[time-nuts] Using HP5071A with dead tube along with GPS

[Bob kb8tq]

Hi

The PPS input on the 5071 does *not* set the frequency of the device. To do so would “break” the 
Cs ( = you use the beam to get frequency). The *only* thing the PPS input gets used for is to reset 
the *time* to sync with UTC.

Bob

> On Dec 19, 2019, at 5:56 PM, Taka Kamiya via time-nuts <time-nuts at lists.febo.com> wrote:
> 
> My experiment is not going well so far.  I have NOT done any tuning.  Just connected 1 pps out from GPS to 1 pps IN on 5071A.  Frequency keeps increasing, which I think is weird.  I thought it might just be unstable without proper parameters, but no.  Over last 24 hours, it kept going up.  I was about to start reading the 5071A manual.  Likely as TVB says, it will likely be needing quite a bit of refining loop parameters.  One unknown is, in this current state (fault), if OCXO is even steerable.  1 pps WAS detected and menu option did tell me so.  
> 
> I didn't know you can put 5071A in (Cs tube only) STAND-BY mode...  Mine is dead so it's in permanent stand-by.  It's initial boot sequence detects this and shuts it down.  
> 
> On a slightly different topic, my PRS10 + GPS experiment is working rather well.  I haven't done any tuning and using default for everything.  I'm going to wait about a month before doing so.  Loop constant is 1 day, so it may take quite some time to completely stabilize.
> --------------------------------------- 
> (Mr.) Taka Kamiya
> KB4EMF / ex JF2DKG
> 
> 
>    On Thursday, December 19, 2019, 5:34:55 PM EST, Mark Sims <holrum at hotmail.com> wrote:  
> 
> I've actually done this...  Lady Heather has built in "alternate disciplining" algorithm for the Thunderbolt.  I tricked up some code to use this along with a TAPR-TICC to make a GPSDO.  The first (rather crude) hack worked pretty well.  I haven't had a chance to do it properly... yet.
> 
> The idea was to allow the 5071A to run with the CBT in standby for applications that do not require the cesium goodness.
> 
> -------------
> 
>> A fun (and actually very useful) project would be to turn it into a 
> GPSDO
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