[Elecraft] K2 BFO

[Hisashi T Fujinaka]

Or you can use a second AM receiver and zero beat the tones. You can get
it very close that way.

On Mon, 28 Jun 2021, Don Wilhelm wrote:

> Jerry,
>
> Read the article on my website.  Just adjusting C22 is not enough for a 
> complete job of dial calibration.
> That oscillator is the clock for the MCU.  The dial calibration data is 
> stored in EEPROM and is what is used to display the dial frequency.  The 
> EEPROM is loaded by running the CAL PLL menu routine with the counter 
> probe in TP1.
> Yes, C22 must be adjusted just before running CAL PLL or CAL BFO.
>
> I use WWV which transmits 500 or 600 Hz tones on alternate minutes. 
> Using SSB, align those tones with the 500 and 600 Hz markers on your 
> audio spectrum analyzer to assure that you are tuned correctly.
>
> Once you get the KSB2 option installed, you can enter the BFO 
> frequencies suggested in the manual and then proceed to do a more 
> precise dial and BFO calibration.
>
> The DAC steps for the BFO limits the precision that you can achieve, but 
> 10 to 20 Hz is achievable.
>
> 73,
> Don W3FPR
>
> On 6/28/2021 2:16 PM, jerry wrote:
>> Hi Don,
>>
>>    One of the first things I did after getting this rig in the mail, 
>> was to verify that it received WWV at the proper frequency - and that 
>> USB sounded like LSB.  That reassured me
>> that the dial was accurate enough to keep me inside the ham bands.
>>
>>    People often instruct one to "zero beat" WWV.  I fail to see how 
>> this can be done with an SSB receiver with a properly set BFO, since 
>> the carrier is then outside of the filter bandpass.   Also, except 
>> during the announcement period, WWV is actually transmitting multiple 
>> "carrier" frequencies at the same time.
>>
>>    Not going to mess with SSB a lot at this time because I have the 
>> SSB adapter on order, and I'd have to do it all again anyway after 
>> receiving that.
>>
>>    I just calibrated the counter with the GPSDO.  It was showing 
>> 9.....96 ( forget how many digits :).  A quick tweak of the trimmer 
>> cap got it to 10.0000 ( however many zeros ).
>>
>>    This is just a temporary bodge, because I also have a TCXO on 
>> order, will have to do that again too.
>>
>>                      - Jerry KF6VB
>>
>>
>>
>>
>>
>>
>> On 2021-06-28 10:39, Don Wilhelm wrote:
>>> Jerry,
>>>
>>> That GPSDO will be good for setting the dial calibration, but WWV is
>>> better since it transmits AM at a fixed frequency.
>>> Instructions for doing a good dial calibration are on my website
>>> www.w3fpr.com.  It explains the entire procedure.
>>> Use SSB when doing the dial calibration because there is an offset if
>>> you try to use CW - no offset with SSB.
>>>
>>> 73,
>>> Don W3FPR
>>>
>
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:Elecraft at mailman.qth.net
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html
> Message delivered to htodd at twofifty.com

-- 
Hisashi T Fujinaka - htodd at twofifty.com
BSEE + BSChem + BAEnglish + MSCS + $2.50 = coffee