[time-nuts] Z3815A

Arthur Dent golgarfrincham at yahoo.com
Fri Jun 11 16:48:43 UTC 2010

> Hi
> The 260's are better for  environmental  than a 10811, same / worse than a
> 1938. The  "typical" 260 beats the "typical" 10811 or 1938 on short term /
> medium  term stability. There are some 10811's and 1938's that will indeed
>  beat some 260's for short term stability.
>  Bob
One of the GPSDOs I've had running for some time is an HP Z3811 with 
a a 1998 date code and a MTI 260 OXCO. Before you say I'm crazy, Z3811 
is what the labels on the chips say. The name on the outside of the unit 
is Lucent RFTG-u REF1.  Another similar Lucent unit had a clone of the 
260, same size and pin out, but I have no idea if the specs are close, 
and that OXCO was an OFC MC895X4-015W with a 1999 date code. 
Both these OXCOs are 5.000000Mhz.

Like most Lucent units the RFTG-u REF1 was made to run with another 
back-up unit for redundancy, needed an interconnect cable, and has no
information available. I managed to figure out a way to make it work as a 
standalone unit and ran the 5Mhz from the OXCO thru a QBits amplifer to 
give me 5Mhz output instead of the Lucent standard of 15Mhz. I haven't 
carefully checked it against the other GPSDOs I have running but with the 
modifications I made to allow it to work solo, it seems to be a pretty good 
plug-and-play unit.  


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