Seen recently (2007?) on eBay is a 245MHz OCXO for about US$25.00 (the vendor has since upped the price to about $50, due to demand apparently.)
NO LONGER ON EBAY
eBay item # 280512317880
I bought one and might try it in my Picastar. It draws about 300mA (cold) and about 100mA warm, from 9V supply. It's 2" square.
Phase noise at 1KHz is -130dBc, and at 10KHz -152dBc.
PCB
I was able to source a one-off PCB to mount the OCXO. The PCB has an LM317 regulator to provide 9VDC and variable supply to allow the OCXO to be set precisely to frequency.
Data sheet was obtained from Wenzel™
Data sheet for the VECTRON™ equiv. (thanks Rich, AJ3G)
Click for larger picture.
