[time-nuts] Symmetricom 1111C OCXO question

Hello all, I've a C OCXO (inside a Symmetricom 5045A that is inside an Oscilloquartz OSA 5585) that refuses to start. It seems that one voltage regulator is not operating, with only 2V at its output while it should have (I think...) around 12V. I've partially analyzed the circuit, and it

Re: [time-nuts] Symmetricom 1111C OCXO question

Hi Normally that sort of circuit has a “boot strap” pull-up resistor that weakly biases the diode to get things running at start up. Bob On Apr 3, 2014, at 11:08 AM, Javier Herrero jherr...@hvsistemas.es wrote: Hello all, I've a C OCXO (inside a Symmetricom 5045A that is inside an

[time-nuts] NIST Launches a New U.S. Time Standard: NIST-F2 Atomic Clock

Full story at http://www.nist.gov/pml/div688/nist-f2-atomic-clock-040314.cfm Edésio ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.

Re: [time-nuts] Symmetricom 1111C OCXO question

Hello! Yes, I was thinking something like that, but was not able to find it. After analyzing somewhat more, I'm finding that the problem seems more subtle. Since the gain of the operational is 1, and there is a positive feedback (the diode bias from the output), the output voltage should

Re: [time-nuts] Symmetricom 1111C OCXO question

Other idea than leaving the 6K8 resistor? On Thu, Apr 3, 2014 at 5:08 PM, Javier Herrero jherr...@hvsistemas.eswrote: Hello all, I've a C OCXO (inside a Symmetricom 5045A that is inside an Oscilloquartz OSA 5585) that refuses to start. It seems that one voltage regulator is not

Re: [time-nuts] Symmetricom 1111C OCXO question

On 03.04.2014 18:25, Azelio Boriani wrote: Other idea than leaving the 6K8 resistor? Yes... I would prefer to know why the little thing has stopped working. The 6k8 resistor has also probed to be a marginal solution. The operational amplifier is a Burr-Brown one (don't have the p/n at hand

Re: [time-nuts] NIST Launches a New U.S. Time Standard: NIST-F2 Atomic Clock

Wow, if 1 second in 300 million years is correct, that's around 1 E-16th. M On Thu, Apr 3, 2014 at 2:51 PM, Edesio Costa e Silva time-n...@tardis.net.br wrote: Full story at http://www.nist.gov/pml/div688/nist-f2-atomic-clock-040314.cfm Edésio

[time-nuts] maybe OT: GLONASS

I do not have a GLONASS receiver running at home at this time, but the media reported a total GLONASS outage a day or so ago. Was it real or just rumor? A co-worker in the lab at my day-job says he thinks he caught a GLONASS RX acting badly. Just technical curiosity. Sorry for BW.

Re: [time-nuts] NIST Launches a New U.S. Time Standard: NIST-F2 Atomic Clock

It's true that this is really a feat given the difficulty of measuring these systematics. Not to toot my own horn but... http://www.nist.gov/pml/div689/20140122_strontium.cfm . even just a few months ago we were talking about mid E-18 using an optical clock.

Re: [time-nuts] maybe OT: GLONASS

They apparently uploaded bad ephemeris data to the system and confused the receivers. It took them about 12 hours to straighten it out.  ---Kenton A. hooverken...@nemersonhoover.org+1 415 830 5843 I do not have a GLONASS receiver running at home at this time, but the media reported a

Re: [time-nuts] maybe OT: GLONASS

Some details: http://gpsworld.com/glonass-gone-then-back/ Outage map (adjusted color version attached): http://gpsworld.com/wp-content/uploads/2014/04/glonass_problem-300x210.jpg /tvbattachment: 2014-glonass-outage.gif___ time-nuts mailing list --

[time-nuts] Water on Enceladus - What does this imply about NASA'a ability to measure frequency?

I just read about a discovery of a liquid water ocean on Saturn's moon Enceladus. The method used was to measure the velocity of a spacecraft as it makes a close fly-by. Gravitational anomalies will cause the spacecraft to speed up or slow down as it flies over massive objects like mountains.