This is not meant to in any way infer that any one is incompetent. Only that with the complexity of today's equipment you almost always need a service manual to make any adjustments.
    This information can be used to check and or calibrate your HF rig frequency accuracy.

Both WWV and WWVH broadcast standard frequency audio tones that alternate during most minutes of the hour. Most minutes feature a 500 or 600 Hz audio tone. However, a 440 Hz tone is broadcast once per hour, and some minutes do not include any audio tones at all.

The 440-Hz tone (the musical note A above middle C) is broadcast once each hour, during minute 2 on WWV, and minute 1 on WWVH. In addition to being a musical standard, the 440-Hz tone provides an hourly marker for chart recorders and other automated devices. The 440-Hz tone is omitted, however, during the first hour of each UTC day.

 The schedule for the audio tones is listed in the table below, with the minutes labeled from 0 to 59.
 

Audio Tone	Station	Minutes
500 Hz	WWV	4, 6, 12, 16, 20, 22, 24, 26, 28, 32, 34, 36, 38, 40, 42, 52, 54, 56, 58
600 Hz	WWV	1, 3, 5, 7, 11, 13, 17, 19, 21, 23, 25, 27, 31,33, 35, 37, 39, 41, 53, 55, 57
440 Hz	WWV	2
None	WWV	8 to 10, 14 to 15, 18, 29 to 30, 43 to 51, 59

 
 

NOTE: This procedure may not work on all rigs. I know it works on the icom 706 and 746 other than that I can't say.
To perform this procedure you will need:
(1) a HF radio capable of receiving the WWV broadcast in SSB mode
(2) a computer with sound card
(3) the program spectra gram
(4) a patch cord from the radio audio out to the computer sound card line input
(5) some time
 gram517.zip   A free version of spectra gram program you will need for this procedure
NOTE: the computer and program are not required, it only makes the process easier.

This is NOT a sigma 4 calibration so don't expect that accuracy, you can however achieve enough accuracy that most people can't hear the error in frequency.
Use the highest WWV frequency that you can reliably receive, 20 MHz as the first choice then 2.5 MHz as a last choice. If you have one of the newer rigs that cover six meters and above, I would not use any WWV frequency below 10 MHz. The reason for this is below 10 MHz the resolution of your measurement is just to low, one part in 20 million is much finer than one part in 2.5 million. Say your target frequency is 60 MHz, and your local master oscillator in your rig is 60 MHz then you have a 1:1 ratio, therefore 60/2.5=24 cycles and 60/10=6 cycles as you can see by using 10 MHz you can achieve a reasonable accuracy that you cannot get at 2.5 MHz. This is not to say you will achieve this accuracy but it is possible. Another way to look at this is, if you are off by 20 Hz at 10 MHz then you will be off by 100 Hz at 50 MHz ( 50 MHz/10 MHz = a 5:1 ratio ) therefore 20 * 5  = 100 Hz. Now if we look at 2.5 MHz then we have a ratio of 20:1 now we are looking at a frequency error of 400 Hz, this is the reason we want to use the higher frequency.
    In theory you can calibrate to within 10-7 using WWV as a standard, however I know of no amateur equipment that accurate and or stable.
Now don't nail me for the simplification of the calculation above. I will not take the time to go into the detailed calculations for this. If you want to know more about this subject and the math related to it check out the WWV web site. Enough of this, on with the show.

First and foremost turn the rig on and let it worm up for a couple of hours ( at least one ) this will give it time to stabilize. Set the frequency tuning to the finest setting allowed.
Tune in WWV in the SSB mode, say USB. (set the readout on your rig to read 10.000.00) MHz. turn your band pass knob ( knobs) to the full clockwise position. NOTE: If you have a icom ic 746 pro leave the band pass knobs in the center position. This radio has a digital band pass and will require the band pass to be centered. You should be able to hear the audio just as if it were AM. If you hear a beat note ( the carrier) your rig is off frequency, if no beat note is heard great. Now listen for the 500 or 600 Hz tone, if the audio tone is constant (not changing in frequency) then you are done no change is required, if the carrier is audible or the tone is changing it is time to see how far off frequency we are.
A note here, the software program GRAM is only good to + - about 3 Hz., this however has NO bearing on the accuracy of our calibration (actually this is a comparison not a true calibration) See explanation later. With a little practice you can get the frequency to within a few cycles per minute by listening to the tone from WWV, it just takes time. Of course it will not stay that good, but that is another matter.

Now assuming you have connected your rig audio out (speaker) to the line in of your computer, start gram ( the spectra gram program), you should have a screen like this.

Set the options as they are above then click OK. The next screen should look something like this without the two red vertical lines.

To add the two vertical lines at 500 and 600 Hz click on pointers and set the values like so.

The vertical markers are just reference points. They may be off due to the timing of the sound card, and are used just to identify the 500 and 600 tone trace.
What we are interested in is the shape of the trace. This is why the + - 3 Hz and sound card timing is of no interest to us.
Now we are ready to check the calibration of our receive frequency.

The trace on the computer is just to get us close, you want to listen to the tone. That is what we will be using to determine if we are on or off frequency.
What we want to hear is a single pure tone that is not changing.

See GRAM display below of WWV audio signal with the 500 Hz tone.
Here we are on frequency note the single peak at 500 Hz (50 Hz/10) this is what we want to see. You will be able to hear the 500 Hz tone change if you are off.
If your rig is off at this point, tune the VFO to get the single peak and a single pure tone. Note the readout offset. This is your frequency error.

Below we are high by 2 Hz (note the double peak of the trace at 500 Hz) Notice the 500 Hz tone sounds like two tones changing in amplitude. This is due to the phase shift of the carrier and 500 Hz tone product.

And in the last shot we are off by 20 Hz note the double peak has spread. You can readily hear the phase shift change here.

 

If your rig is off you will need to adjust the MASTER oscillator. If you are not sure of how to do this don't touch anything inside your rig. It is best to note how much your readout is off and just tune off that amount rather than mess the rig up.
Don't forget to return your band pass knob (knobs) to the center after you are done.