[Hammarlund] DDS for SP600?

[Eugene Hertz]

I was reading the december issue of ER and read an interesting article about injecting a DDS signal into a crystal socket for a Drake 4C. So I was wondering if anyone ever tried/thought of doing the same thing with an SP600 (I guess it would have to be a JX model)? Would seem a logical idea. Would give high stability and direct frequency readout (assuming you built the readout circuitry).
Thoughts anyone?
Eugene