[Boatanchors] Need Xtal Frequency Conversion Formula

[Duane B. Fischer, W8DBF]

Hi All, 	
	
Can one of you please give me the formula to convert the frequency on a HF
crystal to its counterpart in 'actual' listener MHZ? Such as, a crystal from ICM
has 8.5 written on the top of it. What does this equal in actual listening MHZ?
For instance, I know that 11.5-12.0 MHZ is shown on the crystal as 18 MHZ. Is
there a formula to convert that 18.0 or how does the listener know it equals
11.5-12.0 MHZ on the receiver dial?	
	
I have the formula for VHF and UHF, but nothing for HF. Thank you very much.	
	
Duane W8DBF