K2 calibration questions
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Hi
Do people still ask about the venerable K2 on this group? hi my K2 serial # 5312 : I built it 9 yrs ago now. SO, I went back and (nervously) re-opened my K2 and re-did some of the calibration routines. The 4 Mhz calibration would not zero beat at 4.0000 Mhz but at 3999.8 The PLL ref Bosc range was OK BFO test was OK The CAL FCTR procedure would not allow zero beat on WWV 10 Mhz sig. Readings were zero beat at 10000.19. Needed to get FCTR to 14911.82 could only get to 14912.08 a diff of 1.74 Re-did PLL as required. No probs there. I am aware of the limitations of freq calib with the K2 when in the Hz range However I did not used to have this much of a problem. I am probably missing something obvious. That’s where you guys come in! Thanks John AB8O ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to [hidden email] |
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The following app nite from Elecraft describes a great way to calibrate the dial on your K2:http://www.elecraft.com/Apps/K2%20C22%20Adjust%20App%20Note.pdf
After setting C22 and running CAL PLL, don't forget to also run CAL FIL and update the BFO setting for each filter (even if you just increase it by a small amount, then go back and change it back to the original value) -- you need to make a change in order to force the firmware to take account of the calibration adjustments in the previous steps. There is a good article on K2 dial calibration on Don W3FPR's website:http://w3fpr.com/ 73, Matt VK2RQ On Sun, Aug 23, 2015 at 11:02 AM -0700, "John Wiener" <[hidden email]> wrote: Hi Do people still ask about the venerable K2 on this group? hi my K2 serial # 5312 : I built it 9 yrs ago now. SO, I went back and (nervously) re-opened my K2 and re-did some of the calibration routines. The 4 Mhz calibration would not zero beat at 4.0000 Mhz but at 3999.8 The PLL ref Bosc range was OK BFO test was OK The CAL FCTR procedure would not allow zero beat on WWV 10 Mhz sig. Readings were zero beat at 10000.19. Needed to get FCTR to 14911.82 could only get to 14912.08 a diff of 1.74 Re-did PLL as required. No probs there. I am aware of the limitations of freq calib with the K2 when in the Hz range However I did not used to have this much of a problem. I am probably missing something obvious. That’s where you guys come in! Thanks John AB8O ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to [hidden email] ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to [hidden email] |
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In reply to this post by John Wiener
John,
Certainly, this is a valid reflector for any Elecraft product. Don't worry about exactly 4.000 MHz on that reference oscillator. It is only important that it be "right on" just before running CAL PLL followed by CAL FIL - and the frequency may not be exactly 4.000 MHz when set properly anyway. That check in the manual was intended not as a calibration point, but only as a check to see if the oscillator was actually in close range of where it needs to be. When not running CAL PLL and CAL FIL, the K2 does not depend on that oscillator at all, it uses the data stored in memory during those routines to know what frequency to display. If you really want to fine tune the K2 dial calibration, go to the article on my website www.w3fpr.com and follow the procedure there. You will need to use Spectrogram or other audio spectrum analyzer to correctly tune in WWV and also to judge the width and placement of your IF filters. If you need spectrogram, look for the links near the bottom of my Home webpage. Those are links local to my website and those copies have been virus scanned many times and are known to be 'clean'. Be aware that due to limitations in the BFO DAC, you may find up to a 20Hz error in the final dial calibration results. That was quite tolerable until recently when new data modes (such as JT65) were developed requiring greater frequency accuracy. The K2 may not be suitable for those modes for that reason. 73, Don W3FPR On 8/23/2015 2:02 PM, John Wiener wrote: > Hi > Do people still ask about the venerable K2 on this group? hi > > my K2 serial # 5312 : > > I built it 9 yrs ago now. > > SO, I went back and (nervously) re-opened my K2 and re-did some of the calibration routines. > > The 4 Mhz calibration would not zero beat at 4.0000 Mhz but at 3999.8 > > The PLL ref Bosc range was OK > > BFO test was OK > > The CAL FCTR procedure would not allow zero beat on WWV 10 Mhz sig. Readings were zero beat at 10000.19. Needed to get FCTR to 14911.82 could only get to 14912.08 a diff of 1.74 > > Re-did PLL as required. No probs there. > > I am aware of the limitations of freq calib with the K2 when in the Hz range However I did not used to have this much of a problem. > > I am probably missing something obvious. > > That’s where you guys come in! > > ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to [hidden email] |
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Don,
I use my K2 on JT65 all the time, in fact I hardly ever even pick up the microphone anymore. I find that I need it to warm up for about 15 minutes before the VFO stops slowly drifting. However, even cold, the short term drift on the K2 is slow enough to run JT65 without issues (at least mine is!). Thanks for all you contribute to this forum! 73, David AJ4TF High Point, NC K2 # 7006 |
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David,
I concede on that, and yes, warmup drift is normal. I erred in using JT65 as the example, it just requires frequency stability (which the K2 can do after warmup). What I really intended are a few modern data modes that I understand must be 'netted' to a specific frequency, down to the single digit Hz. The 20 Hz DAC steps in the K2 BFO may not allow that. 73, Don W3FPR On 8/23/2015 5:53 PM, aj4tf wrote: > Don, > I use my K2 on JT65 all the time, in fact I hardly ever even pick up the > microphone anymore. I find that I need it to warm up for about 15 minutes > before the VFO stops slowly drifting. However, even cold, the short term > drift on the K2 is slow enough to run JT65 without issues (at least mine > is!). > > ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to [hidden email] |
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