[Elecraft] Frequency Calibration

[DGB]

My K-3's frequency appears to be off. I didn't notice it until I worked 
a couple of locals on our net freq. of 28.355 and had to use the RIt to 
tune them to my freq.

Zero-beating WWV at 10khz actually reads 9.999.6.

The rig had been on most the day and I did try Method 2 (zero beating) 
on page 50 of the manual but didn't seem to make much of a difference.

Is there a way to calibrate K-3  without a signal generator.

73 Dwight NS9I