[time-nuts] EFC info on Trimble 34310-T OXCO
EWKehren at aol.com
EWKehren at aol.com
Sat Aug 23 16:23:34 EDT 2014
Charles
I was also not aware that James Miller had done a Shera, I have copied his
other unit I call a GPS PLL and my notes show a Clark but they are the
same. What I added was a op amp in the filter to drive low impedance OCXO
inputs and we use a $ 15 ublox M7. at 1 KHz. Right out of the box we get 1 E-10
using a Morion and I am turning it over to some Hams to play with the
filter. It was more of a test what can be done with a very low cost simple
circuit and not intended for time nuts. Would be the wrong direction.
As to Ed's and Bob's comments our projects are not able to compete with
commercial products and I do not think that should be our goals. Having spend
extensive time on temperature control, I limit my self to 10 C and use fans
on all Rb's and passive on OCXO's. Concern about vibration induced noise
on the OCXO made me remove the fan on the tbolt. Added a lot of mass and now
ordered some foam balls from China to fill the enclosure as some one
recommended. Foam has to be close cell so not to absorb moisture. Did also run
some foam pieces through a mixer with mixed results. Decided to wait for the
small balls and do moisture tests on both and fill a tbolt. Since I have
two identical units I will be able to compare..Goal is to slow the
temperature change to a rate that the GPSDO loop takes care of the frequency change.
Bert Kehren
In a message dated 8/23/2014 3:42:24 P.M. Eastern Daylight Time,
csteinmetz at yandex.com writes:
Ed wrote:
>I don't think you're correct about the Miller GPSDO containing a
>Shera controller.
Is there more than one "Miller GPSDO"? I was referring to this one,
by James Miller G3RUH, which uses a Shera controller and 10811 OCXO:
<http://www.jrmiller.demon.co.uk/projects/freqstd/frqstd.htm>
Answering my own question: yes, there appear to be at least two
"Miller GPSDOs," both by the same Miller. Here is another
(presumably the one Ed was referring to):
<http://www.jrmiller.demon.co.uk/projects/ministd/frqstd.htm>
Best regards,
Charles
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