[time-nuts] HP 58540A Phase Noise Improvements

[Paul Christensen]

I am currently using a HP 58540A GPS-disciplined OCXO as the frequency 
reference to an ICOM IC-7800 transceiver.  I am looking to improve the phase 
noise performance of the 58540A.

Although some HP 58540A units contain the MTI 230-series OCXO, I have been 
considering the MTI 260 series for its superior phase noise performance but 
it uses a larger PC board footprint.  The PC board in the 58540A seems to 
have accommodated several OEM's form factors as evidenced by the PC board 
silk-screen.

Does anyone have any suggestions as a replacement OCXO with excellent phase 
noise approaching -160 dBc @ 1 kHz?  Are there any special precautions or 
other alignments required when dropping in a replacement OCXO?  Thanks!

Paul