Dear time-nuts:
I have several FEI FE-5680A rubidium oscillators running and am looking for
any alignment information that might be available.
I can successfully communicate with them via the serial port and can control
the DDS to change output frequency. However, there are several pots
I recently purchased some FEI FE-5650A option 58 rubidium oscillators. They
are basically the same as the 5680A unit, but in a different (3x3x1.4 inch)
form factor. The following applies to the oscillator versions with the Direct
Digital Synthesis board that has the Analog Devices AD9830A
I just posted my rather long dissertation on the FE-5650A and FE-5680A
synthesizer board. A critical observation is that the F=reference frequency
value returned by the S command is NOT the value that the unit is actually
operating at as shipped from the factory. It is the value that the
Attached is my program for calculating the frequency divisor words for the FEI
FE-5650A and FE-5680A rubidium oscillators with the AD9830A based DDS board.
It compensates for the difference between the R=reference freq that the 'S'
command returns (the minimum C-field value) and the frequency
I am looking for advice.
I have one of the group buy thunderbolts (thanks for all the work on
this) and would like to use it as a local network time source.
Are there timekeeping preferences between using the thunderbolt as a ref
clock for ntpd or connecting it to gpsd and using the gpsd to
That's a good question: on the computer side, can a single serial port be
used for both 1PPS (for ntpd purposes) using one of the modem control
signals and for serial gps monitoring without having to write custom code?
Didier KO4BB
PS: I would advise against going inside the TB and adding the
Decent thermal management of the FE-5650A can be a problem. It is a small,
compact object dense with electronics and the rubidium physics package that
runs at over 100 degrees C. There are two metal plates in the unit. One is
the baseplate of the physics package. It is bolted edge on to
