golgarfrincham at yahoo.com
Fri Jun 11 16:48:43 UTC 2010
> 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.
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
More information about the time-nuts