTH control is still fully functional in APF mode with the > bandwidth still being clearly indicated both numerically (0.05 and up) > and by the normal width-varying graphic. When the APF is turned on, the > normal DUAL PB icon we have grown used to that incorporates > upward-pointing winglets is still displayed, but in APF mode the > winglets are positioned at the extreme ends of the line and are fixed. > They do not change position when the WIDTH control is rotated (as they > do when in normal DUAL PB mode). The middle-bars between the winglets > that show passband width DO change (as they always have) to visually > indicate the change of bandwidth. Fixing the winglets and locating them > at the far ends of the graphic display is a great idea and gives further > feedback that you are definitely in APF mode and not DUAL-PB mode. I > doubt anyone will confuse the two because (as in the earlier version) > you have to enable the APF mode in menu item CONFIG: DUAL PB. > > The SSB problem in version 4.18 that required higher settings of CMP and > ALC has been fixed. My MH2 microphone delivers the recommended 5-7 bars > of ALC and 2-3 bars of CMP at MIC=16 and CMP=13. These are the nominal > settings I have always run when circumstances force me to pull the mic > out of the drawer. For some reason the boys on the Missouri SSB Traffic > Net get real agitated when I check-in using a paddle. > > Great job, Lyle, et al. > > 73, > > Kent Trimble, K9ZTV > SN 21 > > > > > > > > On 11/13/2010 2:35 PM, Joe Subich, W4TV wrote: >> 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:[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
