I have changed my Hartley VXO. It is so tight I can lay my hand on the coil and the frequency will not move!
It is variable to 5KHz with solid lock. The only draw back is in order for it to start up on the crystal as main tuning source or in other words, at or near the crystal frequency, it must be set about 5 KHz above. Another way to explain it, is if I set the VXO to the crystal's frequency it will have a very hard lock. But, when I turn it off and then back on again it will come up out of lock usually far below frequency. If I tune it back into lock, it will end up at 5KHz above frequency with hard lock again. I can turn it off and back on and be at same frequency. If I tune down to even 2KHz above crystal freq. and turn off then on, it will be way out again.
Also, the PLL is more solid. Before I could hear it rail jumping. I believe it is because of the higher Q
I will post when I figure it out...lol