K2 C22 Adjustment Method Question

[Jim KO5V]

Good afternoon,

A couple of weeks ago, I pulled # 7225 out of its long hibernation and finished it Friday night. It lives, and it has passed all of its tests! The only problem I had was during the VCO test. It was showing 0000.00, and after about 4 hours, I found that C68 was not a 10pf cap - it was a 1pf cap labelled "1D" - which looked a lot like a "10" to me. I built and added the SSB adapter yesterday, and I plan to set up the mic this afternoon. So far, I've heard signals on 80M-17M, and it sounds pretty good, although I still need to properly set up the filters with Spectrogram.

This is my third K2, I stupidly sold #1, and #2 was killed because some idiot forgot to unhook the antenna a couple of days before an electrical storm. Anyway, I really enjoy building these kits!

For adjusting C22, I don't have a receiver that I trust to be accurate @ 4MHz. Looking at Don's page, I decided to use Wayne's method of moving the internal probe from TP1 to TP2 after zero-beating WWV @ 10MHz. The signal was weak, but in cw mode, I could hear the carrier (I hope that's what it was...). My K2's tone is set to 600hz, so using "Spot", I zero-beat WWV's carrier in cw and cwR, which seemed to occur within 10Hz of each other. I then switched to usb and adjusted C22 so the readings at TP1 and TP2 were within +/- 20Hz (best I could do). I ran CAL PLL, and CAL filter on 40M. WWV seems to be almost right on at 10000.01MHz. However, when I switch to 20Mhz, and use then same method to zero-beat with Spot and cw and cwR, the reading is 19.999.92MHz.

Is this a normal thing, or is my understanding of the method flawed? I would bet on the latter...

Thanks in advance.

73, Jim KO5V
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[Don Wilhelm]

Jim,

You really need to use an AM station like WWV so you do not encounter
the receive offset problem.  Using Spectrogram to receive WWV can help
you see the transmitted tone.  There is a distinctive tone for one
second at the start of each minute, even if you cannot see the 500 and
600 Hz tones that are transmitted.  Try both 15MHz WWV which can usually
be heard during daylight hours and 10 MHz WWV which is usually stronger
at night.

If you can only receive a carrier, you can use alternate method of
tuning in WWV.  That is detailed in the link on my website.
That link is by Vicenç Llario, EA3ADV.  That link was written for
receiving RWM at 9996.00 kHz which transmits only a carrier, but can
also be applied to the carrier of WWV.  Note that it is more complex
than using the WWV tones.

73,
Don W3FPR

On 10/14/2018 3:19 PM, Jim KO5V wrote:
> Good afternoon,
>
> A couple of weeks ago, I pulled # 7225 out of its long hibernation and finished it Friday night. It lives, and it has passed all of its tests! The only problem I had was during the VCO test. It was showing 0000.00, and after about 4 hours, I found that C68 was not a 10pf cap - it was a 1pf cap labelled "1D" - which looked a lot like a "10" to me. I built and added the SSB adapter yesterday, and I plan to set up the mic this afternoon. So far, I've heard signals on 80M-17M, and it sounds pretty good, although I still need to properly set up the filters with Spectrogram.
>
> This is my third K2, I stupidly sold #1, and #2 was killed because some idiot forgot to unhook the antenna a couple of days before an electrical storm. Anyway, I really enjoy building these kits!
>
> For adjusting C22, I don't have a receiver that I trust to be accurate @ 4MHz. Looking at Don's page, I decided to use Wayne's method of moving the internal probe from TP1 to TP2 after zero-beating WWV @ 10MHz. The signal was weak, but in cw mode, I could hear the carrier (I hope that's what it was...). My K2's tone is set to 600hz, so using "Spot", I zero-beat WWV's carrier in cw and cwR, which seemed to occur within 10Hz of each other. I then switched to usb and adjusted C22 so the readings at TP1 and TP2 were within +/- 20Hz (best I could do). I ran CAL PLL, and CAL filter on 40M. WWV seems to be almost right on at 10000.01MHz. However, when I switch to 20Mhz, and use then same method to zero-beat with Spot and cw and cwR, the reading is 19.999.92MHz.
>
> Is this a normal thing, or is my understanding of the method flawed? I would bet on the latter...
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Please help support this email list: http://www.qsl.net/donate.html
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