Don, I downloaded the software, and found I could get my SSB OPT1 filter looking great until I turned on the AGC in USB!
Well I did solve it. It was a poorly aligned L34 causing the problem. I had read on this list that L34 was very broad and did not do much. Not at all true! Now turning AGC off and on does what you would expect. I am going to work though with the new software to better tweak things! Thanks! Chuck K8LBH > On Jan 14, 2020, at 2:52 PM, Don Wilhelm <donw...@embarqmail.com> wrote: > > Chuck, > > Your guess that the BFO is positioned inside the filter passbaad is likely > correct. > > Do you have the SSB FL1 filter set to OP1? If not, try that first. Many > times the filter on the RF Board (used for more narrow filter settings) > becomes VERY wide - much wider than indicated by the K2. It depends on the > exact characteristics of the varactors. > > If you are using the SSB OP1 filter, then check the capacitors around the > KSB2 filter crystals for proper values. An improper capacitor will distort > the passband shape and can make the passband quite wide. > > The best way and more certain way to analyze the problem is to look at the K2 > audio with an audio spectrum analyzer like Spectrogram running on your > computer and band noise fed into the K2 antenna (no signals, just noise) > > You can download Spectrogram from my website www.w3fpr.com (scroll to near > the bottom of the home page to find the local links). If you do not use > Windows, there are audio spectrum analyzers for other operating systems. > Instructions for setting up Spectrogram 5.17 and using it to align the > filters can be found on Tom Hammond N0SS (SK) website preserved at > http://www.mmccs.com/mmarc/n0ss/k2_filters_using_gram_v5r17.pdf. > > 73, > Don W3FPR > > On 1/14/2020 1:22 PM, myflyertra...@cfl.rr.com wrote: >> Hello, >> I have been working on a new K2 the last couple of months. SN 7927 >> Yesterday I finished and installed the KSB2 SSB adapter. >> I have been mostly listening. All seemed normal with receive on 80 and 40 >> meters, on LSB. >> But, as soon as I go to USB on any band below 21 mhz, or LSB 21 and above, >> the S meter goes to nearly full scale, and the receiver is desensitized. If >> I turn off the AGC, the receiver seems to work normally receiving both LSB >> and USB. >> I have checked the BFO values and used the default value of 4916.3 for USB >> and 4913.5 for LSB. >> No setting of the USB BFO seems to solve the issue. I can change the value >> and drop the S meter with AGC on and hear the Receiver apparently return to >> normal, but then I can’t tune USB and the number I am using then is close to >> the LSB value. >> Why the receiver works normally with AGC off, but not with AGC on on OP1 >> filter is puzzling to me. Everything is normal on the K2’s internal filters. >> I assume this has something to do with the crystal filter and BFO >> frequencies, but no idea where to go. >> Any ideas would be appreciated. >> 73 Chuck K8LBH ______________________________________________________________ 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