Re: [time-nuts] GPSDO control system

2014-03-28 Thread davidh
Howdy Charles, Could you tell us more about the PLL, what sort of phase comparator, filters and so forth. I'd be keen to duplicate and test your configuration. Thanks, david David wrote: How do you lock your OCXO to the PRS10? I just use a 1:1 PLL. Some will argue that phase

Re: [time-nuts] FEI-5660 Rubidium Oscillator

2014-03-28 Thread Bob Camp
Hi Crystals are susceptible to vibration. That’s pretty well documented. They have resonances in the mount structure. They have a 2G tip sensitivity. Audio when it “impacts” an oscillator induces vibration. If your noise source is a rocket engine, then the vibration is “non trivial”. You do

Re: [time-nuts] Sound impact Was FEI-5660 Rubidium Oscillator

2014-03-28 Thread Robert Atkinson
Back in 1997 when working on a car project I saw several failures of AD595 Thermocouple converter chips due to sound. In all cases the bond wire to pin 8 of the CERDIP package failed, presumably due to resonance (I took the top of the chips to check) A blob of non acid cure RTV silicone rubber

Re: [time-nuts] FEI-5660 Rubidium Oscillator

2014-03-28 Thread Bob Stewart
What about the other side of audio-phoolery: audio FFT?  I'm thinking more along the lines of an ARRL FMT. From: Tom Van Baak t...@leapsecond.com To: Discussion of precise time and frequency measurement time-nuts@febo.com Sent: Thursday, March 27, 2014 6:10

[time-nuts] HP 5065A with Patek Philippe analog clock coming up for sale

2014-03-28 Thread cdelect
Thought I'd give a heads up concerning a nice HP 5065A that I will be offering for sale in the near future. It has the Patek Philippe analog clock and is in pretty good condition. Fully checked out and aligned! Plot against a Hydrogen Maser looks great and beats the original HP specs handily.

Re: [time-nuts] GPSDO simulation tool

2014-03-28 Thread Magnus Danielson
On 26/03/14 22:42, Tom Van Baak wrote: Did some home-work on third-degree PLL parameters, so now I know why I failed, as I never tried to do it right. One thing that Tom's simulator isn't doing is calculating the parameters for the PID for you, or backwards what characteristics you will get.

Re: [time-nuts] FEI-5660 Rubidium Oscillator

2014-03-28 Thread EWKehren
All Rb's have XO's and with the exception of the HP5065C all Rb's influence long term stability only the only exception is the HP which uses a TC below 0.1.sec, and as Corbe demonstrated ADEV is controlled below 1 sec. by the cell. The same can not be said with other Rb's. Bert Kehren

Re: [time-nuts] Using GPS to Fine Tune a Rubidium Frequency Standard.

2014-03-28 Thread Mike George
Anders: I am a QEX subscriber and have that issue but I haven't built the circuit. The author referenced Brooks Shera as the basis for his work. He uses a Trimble Resolution T GPS for a PPS reference and an LPRO-101 Rubidium oscillator for the 10MHz. His circuit divides the 10MHz output from

Re: [time-nuts] Using GPS to Fine Tune a Rubidium Frequency Standard.

2014-03-28 Thread Ernie Peres
Hi Anders, please contact me offline and I will send you a copy of the QEX article. Rgds Ernie. -Original Message- From: Mike George mgeo...@tuffmail.us To: time-nuts time-nuts@febo.com Sent: Fri, Mar 28, 2014 7:43 pm Subject: Re: [time-nuts] Using GPS to Fine Tune a Rubidium

Re: [time-nuts] Beaglebone NTP server

2014-03-28 Thread Paul
On Wed, Mar 26, 2014 at 5:51 PM, Henry Hallam he...@pericynthion.org wrote: I have a Z3805A and a Beaglebone, and would like to set up an NTP server for the lab. Any kernel drivers and/or setup hints would be appreciated :) I've managed (almost by accident) to run my dev boards and related

[time-nuts] Japan / Time-Nuts

2014-03-28 Thread Tom Van Baak
I might be in Tokyo in late May (2014) with hopefully a spare day or two. Are there any geek technology or precise time frequency locations / activities / events / people I should seek out while I'm there? Are there any high-precision clock or time-nuts or vintage-electronics collectors in

Re: [time-nuts] Using GPS to Fine Tune a Rubidium Frequency Standard.

2014-03-28 Thread EWKehren
The QEX unit is a spin off of the Shera, how ever the DAC is only 12 bits covering the full tuning range of the Rb. Shera does it better with 18 bits and has additional features. I would not spend the money to get a copy. Bert Kehren In a message dated 3/28/2014 2:42:55 P.M. Eastern

[time-nuts] Another Arduino GPSDO

2014-03-28 Thread Eric Williams
I just saw Lars' postings on his design and thought I'd throw mine in since I've been working on a similar low-end goal but doing it a different way. Not really an Arduino, either, but it's based on an AVR processor and should be portable to an Arduino. Right now it's still on a solderless

[time-nuts] A little tail about using the time-nuts tricks at work

2014-03-28 Thread Magnus Danielson
Fellow time-nuts, Every now and then, a customer runs into trouble. You end up in these meetings where vendor and customers discuss troubles. I heard about this one and invited myself along. Turns out my friends at the customer was attending. Troubles involved dropouts and blips on a

Re: [time-nuts] Another Arduino GPSDO

2014-03-28 Thread Hal Murray
[Nice description. Thanks.] wd6...@gmail.com said: I'm sure the short-term stability isn't as good as a PLL, but averaging the errors over such a long period does have the advantage of making the sawtooth error pretty much irrelevant. You don't believe in hanging bridges? What do you mean

Re: [time-nuts] Another Arduino GPSDO

2014-03-28 Thread Eric Williams
I'm sorry, I don't recognize the reference to hanging bridges. I don't consider it a PLL because I have no way to measure phase differences within a cycle. I have some serial debugging output to see what the code's doing, but I'll have to think about how to organize it into graphs that would be

Re: [time-nuts] Another Arduino GPSDO

2014-03-28 Thread Hal Murray
wd6...@gmail.com said: I'm sorry, I don't recognize the reference to hanging bridges. I guess it was a good thing I mentioned it. Sometimes I feel like a broken record. It gets discussed here occasionally. There will be lots of comments in the archives. Starter version: tvb: Motorola

Re: [time-nuts] Another Arduino GPSDO

2014-03-28 Thread Eric Williams
OK, now I understand the reference, but not the significance in this context. The sawtooth error is below the resolution of the counter here. It does produce noise on the transition between capture counts that I am filtering out, but it should average out over the long-term integration that I'm

Re: [time-nuts] Another Arduino GPSDO

2014-03-28 Thread Bob Camp
Hi The problem is that it can / might / could / will create a “dc bias” in the noise. When you filter it, you get a bump rather than zero. If your GPSDO has a 47 ns wide sawtooth, that could be a pretty big bump. There’s no way to know if the bridge is seconds, minutes, or hours wide. You can

Re: [time-nuts] Another Arduino GPSDO

2014-03-28 Thread Chris Albertson
On Fri, Mar 28, 2014 at 5:15 PM, Eric Williams wd6...@gmail.com wrote: OK, now I understand the reference, but not the significance in this context. The sawtooth error is below the resolution of the counter here. I think you are right. It hardly matters for your application. I think you

Re: [time-nuts] Japan / Time-Nuts

2014-03-28 Thread John C. Westmoreland, P.E.
Tom, If you have time - you may visit New Japan Radio: http://www.njr.com/ 3-10, Nihonbashi Yokoyama-cho,Chuo-ku, Tokyo 103-8456, Japan TEL: + 81-3-5642-8222 / FAX: + 81-3-5642-8220 I believe there are people there that also deal or know those that know about vintage equipment in the area.

Re: [time-nuts] Another Arduino GPSDO

2014-03-28 Thread Eric Williams
Right, I should be able to get that from the TIM-TP message, but then what do I do with it? Not sure how I can apply a picosecond correction in this configuration short of adding a programmable delay line chip that would cost more than the GPS receiver did. -- eric On Fri, Mar 28, 2014 at 6:40

Re: [time-nuts] Another Arduino GPSDO

2014-03-28 Thread Bob Camp
Hi Since the output of your GPS (short term and long term) is likely much better than your ability to measure (using your setup), why not just drive the clock with the GPS? You would use far less power and have far fewer problems. Bob On Mar 28, 2014, at 5:55 PM, Eric Williams