Alignment and Test Part II
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While doing the 4 MHz Oscillator calibration, CAL FCTR shows 12100.10 which
seem nominal. But adjusting C22 doesn't allow me to change it very much at all, maybe a few hundred Hz. It this normal? Thanks for any help. Brian Denley http://home.comcast.net/~b.denley/index.html ______________________________________________________________ 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 |
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Brian,
That is entirely normal. Which one of the 3 methods mentioned are you using to calibrate the 4 MHz reference? 1) Measure the TP3 frequency with an accurate external counter - adjust C22 until the K2 display matches the external counter. 2) Listen to the 4 MHz signal with another receiver - tune C22 until right on 4 MHz. 3) Just set the C22 trimmer slot to the midpoint. Actually a better method (greater accuracy) exists - wait until you have completed the K2 and you can receive 10 MHz ((or 15 MHz) WWV, then use the N6KR method. You can find the "How-To" on my website www.w3fpr.com article on K2 Dial Calibration. 73, Don W3FPR Brian Denley wrote: > While doing the 4 MHz Oscillator calibration, CAL FCTR shows 12100.10 which > seem nominal. But adjusting C22 doesn't allow me to change it very much at > all, maybe a few hundred Hz. It this normal? > Thanks for any help. > > ______________________________________________________________ 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 |
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Don:
I used a separate frequency counter but I did struggle with finding a suitable probe. Direct connection seemed to load down the circuit and change the frquency slightly. I ended up using a 10X scope probe. That seemed to work OK. I have read you writeup of the N6KR procedure and I will give bit a try and report back. Just in case a spent some time calibrating a couple of my receivers within a few Hz in case I needed to use that method. It's been a while since my Tek counter has been calibrated. Brian http://home.comcast.net/~b.denley/index.html ----- Original Message ----- From: "Don Wilhelm" <[hidden email]> To: "Brian Denley" <[hidden email]> Cc: "Elecraft Reflector" <[hidden email]> Sent: Sunday, August 01, 2010 9:37 AM Subject: Re: [Elecraft] Alignment and Test Part II > Brian, > > That is entirely normal. Which one of the 3 methods mentioned are you > using to calibrate the 4 MHz reference? > 1) Measure the TP3 frequency with an accurate external counter - adjust > C22 until the K2 display matches the external counter. > 2) Listen to the 4 MHz signal with another receiver - tune C22 until right > on 4 MHz. > 3) Just set the C22 trimmer slot to the midpoint. > > Actually a better method (greater accuracy) exists - wait until you have > completed the K2 and you can receive 10 MHz ((or 15 MHz) WWV, then use the > N6KR method. You can find the "How-To" on my website www.w3fpr.com > article on K2 Dial Calibration. > > 73, > Don W3FPR > > Brian Denley wrote: >> While doing the 4 MHz Oscillator calibration, CAL FCTR shows 12100.10 >> which seem nominal. But adjusting C22 doesn't allow me to change it very >> much at all, maybe a few hundred Hz. It this normal? >> Thanks for any help. >> >> ______________________________________________________________ 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 |
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Brian,
Yes, a 10X probe on the counter may be necessary to prevent loading - that depends on the counter and its input impedance.. If you know your counter is accurate, that will got things right on frequency, but if you have doubts about the accuracy of your counter, use the N6KR method which relies only on the received 'Standard Frequency' signal. All other errors are compensated when using that method - it will produce the best dial calibration accuracy that I am aware of. For those who have questions about how to do the :"N6KR" method, I suggest you look at my website article on K3 Dial Calibration www.w3fpr.com or search the Elecraft reflector for Wayne's original posting of that method. All I can say is that it works very well, and I use it on a daily basis when aligning K2s. 73, Don W3FPR Brian Denley wrote: > Don: > I used a separate frequency counter but I did struggle with finding a > suitable probe. Direct connection seemed to load down the circuit and > change the frquency slightly. I ended up using a 10X scope probe. That > seemed to work OK. I have read you writeup of the N6KR procedure and I will > give bit a try and report back. Just in case a spent some time calibrating > a couple of my receivers within a few Hz in case I needed to use that > method. It's been a while since my Tek counter has been calibrated. > Brian > > 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 |
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