[time-nuts] FE-5650A option 58 tuning word for 10 MHz output

Mathias Weyland mathias at weyland.ch
Tue Jan 3 11:55:32 EST 2017

On 2017-01-02 12:18, Attila Kinali wrote:


Nice to see you around here ond au der es guez nois!

> May I ask what you want to achieve? Resp. what you need a 10MHz
> reference for?

I've always been wondering about those devices, I guess out of pure
curiosity. Once I learned that those were available for cheap I knew
I had to get one. But there is a secondary goal, which is to have
a standard around to check my other gear against every now and then.
Lately, I've been building and repairing 1.3 GHz radios and lost
some time because I did not realize how much off both of my service
monitors where. I could get away with a properly calibrated OCXO
but the Rb was so much more sexy. So for the most part I need the
10 MHz for my own entertainment. :-)

> In general I would agree with Bill Houlne's comment that it's 
> probably
> easier to use a different reference that already has a 10MHz output.
> Also keep in mind, that an output that has been designed as an PPS 
> output
> might not work as well as an output for 10MHz.

Yes I agree with that, but I'd also say that based on the reading I
have done, it would be foolish to assume to get something that is
guaranteed to work anyway. With all the things that could go wrong in
general (dead unit, worn-out discharge lamp, drifted sweeping 
of the oscillator etc.), the 1 pps to 10 MHz conversion for this 
model(!) seems fairly straight forward. In fact the only issue I've 
facing so far is the one that I'm trying to resolve in this thread. And
even if this cannot be resolved, the converted unit is still suitable 
my application.

On the output issue you are rising: This particular model has a DDS 
takes a 50ish MHz reference and synthesizes another frequency which is
a power of 2. A coax cable is taking that to a divider board where it's
brought down to 1 Hz. This is all happening outside of the physics
package. The plan is to reconfigure the DDS to synthesize 10 MHz 
and bring out that coax. I would have to open a hole on the face plate
to do that, but I'm fairly confident that this outer enclosure does not
contribute to the actual magnetic shielding of the chamber... All
modifications are strictly outside of the physics package (i.e. no
water jet cutting...)

> I am not master of desaster on this list, but it's usually ok to 
> offer
> this kind of stuff, as long as it is time-nut related.

OK thank you and hope to meet you soon!


More information about the time-nuts mailing list