[GPS_Standard] Oscillator selection and preformance

[Stanley Reynolds]

Oscillator selection has some issues in my mind. 
Getting info on old parts can be a problem, just trying to figure if the oscillator has a ECC input. The exception is the classic HP 10811 and 10544 which are well described on line. As a result it would appear they fetch a good price at auction. My guess at the ranking is:
The age and how well it has been treated over the decades unknown.

1 10811A
2 10811-6011 (reduced specs at manufacturing)
3 10544 (lower due to oven switching glitches and older age and maybe the crystal cut)
4 (clones of the HP by Ovenair and Piezo found in equipment made by HP where a 10811-6011 would be)
5 Newer designs made in the last 10 years like the Efratom just discussed.

I'm a newbie and trying to learn while limiting the amount I spend, the oscillator does have a big input into the performance and cost of the final device. This makes it's selection important.
Even if you over come the problem of getting a part that works, you may not be happy till you have a understanding of how well it works. Looking at the log of corrections produced by the monitor program and comparing this to other oscillators with the goal of reducing "+F" and "-F" with a increase in "=". Then with the best longer time averaging too get the best performance. Would also like to test the difference of various mods such as power supply and adding insulation to the oscillator. To measure the effect would need to vary the room temp and record this as well. 
If a series of alternating +F and -F with large variations in the sample count, indicating over correction then maybe an adjustment to reduce the size of the fine adjustment by reducing the ECC control range. 


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