K2 Filter settings
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Thrilled to get my K2 working on 7 MHz receive but I seem to have a problem with filter settings.
Everything has checked out according to the book - no problems at all (even my home-wound coils seem to work!!) I have set up the filters exactly according to pages 88 and 89. On Filter 1 the rx sounds great - plenty of gain, clean signals. On the other 3 filters it sounds like I am listening through a dense fog - I can tell the bandwidth is far narrower than F1 but signals are weak and it sounds as if the filters are overlapping each other (if you know what I mean). I have checked settings again and all look OK. Does anyone recognise this problem please? I am reluctant to proceed until I have sorted it out. 73 Nick G3RWF _______________________________________________ Elecraft mailing list Post to: [hidden email] You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com |
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Nick,
I wholeheartedly second this. I followed the manual and noticed the same thing you did. When I hooked up Spectrogram I could clearly see that the narrower filters were off center. I adjusted while watching the Spectrogram screen and things sound *much* better. Craig AC6NN -------------- Original message ---------------------- From: "Don Wilhelm" <[hidden email]> > > Nick, > > Sometimes the filters (particularly the narrower ones) do not respond well > to the initial numbers in the manual because the filter center may be > shifted a bit due to the particular set of matched crystals supplied. I > don't think you have a problem. > > There is a solution, and that is called 'Spectrogram', which will provide a > visual display of the filter shape and positioning on a computer screen. > Download the last freeware version (5.17) of Spectrogram from www.n0ss.net > and look at the instructions for using it on Tom's website or the Builder's > Resource page of the Elecraft website. > > You could let the filter alignemnt wait until you have the rest of the K2 > built and the KSB2 (if you added that) installed and then you can do a > complete dial calibration and filter alignment. Instructions for doing that > are on my website http://w3fpr.qrpradio.com > > 73, > Don W3FPR > > > -----Original Message----- > > > > > Thrilled to get my K2 working on 7 MHz receive but I seem to have > > a problem with filter settings. > > Everything has checked out according to the book - no problems at > > all (even my home-wound coils seem to work!!) > > I have set up the filters exactly according to pages 88 and 89. > > On Filter 1 the rx sounds great - plenty of gain, clean signals. > > On the other 3 filters it sounds like I am listening through a > > dense fog - I can tell the bandwidth is far narrower than F1 but > > signals are weak and it sounds as if the filters are overlapping > > each other (if you know what I mean). I have checked settings > > again and all look OK. Does anyone recognise this problem please? > > I am reluctant to proceed until I have sorted it out. > > 73 Nick G3RWF > > > -- > No virus found in this outgoing message. > Checked by AVG Free Edition. > Version: 7.5.446 / Virus Database: 268.18.11/723 - Release Date: 3/15/2007 > 11:27 AM > > _______________________________________________ > Elecraft mailing list > Post to: [hidden email] > You must be a subscriber to post to the list. > Subscriber Info (Addr. Change, sub, unsub etc.): > http://mailman.qth.net/mailman/listinfo/elecraft > > Help: http://mailman.qth.net/subscribers.htm > Elecraft web page: http://www.elecraft.com _______________________________________________ Elecraft mailing list Post to: [hidden email] You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com |
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In reply to this post by Nick G3RWF
And the Spectrogram marker you've set to your preferred
CW note (offset) will enable you to center the passbands on that frequency 73! Ken Kopp - K0PP [hidden email]. _______________________________________________ Elecraft mailing list Post to: [hidden email] You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com |
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In reply to this post by Nick G3RWF
Nick,
Sometimes the filters (particularly the narrower ones) do not respond well to the initial numbers in the manual because the filter center may be shifted a bit due to the particular set of matched crystals supplied. I don't think you have a problem. There is a solution, and that is called 'Spectrogram', which will provide a visual display of the filter shape and positioning on a computer screen. Download the last freeware version (5.17) of Spectrogram from www.n0ss.net and look at the instructions for using it on Tom's website or the Builder's Resource page of the Elecraft website. You could let the filter alignemnt wait until you have the rest of the K2 built and the KSB2 (if you added that) installed and then you can do a complete dial calibration and filter alignment. Instructions for doing that are on my website http://w3fpr.qrpradio.com 73, Don W3FPR > -----Original Message----- > > Thrilled to get my K2 working on 7 MHz receive but I seem to have > a problem with filter settings. > Everything has checked out according to the book - no problems at > all (even my home-wound coils seem to work!!) > I have set up the filters exactly according to pages 88 and 89. > On Filter 1 the rx sounds great - plenty of gain, clean signals. > On the other 3 filters it sounds like I am listening through a > dense fog - I can tell the bandwidth is far narrower than F1 but > signals are weak and it sounds as if the filters are overlapping > each other (if you know what I mean). I have checked settings > again and all look OK. Does anyone recognise this problem please? > I am reluctant to proceed until I have sorted it out. > 73 Nick G3RWF > No virus found in this outgoing message. Checked by AVG Free Edition. Version: 7.5.446 / Virus Database: 268.18.11/723 - Release Date: 3/15/2007 11:27 AM _______________________________________________ Elecraft mailing list Post to: [hidden email] You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com |
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In reply to this post by Craig Young
I'll be the third to chime in on how useful the spectrogram method of
aligning filters is. The first time around (without spectogram) I noticed similar results as you did, then I did the spectrogram alignment and it got *much* better, but it still wasn't right. Third time, it got even better. I'll be doing it again this weekend I think, it's somewhat of an art but it's also gratifying to see how much of a change it really can make. As Don said, you can do this anytime, no cause for concern at this point. 73, Jeff N6GQ On 3/16/07, [hidden email] <[hidden email]> wrote: > Nick, > > I wholeheartedly second this. I followed the manual and noticed the same thing you did. When I hooked up Spectrogram I could clearly see that the narrower filters were off center. I adjusted while watching the Spectrogram screen and things sound *much* better. > > Craig AC6NN > > > -------------- Original message ---------------------- > From: "Don Wilhelm" <[hidden email]> > > > > Nick, > > > > Sometimes the filters (particularly the narrower ones) do not respond well > > to the initial numbers in the manual because the filter center may be > > shifted a bit due to the particular set of matched crystals supplied. I > > don't think you have a problem. > > > > There is a solution, and that is called 'Spectrogram', which will provide a > > visual display of the filter shape and positioning on a computer screen. > > Download the last freeware version (5.17) of Spectrogram from www.n0ss.net > > and look at the instructions for using it on Tom's website or the Builder's > > Resource page of the Elecraft website. > > > > You could let the filter alignemnt wait until you have the rest of the K2 > > built and the KSB2 (if you added that) installed and then you can do a > > complete dial calibration and filter alignment. Instructions for doing that > > are on my website http://w3fpr.qrpradio.com > > > > 73, > > Don W3FPR > > > > > -----Original Message----- > > > > > > > > Thrilled to get my K2 working on 7 MHz receive but I seem to have > > > a problem with filter settings. > > > Everything has checked out according to the book - no problems at > > > all (even my home-wound coils seem to work!!) > > > I have set up the filters exactly according to pages 88 and 89. > > > On Filter 1 the rx sounds great - plenty of gain, clean signals. > > > On the other 3 filters it sounds like I am listening through a > > > dense fog - I can tell the bandwidth is far narrower than F1 but > > > signals are weak and it sounds as if the filters are overlapping > > > each other (if you know what I mean). I have checked settings > > > again and all look OK. Does anyone recognise this problem please? > > > I am reluctant to proceed until I have sorted it out. > > > 73 Nick G3RWF > > > > > -- > > No virus found in this outgoing message. > > Checked by AVG Free Edition. > > Version: 7.5.446 / Virus Database: 268.18.11/723 - Release Date: 3/15/2007 > > 11:27 AM > > > > _______________________________________________ > > Elecraft mailing list > > Post to: [hidden email] > > You must be a subscriber to post to the list. > > Subscriber Info (Addr. Change, sub, unsub etc.): > > http://mailman.qth.net/mailman/listinfo/elecraft > > > > Help: http://mailman.qth.net/subscribers.htm > > Elecraft web page: http://www.elecraft.com > > > _______________________________________________ > Elecraft mailing list > Post to: [hidden email] > You must be a subscriber to post to the list. > Subscriber Info (Addr. Change, sub, unsub etc.): > http://mailman.qth.net/mailman/listinfo/elecraft > > Help: http://mailman.qth.net/subscribers.htm > Elecraft web page: http://www.elecraft.com > Elecraft mailing list Post to: [hidden email] You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com |
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In reply to this post by Nick G3RWF
Nick
you did not say if you are receiving CW or SSB (i presume likely SSB since it is more BW dependant in fidelity). if you dont have the SSB adaptor installed, all the filters may be a little bit narrower than many HF rigs. when/if you add this board you will have an even higher fidelity SSB receive signal. if you get some decrease in intelligiability with narrower BW, no reason for alarm yet. I suggest also listening to both USB and LSB to see if you hear a difference. do download spectrogram and the application note at the Elecraft site (and/or use instructions at other's websites). it takes just an audio cable from your K2 audion output into your PC soundcard. software settings may take some patience to get them set up, but you will be rewarded by 'seeing' your filters. and for fun you will likely check out your other rigs! enjoy your K2 build! 73, curt ----- Original Message ---- From: Nick Henwood <[hidden email]> To: [hidden email] Sent: Friday, March 16, 2007 6:20:04 AM Subject: [Elecraft] K2 Filter settings Thrilled to get my K2 working on 7 MHz receive but I seem to have a problem with filter settings. Everything has checked out according to the book - no problems at all (even my home-wound coils seem to work!!) I have set up the filters exactly according to pages 88 and 89. On Filter 1 the rx sounds great - plenty of gain, clean signals. On the other 3 filters it sounds like I am listening through a dense fog - I can tell the bandwidth is far narrower than F1 but signals are weak and it sounds as if the filters are overlapping each other (if you know what I mean). I have checked settings again and all look OK. Does anyone recognise this problem please? I am reluctant to proceed until I have sorted it out. 73 Nick G3RWF _______________________________________________ Elecraft mailing list Post to: [hidden email] You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com ____________________________________________________________________________________ Now that's room service! Choose from over 150,000 hotels in 45,000 destinations on Yahoo! Travel to find your fit. http://farechase.yahoo.com/promo-generic-14795097 _______________________________________________ Elecraft mailing list Post to: [hidden email] You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com |
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