[time-nuts] OFC (McCoy?)(Isotemp?) OCXO

Richard Moore richiem at hughes.net
Thu Oct 30 23:55:49 UTC 2008


Just received this OCXO from mr. fluke in China. Took exactly 14 days  
from time of order to get here to W. Washington. Hooked it up like  
the Isotemp 134 diagram. He said it would work, and it works perfectly.

The Isotemp spec EFC voltage range (positive slope) is 0 to the ref.  
voltage, in my set-up, +8.0V. On this OFC unit, I found no change in  
frequency until the EFC gets to about 1.28V. It reached 10 MHz, to  
within 1E-9,  at about 3.33V, with a total frequency span (1.28V to  
7.9V) of 10.6E-7, or very roughly 1.6E-7/V.  Unlike the Isotemp 134,  
this one has no trimming adjustment, so the only freq. control is via  
the EFC line, whose slope seems quite non-linear.

Output is a very clean sine wave, about 2.8Vp-p unloaded and 1.8Vp-p  
into 50 ohms.

This thing reaches temp fast and seems to be quite stable, but I  
won't have any reliable data until it is used in a more permanent way  
with stable supply voltages. Seems like a very nice unit.

Dick Moore




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