OFC: This is reported to be made by Isotemp and equivalent to OCXO134-10 from them. Not a bad part, 5ppb vs. temp from -30 to +60C, -105dBc @ 10Hz. It's also the oldest, so probably has aged the most, which means its aging rate will likely be very low now.
CMAC: Can't find any information on this.
ISOTEMP: Hard to say, the OCXO143 series spans a couple decades of performance, and the -141 seems to be a custom-spec part. It could be a little better than the OFC (1ppb vs. temp, 115dBc @ 10Hz), or it could be a lot worse. Given that it's square wave output it might be harder to implement well.
I've received several OCXOs from eBay that were well off frequency (some 20ppm on a 5ppb part, and the EFC range insufficient to correct for it) and had poor stability as well (drift of some ppm with temp / time). Make sure you check them out before using.
thanks for the info, ve7xen.. (xen.. good call sign !) I saw your blog, I'm also planning to make a GPSDO like you wrote on your blog too.
Along with these few OCXOs, I also ordered and received a Navman Jupiter TU60 GPS receiver. This one has the 10Khz correlated output so I am hoping to use that with the OCXO to make a GPSDO. provided, as you say, it's not out so much that it can't be pulled in.
I wasn't pleased with what I received , the picture on the ebay sale shows a nice clean unit (of course!)
what I got was sufficiently rusted to give me some initial worries. It would seem that it was previously in a pretty harsh environment outdoors. I just hope it still works and has life left in it.
My goal is to have a decent 10Mhz reference on my bench, that I can use everywhere, so I can build a dual-slope ADC and perhaps get 7 or 8 digits from it, so I can have an accurate 10-12 digit frequency counter, so I can build an accurate DDS based function gen from it, so I can know my scope sweeps are timed accurately, etc.. etc.. there are so many uses for a good clock !
after 25 years, I am retired from my day job as an engineer (hoping to freelance now) and just starting out with an empty home bench, so I am on a limited budget, and I'm planning to bootstrap my bench with stuff I build myself. The first thing I need is a decent clock. After that it's all gravy