Re: [time-nuts] Thermal impact on OCXO

On Mon, Nov 7, 2016 at 10:34 AM, Scott Stobbe wrote: > Here is a sample data point taken from http://tycho.usno.navy.mil/ptt > i/1987papers/Vol%2019_16.pdf; the first that showed up on a google search. > > Year Aging [PPB] dF/dt [PPT/Day] > 1

Re: [time-nuts] Do the HP 5334A & 5335A counter/timers take the same oven oscillator?

In general, any 10811 with an edge card type connector in interchangeable in any instrument, in terms of basic functionality. The only differences are that various part numbers in the 10811 family are selected for certain critical specs. Certainly, between the 5334 and 5335, they are

Re: [time-nuts] GPS Model ?

I've got some older Oncore stuff too. The specs sound dated but are orders of magnitude better than needed for NTP servers. It is the kind of thing you turn on then it just runs for years. Get a good outdoor antenna. That said, last time, a few months ago when I was looking for an under $10

Re: [time-nuts] GPS Model ?

Mitch, You have either a 6 channel PVT-6 or a 6\8 channel Basic Oncore. Both share size, power and I\O specifications. I'll send the Basic Oncore Engineering Notes to you off list. We'll also post the Engineering Notes to our website for others who might be interests in this early nineties

[time-nuts] Do the HP 5334A & 5335A counter/timers take the same oven oscillator?

Would it be possible to remove an OCXO from an 8334A 100 MHz counter/timer and fit it in a 8335A 200 MHz counter/timer? Would the TXCO from the 8335A then fit in the 8334A so that the 100 MHz unit? Are the OCXOs similar, identical or incompatible? I expect a detailed look at the service

[time-nuts] DDS spurs (was: Secondary phase noise standard & FE405)

On Sun, 13 Nov 2016 11:03:31 -0500 Tim Shoppa wrote: > Some AD DDS app notes give examples of spurs and choosing nearby (but not > exactly on freq) numbers that are much less bad for spurs - or at least > that move the spurs outside the cleanup filters/loops. I don't know of a

Re: [time-nuts] Secondary phase noise standard & FE405

Hi The “sure fire” way to reduce the spurs is to go to a divisor that “fits” in to the DAC bit width. If you have a 12 bit dac, those points happen at Fclock / 2^12. For Time Nut sort of stuff that’s pretty coarse tuning. Bob > On Nov 13, 2016, at 11:03 AM, Tim Shoppa

Re: [time-nuts] Secondary phase noise standard & FE405

Some AD DDS app notes give examples of spurs and choosing nearby (but not exactly on freq) numbers that are much less bad for spurs - or at least that move the spurs outside the cleanup filters/loops. I don't know of a general example or even code that does this in a general way. One paper I like

Re: [time-nuts] quartz drift rates, linear or log

Hi > On Nov 13, 2016, at 9:34 AM, Artek Manuals wrote: > > Tom et all > > While our instinct based on some "pre- knowledge" of the aging and drift > processes is to try and fit these to linear or logarithmic curves there is a > third possibility . That is, in fact

Re: [time-nuts] 5071A with ATTENTION flashing

Hi Tom It looks very clean inside. I think they should be from some lab. There is one with a label CEVA xx on it. I told him all the information I collected from the serial port. As a reward to travel 200km help him determine the status of these 5071s, he gave me 2 PRS10 rubidium

Re: [time-nuts] quartz drift rates, linear or log

>> http://leapsecond.com/pages/tbolt/TBolt-10day-fit1-e10.gif > Hi Tom, > > Fascinating when you've done that linear fit - many of the plots now look > very similar, > suggesting environmental conditions? From that it would now be nice to log > temperature, > pressure, humidity, (& mains

Re: [time-nuts] quartz drift rates, linear or log

Hi Tom, Fascinating when you've done that linear fit - many of the plots now look very similar, suggesting environmental conditions? From that it would now be nice to log temperature, pressure, humidity, (& mains voltage?), and see if there is any correlation there. Wonderful to see

Re: [time-nuts] quartz drift rates, linear or log

Tom et all While our instinct based on some "pre- knowledge" of the aging and drift processes is to try and fit these to linear or logarithmic curves there is a third possibility . That is, in fact the aging is not exactly either and may be better represented in fact be some kind of

Re: [time-nuts] Secondary phase noise standard & FE405

Hi > On Nov 13, 2016, at 2:55 AM, Gerhard Hoffmann wrote: > > Am 12.11.2016 um 23:52 schrieb Bob Camp: >> Hi >> >> Yes, the FE-405 uses a DDS and a cleanup. Inside the cleanup loop the DDS >> spurs come >> straight through. Since the FE-405 compensates for all sorts of

Re: [time-nuts] quartz drift rates, linear or log

Thanks for all the comments on this thread. Here is the first set of replies: Don Latham: > Interesting, Tom. I don't think I see any of those pesky grain boundary > shifts or readjustments in the lattice structure? If I remember, these > can cause instant shifts in frequency that do not

Re: [time-nuts] 5071A with ATTENTION flashing

> Since the ion pump current was dropping slowly.(80uA to 76uA in 1 hour), is > it possible to be back to normal? Hi Li, Yes, is it possible. Never give up on ion current. Give it hours, give it days if necessary. Monitor the LCD or syst:print? periodically and plot the trend. The trend may

Re: [time-nuts] Swagelok and metric tubing question

In message , Gary Woods writes: >On Sat, 12 Nov 2016 13:05:56 -0800, you wrote: > >>Does it leak through cracks or migrate through metal? > >I was kinda wondering about that. Isn't H the escape artist of the >periodic table? Indeed. In

Re: [time-nuts] Secondary phase noise standard & FE405

Am 12.11.2016 um 23:52 schrieb Bob Camp: Hi Yes, the FE-405 uses a DDS and a cleanup. Inside the cleanup loop the DDS spurs come straight through. Since the FE-405 compensates for all sorts of things, the DDS moves around a lot. Even a one bit change on a DDS will move spurs around. With an

Re: [time-nuts] 5071A with ATTENTION flashing

HI I just came back from another 5071a seller. #1-#3 fatal error: max emult. #4 fatal error: overcureent (about 80uA) I put the tube from #1 to #4. #4 became a "max emult" one. I think the tube #1 is really dead and the circuit of #4 is functional. Since the ion pump current was dropping