Thanks for the replies! Should the `scope show the issue? I have
access to a very good SA but am always loathe to use it in case I blow
the front end, as at this low a frequency it needs the "absolutely no
DC" input port, and DC blocks that I have are iffy this low. Thanks,
after dinner I will look at it again with the `scope for a start, now
you have all given me some great advice as to possible causes. After I
have taken some more measurements with the `scope I may change the
crystal and then the divider. Andy is undoubtedly right in that a
buffer trigger may be the ideal, but I am not competent to design a
circuit with correct values and KISS seems appealing until simpler
fixes are checked out ;)



-- 
Best regards,
 Chris                            mailto:[email protected]