[Test-Equipment] "No spectrum analyzer" phase noise test setup of a 15.6 MHz TCXO?

[Ray, W4BYG]

The Kenwood TS-590 S (G) list server on yahoo has an interesting 
discussion going on about the fairly cheap Chinese TXCO's that are being 
sold as an optional replacement for the factory supplied 15.6 MHz 
oscillator in the TS-590S(G) series transceivers.  It seems there has 
been reports of phase noise issues on some Chinese replacements.  This 
can result in unnecessary and unwanted noise being transmitted or 
received +/- 10 to 15 KHz from the operating frequency.

I am aware that today's modern procedures would use a fairly expensive 
spectrum analyzer to measure the phase noise of such an oscillator.  
However, most hams today do not have access to a SA, Therefore in true 
ham fashion (meaning cheap), surely someone knows of an inexpensive way 
to bench check the phase noise of an oscillator.

Has anyone any experience in doing so?  I surmise building a good 15.6 
MHz notch filter would be required.  In addition, a way would be needed 
to measure 80 to 90+ db down at 10 KHz to 5 KHz away from the 
fundamental.  Some of us have good HP power meters that have dynamic 
range of that or a little more.  That would require the notch filter to 
be very good (not sure one could be made that good even in a good ham lab).

Anyone care to share their insight on what it would take to make such 
measurements without a SA?
Your attention is appreciated.
Ray, W4BYG

-- 
I'm no longer young enough to know everything!