[Elecraft] beat freq method

[FredJensen]

A couple of hints:

1.  You must be in CW mode with three digits showing to the right of the 
decimal point in the freq display.  It helps a lot to narrow the WIDTH 
to 200 Hz or even less.  You won't hear [or at least be able to 
understand] the voice announcements, and the second "ticks" will sound 
strange.  Set VFO A to the exact WWV frequency [e.g. 15.000.000] in the 
display.  I suggest you start this whole procedure during one of the 
minutes when WWV does *not* have the tone on, assuring you are listening 
to the CW beat note from the carrier.  If you are close and your BW is 
less than 200 Hz, you may not hear the tone when it comes back on.

2.  You "turn on the sidetone" by doing a HOLD on the MON knob ["CMP 
PWR"]  You'll hear the sidetone at whatever you have the PITCH set to.

3.  The knob now adjusts the level of the sidetone in your phones.  For 
this to work, that level needs to be approximately equal to the level of 
WWV in your phones.  You can equalize them with either the MON knob or 
the AF gain, or both.

4.  When you're in CONFIG:REF CAL, as you tune VFO A, the pitch of WWV 
will vary, the sidetone will remain constant.  Your goal is to get WWV 
exactly the same pitch as your continuous sidetone.  If it is a bit off, 
you may actually hear the very low beat note.  If it is close, you'll 
hear the combined audio signals fading up and down rather than a "beat 
note."  That fading *is* the beat note but it's too low a frequency to 
hear it as a tone.

5.  As you close in on a match between WWV and your sidetone, the in and 
out fading will slow down, almost stop, and then begin to speed up again 
as you move past zero beat.  It takes a bit as you are right at the zero 
beat point to find the absolute slowest in and out fading.

6.  Although you can't tell when your K3 is in FINE tuning rate, the 
frequency is moving step-wise when you tune.  You'll find as you 
approach zero beat, the in and out fading will slow, and then speed up a 
tiny bit, most likely never really stopping.  That's because one DDS 
tuning step was just a tad below exact, and the next DDS step was just a 
tad above exact.  Pick the step with the slowest rate.  If you actually 
get the in and out fading to stop, you should buy a Power Ball ticket 
immediately :-)

7.  The fading you hear is actually the individual cycles of the "beat 
note."  When you're very close, you can count the number of peaks in 
some period, say 30 sec, and divide that count by the length of the 
period you used [in seconds].  The quotient is the beat note frequency.  
Mine is about 0.1 Hz which translates to 0.1 Hz frequency error when 
receiving.

8.  Use the highest frequency WWV you can hear.  Even without the KBPF3, 
I could hear 2.5 [at night], 5 [most of the time], and 15 and 20 during 
the day.

For the record, I've done this several times figuring the K3 will 
drift.  So far, I cannot detect any drift and my REF CAL frequency 
hasn't changed since I first calibrated.  Be sure your K3 FP temp has 
stabilized before starting [tap DISP and use VFO B to find "FP" followed 
by a temp].

OK, I lied, that's 8 hints and one hint-let.

73,

Fred K6DGW
Auburn CA

On 3/28/2011 5:45 PM, Don Wilhelm wrote:
> Tune in WWV - make certain you are tuned to the carrier - use CW mode
> (you will not be able to understand the voice in CW mode), and adjust
> the VFO so the carrier is quite near the audio pitch of your sidetone.
> Now turn on the sidetone, and adjust the AF gain so the sidetone level