With my filter , I had good success and 5 K is not too high , Ulrich Sent from my iPhone
> On Aug 1, 2016, at 11:46 AM, Bob Camp <[email protected]> wrote: > > Hi > > ….. until you discover that you picked the *wrong* capacitor manufacturer and > you have > more noise from leakage in the cap than you did to start out with :) In > general “big C and > small R” is the better solution than “big R and small C”. > > The pesky part is that with electrolytic caps, the whole “noise current” > thing changes as > the voltage moves around. You go to measure things and by the time the gear > is set up, > the noise has dropped. Turn it all off, come back the next day and it’s noisy > again. > > An even more subtle issue can be capacitor temperature coefficient on really > long Tau filters. If C > changes (due to temperature fluxuations) faster than the settling time of the > filter, you get noise. Charge > is the same so delta C gives delta V. > > I *wish* I could tell you that was all purely theoretical. Unfortunately it’s > based on empirical data > collected in the “how could I be so stupid” fashion. > > Bob > >> On Aug 1, 2016, at 11:21 AM, KA2WEU--- via time-nuts <[email protected]> >> wrote: >> >> A good filter in the cable is highly recommended, 5 KOhm & 1000 uF cleans >> many things >> >> >> In a message dated 8/1/2016 11:12:51 A.M. Eastern Daylight Time, >> [email protected] writes: >> >> Hi >> >> It’s just very standard FM modulation math. The only gotcha is the >> (often unknown) bandwidth of the EFC port. Even on a precision >> OCXO, it might be <10 Hz, it might be over a KHz …. The trap many >> fall into is the “small angle” restriction. You can get into modulation >> indexes that will get the second and third order terms contributing. >> It’s more common to see on vibration, but it can happen on a noisy >> EFC. >> >> Bob >> >> >>> On Aug 1, 2016, at 9:46 AM, Attila Kinali <[email protected]> wrote: >>> >>> Moin, >>> >>> I need some formulas that relate EFC noise to the (added) phase noise of >>> an OCXO. It shouldn't be too difficult to come up with something. But >>> before I make some stupid mistakes, i wanted to ask whether someone >>> has already done this or has any references to papers? My google-foo >>> was not strong enough to find something. >>> >>> Attila Kinali >>> >>> -- >>> It is upon moral qualities that a society is ultimately founded. All >>> the prosperity and technological sophistication in the world is of no >>> use without that foundation. >>> -- Miss Matheson, The Diamond Age, Neil Stephenson >>> _______________________________________________ >>> time-nuts mailing list -- [email protected] >>> To unsubscribe, go to >> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >>> and follow the instructions there. >> >> _______________________________________________ >> time-nuts mailing list -- [email protected] >> To unsubscribe, go to >> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >> and follow the instructions there. >> _______________________________________________ >> time-nuts mailing list -- [email protected] >> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >> and follow the instructions there. > _______________________________________________ time-nuts mailing list -- [email protected] To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
