K2 Part II Alignment Probs
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I'm struggling with the Part II alignment of my new K2 (s/n 5430) and
looking for suggestions. BFO Test -- The BFO high freq is a little low, but the overall range is acceptable. This is probably due to the fact that I don't have a way to set C22 for 4.000MHz. CAL FIL -- when I use the numbers from page 89 of the manual and then listen to the 7040 signal from an XG2 I am clearly listening on the 'wrong sideband'. When I use the values I received from Gary I can hear the carrier on 'both sidebands'. IF Alignment -- the S/N gets better and better as I screw in the L34 slug. It bottoms out before I reach a peak. Question: Are all these problems related? I could make an unknown change to C22 in an attempt to get the displayed value to look correct -- but does that really make any difference? I could use spectrogram to adjust the filters, but my original thought was to simply use the supplied values until this rig is completely built up and then go back an do the fine tuning. If the CAL FIL and the IF issue are not related I could change the value of C182 to 150pf and try again on the IF alignment. My next step will be to once again check all values of components in the crystal filter, if amp and product detector and the soldering but I really don't think anything will have changed from my check last night. Ideas? Suggestions? Are these issues related? Mark AD5SS _______________________________________________ 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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Like you, I used the settings from the manual for CAL FIL and they
worked OK. Several weeks after completing the rig I went back and optimized them with Spectrogram. I used a 2nd rig to adjust C22 to get the osc. to 4 MHz. Just for fun, go back and give C22 a tweak and see if the symptoms change. You have nothing to lose as you can always just put it back in it's centered position. - Keith - -----Original Message----- Mark Bayern CAL FIL -- when I use the numbers from page 89 of the manual and then listen to the 7040 signal from an XG2 I am clearly listening on the 'wrong sideband'. When I use the values I received from Gary I can hear the carrier on 'both sidebands'. _______________________________________________ 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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On 5/4/06, Darwin, Keith <[hidden email]> wrote:
> Like you, I used the settings from the manual for CAL FIL and they > worked OK. Several weeks after completing the rig I went back and > optimized them with Spectrogram. Not quite -- when I use the manual's values I'm on the wrong side of the passband. _______________________________________________ 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 Mark Bayern-2
Let me try that again :-). Like you I used the values from the manual. Unlike your case however, I got good results. Just wanted to let you know using values straight out of the manual can get you pretty close. Something is not quite right with your rig ... ... But you already knew that :-) - Keith - -----Original Message----- On 5/4/06, Darwin, Keith <[hidden email]> wrote: > Like you, I used the settings from the manual for CAL FIL and they > worked OK. Several weeks after completing the rig I went back and > optimized them with Spectrogram. Not quite -- when I use the manual's values I'm on the wrong side of the passband. _______________________________________________ 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 Mark Bayern-2
Mark,
Can you be specific about how you are determining that the BFOs are on the wrong side of the carrier? Using 40 meters, tune in a signal, then tune the pitch of the signal to a lower tone, observing which way you turn the VFO dial - if you have LSB or CW selected, the pitch should become lower as you tune lower in frequency - USB and CWr will be the reverse. If you indeed do have inverted sidebands, then re-check the BFO range test and let us know what the high and low BFO frequencies are. and let us know the number (x.x) that was marked on the envelope your crystals were packaged in. Also, do you have the KSB2 installed yet or not? 73, Don W3FPR > -----Original Message----- > From: [hidden email] > [mailto:[hidden email]]On Behalf Of Mark Bayern > Sent: Thursday, May 04, 2006 2:58 PM > To: Darwin, Keith > Cc: [hidden email] > Subject: Re: [Elecraft] K2 Part II Alignment Probs > > > On 5/4/06, Darwin, Keith <[hidden email]> wrote: > > Like you, I used the settings from the manual for CAL FIL and they > > worked OK. Several weeks after completing the rig I went back and > > optimized them with Spectrogram. > > Not quite -- when I use the manual's values I'm on the wrong side of > the passband. > _______________________________________________ > 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 > > > -- > No virus found in this incoming message. > Checked by AVG Free Edition. > Version: 7.1.392 / Virus Database: 268.5.3/331 - Release Date: 5/3/2006 > > _______________________________________________ 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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> Can you be specific about how you are determining that the BFOs are on the
> wrong side of the carrier? I'm listening to the 7.040MHz generated by an XG2. When I have CW (not R) selected the pitch goes down as I turn up in frequency. I'll give you the BFO high & low freqs and the marking on the crystal envelope when I get home in an hour or so. No KSB2 yet. I'll add it after the basic rig works. Thanks for the response. Mark > > Using 40 meters, tune in a signal, then tune the pitch of the signal to a > lower tone, observing which way you turn the VFO dial - if you have LSB or > CW selected, the pitch should become lower as you tune lower in frequency - > USB and CWr will be the reverse. > > If you indeed do have inverted sidebands, then re-check the BFO range test > and let us know what the high and low BFO frequencies are. and let us know > the number (x.x) that was marked on the envelope your crystals were packaged > in. > > Also, do you have the KSB2 installed yet or not? > > 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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Mark, while you have the probe in TP2, also check the BFO frequencies for CW
FL1 thru FL4 and include them with the info you send. 73, Don W3FPR > -----Original Message----- > From: [hidden email] > [mailto:[hidden email]]On Behalf Of Mark Bayern > Sent: Thursday, May 04, 2006 6:07 PM > To: [hidden email] > Cc: [hidden email] > Subject: Re: [Elecraft] K2 Part II Alignment Probs > > > > Can you be specific about how you are determining that the BFOs > are on the > > wrong side of the carrier? > > I'm listening to the 7.040MHz generated by an XG2. When I have CW > (not R) selected the pitch goes down as I turn up in frequency. > > I'll give you the BFO high & low freqs and the marking on the crystal > envelope when I get home in an hour or so. No KSB2 yet. I'll add it > after the basic rig works. > > Thanks for the response. > > Mark > > > > > > Using 40 meters, tune in a signal, then tune the pitch of the > signal to a > > lower tone, observing which way you turn the VFO dial - if you > have LSB or > > CW selected, the pitch should become lower as you tune lower in > frequency - > > USB and CWr will be the reverse. > > > > If you indeed do have inverted sidebands, then re-check the BFO > range test > > and let us know what the high and low BFO frequencies are. and > let us know > > the number (x.x) that was marked on the envelope your crystals > were packaged > > in. > > > > Also, do you have the KSB2 installed yet or not? > > > > > _______________________________________________ > 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 > > > -- > No virus found in this incoming message. > Checked by AVG Free Edition. > Version: 7.1.392 / Virus Database: 268.5.3/331 - Release Date: 5/3/2006 > > _______________________________________________ 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 Don Wilhelm-3
> If you indeed do have inverted sidebands, then re-check the BFO range test
> and let us know what the high and low BFO frequencies are. and let us know > the number (x.x) that was marked on the envelope your crystals were packaged > in. Doing the BFO Test from page 62: BFO high freq 4916.20 BFO low freq 4911.09 BFO freqs measured at TP2. band+ band- FL1 4913.61 4916.21 4911.01 FL2 4913.22 4916.20 4911.09 FL3 4913.22 4916.20 4911.09 FL4 4913.11 4916.20 4911.09 The first column of freqs is the BFO frequency before pressing the B+ or the B- button. Note that C22 (the 4.000MHz calib) is not calibrated at this time. The crystal envelope had a 3.7 (three point seven) written on its front. > > Also, do you have the KSB2 installed yet or not? KSB2 is not yet installed. Thanks! _______________________________________________ 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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I should have reiterated that the IF tuning slug bottoms out as the
snr is improving -- is something wrong with the IF frequency or is this just a side effect of the filter problem? Mark On 5/4/06, Mark Bayern <[hidden email]> wrote: > > If you indeed do have inverted sidebands, then re-check the BFO range test > > and let us know what the high and low BFO frequencies are. and let us know > > the number (x.x) that was marked on the envelope your crystals were packaged > > in. > > Doing the BFO Test from page 62: > > BFO high freq 4916.20 > BFO low freq 4911.09 > > > BFO freqs measured at TP2. > band+ band- > FL1 4913.61 4916.21 4911.01 > FL2 4913.22 4916.20 4911.09 > FL3 4913.22 4916.20 4911.09 > FL4 4913.11 4916.20 4911.09 > > The first column of freqs is the BFO frequency before pressing the B+ > or the B- button. Note that C22 (the 4.000MHz calib) is not calibrated > at this time. > > The crystal envelope had a 3.7 (three point seven) written on its front. > > > > > > Also, do you have the KSB2 installed yet or not? > > KSB2 is not yet installed. > > Thanks! > 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 Mark Bayern-2
Mark,
The BFO frequencies look OK, and the 3.7 marking on your crystals say that the IF frequency should be close to the center of 'normal' (=usual), so if you have inverted sidebands, we need to look for something else awry. Tune to 7000 and put the counter probe into TP1 and tell me what the frequency reading is there (in CAL FCTR mode) - 11915 kHz is expected. Sideband inversion can only happen if the mixer (or product detector) frequencies are incorrect. If your TP1 and TP2 frequencies are correct and you still are receiving on the incorrect sideband, that would be a mystery to me (the math says it has to be correct), so we would have to look at your test setup - is it possible that you are driving a very strong signal into the K2 and you are actually hearing both sidebands? If you hear both, then either your filter is not working properly or your signal input is so strong it is overloading the receiver, or maybe something else, but this situation is not normal. 73, Don W3FPR > -----Original Message----- > > > If you indeed do have inverted sidebands, then re-check the BFO > range test > > and let us know what the high and low BFO frequencies are. and > let us know > > the number (x.x) that was marked on the envelope your crystals > were packaged > > in. > > Doing the BFO Test from page 62: > > BFO high freq 4916.20 > BFO low freq 4911.09 > > > BFO freqs measured at TP2. > band+ band- > FL1 4913.61 4916.21 4911.01 > FL2 4913.22 4916.20 4911.09 > FL3 4913.22 4916.20 4911.09 > FL4 4913.11 4916.20 4911.09 > > The first column of freqs is the BFO frequency before pressing the B+ > or the B- button. Note that C22 (the 4.000MHz calib) is not calibrated > at this time. > > The crystal envelope had a 3.7 (three point seven) written on its front. > > _______________________________________________ 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 Mark Bayern-2
Mark,
Yes, that is an important piece of information. Move the L34 tuning slug up to near the top - 1 to 1 1/2 turns in from the top and leave it there for the time being - then re-check your sideband inversion problem. 73, Don W3FPR > -----Original Message----- > > I should have reiterated that the IF tuning slug bottoms out as the > snr is improving -- is something wrong with the IF frequency or is > this just a side effect of the filter problem? > > Mark > _______________________________________________ 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 Don Wilhelm-3
> Tune to 7000 and put the counter probe into TP1 and tell me what the
> frequency reading is there (in CAL FCTR mode) - 11915 kHz is expected. 7000.00MHz CW, St P of 0.60 at TP1: 11914.18 TP3: 12094.20 TP2: 4913.60 If my math is correct, mixing 7000.00 and 11914.18 should have an output at 4914.18. Is this the expected value? Is it on the 'correct' side of the IF filter? (Keep mind that my C22 has not been set, its just at the midpoint.) > ... so we would have to look at your > test setup - is it possible that you are driving a very strong signal into > the K2 and you are actually hearing both sidebands? I hear the incorrect sideband when using the filter settings shown on page 89 of the Rev F manual. I hear both sidebands when using the filter settings that Gary Surrency sent me. Yes I was using a strong signal -- the high output from an XG2 with the preamp still ON. I have now switched to the lower output on the XG2 and turned the preamp off. Still hearing the wrong sideband. I guess a wrong IF frequency would explain the problem with tuning the IF can, but I'm still baffled about how the IF frequency can be wrong. By the way, I can match the XG2 to the spot tone (do we still call this zero-beating?) at 7037.60 on the display, but the tone goes down when I turn the freq dial up towards 7040. _______________________________________________ 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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Mark,
Yes, your math is correct, and since your BFO is at a lower frequency than the IF, that should give you LSB output - something strange is going on here. Let's take this off-reflector after this note, because we may have to exchange a bit of detail information. It may be of interest to some, but the specifics are not common for most cases, and I don't want to cause boredom for other builders for your specific problem - you can report the results to the list after we figure things out. The VCO frequency is within the realm of reason, we do not need to look at that further. Did you move the slug of L34 up near the top of the can? If you would remove the [Elecraft} from the subject in your reply, that will make your reply more obvious to me (it will go to my inbox rather than the Elecraft folder - which I peruse more quickly than my inbox). Go to Tom Hammond's website www.n0ss.net and download Spectrogram (it will be near the end of the page). I will help you get it setup if necessary, but I need to know how your filter bandpass looks on the Spectrogram display before I can draw any conclusions or offer any suggestions. My initial guess is that your actual filter bandwidth is much wider than expected (indicating a problem with the filter itself), and your passband may be straddling the zero frequency point - but all that remains to be seen. 73, Don W3FPR > -----Original Message----- > > > Tune to 7000 and put the counter probe into TP1 and tell me what the > > frequency reading is there (in CAL FCTR mode) - 11915 kHz is expected. > > 7000.00MHz CW, St P of 0.60 > > at TP1: 11914.18 > TP3: 12094.20 > TP2: 4913.60 > > If my math is correct, mixing 7000.00 and 11914.18 should have an > output at 4914.18. Is this the expected value? Is it on the 'correct' > side of the IF filter? (Keep mind that my C22 has not been set, its > just at the midpoint.) > > > ... so we would have to look at your > > test setup - is it possible that you are driving a very strong > signal into > > the K2 and you are actually hearing both sidebands? > > I hear the incorrect sideband when using the filter settings shown on > page 89 of the Rev F manual. I hear both sidebands when using the > filter settings that Gary Surrency sent me. > > Yes I was using a strong signal -- the high output from an XG2 with > the preamp still ON. I have now switched to the lower output on the > XG2 and turned the preamp off. Still hearing the wrong sideband. > > I guess a wrong IF frequency would explain the problem with tuning the > IF can, but I'm still baffled about how the IF frequency can be wrong. > By the way, I can match the XG2 to the spot tone (do we still call > this zero-beating?) at 7037.60 on the display, but the tone goes down > when I turn the freq dial up towards 7040. > > > -- > No virus found in this incoming message. > Checked by AVG Free Edition. > Version: 7.1.392 / Virus Database: 268.5.3/331 - Release Date: 5/3/2006 > > _______________________________________________ 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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