Re: [time-nuts] Allan variance by sine-wave fitting

> at telling you it was sitting on top of a power transformer. It didn’t matter > a lot I did ten runs of various standards that were within a couple of meters of the bench; the TimePod did not move the entire time. Each standard had a different looking PN plot, so I'm pretty sure the 120 Hz

Re: [time-nuts] Allan variance by sine-wave fitting

Am 26.02.2018 um 20:20 schrieb Tom Van Baak: Fun fact -- there's a wide spur at ~2 Hz on the 5065A phase noise plot. What do you think that is? On a hunch I opened the front panel and reset the blinking amber battery alarm lamp, and voila, that noise went away. Makes sense when you think of

[time-nuts] Replacement Backup Battery for 5065A?

On 2018-02-26 11:00 AM, Corby wrote: Also I usually remove a battery A2 and install two shottky diodes on the underside of A2s chassis jack. Non-battery units have an A2 that just has these two diodes on it. On mine, I didn't bother with schottky diodes, I just used half of a bridge

Re: [time-nuts] Allan variance by sine-wave fitting

Hi Yet another reason to nuke the battery and the A2 board. It is amazing just how small a signal can mess things up at the levels involved in a good frequency standard. The old “when in doubt, throw it out” mantra may be a good one to keep in mind relative to a lot of add on features…. how

Re: [time-nuts] Replacement A9 boards for the HP 5065A

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Re: [time-nuts] Replacement A9 boards for the HP 5065A

Well all this capacitor talk has me actually looking for the 5 uf cap. When I picked up the 5065a it didn't work. This was in the late 90s and no manual was available at that time. I reverse engineered the system and guess what cap was bad? The integrator. So not being all that smart, I hooked 2 X

Re: [time-nuts] Replacement A9 boards for the HP 5065A

>> The only thing I could provok, was that almost all capacitors I >> tried were sensitive to touch. Most ceramic caps are sensitive to "micro phonics" via the piezoelectric effect, which can translate mechanical stress into electrical noise.

Re: [time-nuts] Allan variance by sine-wave fitting

On Mon, February 26, 2018 2:29 pm, Tom Van Baak wrote: > BTW, a trick for blinking LED's -- use two of them out of phase: one that > the user sees on the front panel and one that is blacked out or hidden > inside. A flip-flop (Q and /Q) or even a set of inverters is all you need. > The current

Re: [time-nuts] Allan variance by sine-wave fitting

> Yet another reason to nuke the battery and the A2 board. Yes. Then again, the effect is very minor when you look at the PN and ADEV plots. It falls into the category of "look how sensitive a TimePod is" more than "look how bad a 5065A is". And remember it's just a warning lamp, with a

Re: [time-nuts] Allan variance by sine-wave fitting

Hi, On 02/26/2018 08:42 PM, Gerhard Hoffmann wrote: > Am 26.02.2018 um 20:20 schrieb Tom Van Baak: >> Fun fact -- there's a wide spur at ~2 Hz on the 5065A phase noise >> plot. What do you think that is? On a hunch I opened the front panel >> and reset the blinking amber battery alarm lamp, and

Re: [time-nuts] Replacement A9 boards for the HP 5065A

In message , Wayne Holder writes: >>> The only thing I could provok, was that almost all capacitors I >>> tried were sensitive to touch. > >Most ceramic caps are sensitive to "micro phonics" via the piezoelectric

[time-nuts] Assorted replies, and request for info

Request for data from an off-list friend who is looking for info on an Ovenaire OCXO and/or the instrument it was used in: > Could you send a post on my behalf asking if anyone else has an > Ovenaire 42-15 or if not, a Spectracom 8131 Frequency Standard Oscillator. This is from Dennis

Re: [time-nuts] Allan variance by sine-wave fitting

This note is a follow-up to Ralph Devoe's ADEV posting earlier this month. It's a long story but last week I was in the Bay Area with a car full of batteries, BVA and cesium references, hp counters, and a TimePod. I was able to double check Ralph's Digilent-based ADEV device [1] and also to

Re: [time-nuts] Selling Time and Frequency Equipment Or "just saying"

Corby, Thanks for your informative posting. I concur. Let me add a visual that echoes your comments. It's the same plot that I attached in the note about Ralph's lab. For those of you who can't view email attachments see [1]. The plot is ADEV of 4 typical lab frequency sources: - A 5071A in

Re: [time-nuts] Allan variance by sine-wave fitting

On Mon, 26 Feb 2018 02:43:04 -0800 "Tom Van Baak" wrote: > This note is a follow-up to Ralph Devoe's ADEV posting earlier this month. > > It's a long story but last week I was in the Bay Area with a car full of > batteries, BVA and cesium references, hp counters, and a

[time-nuts] Setting time on Z3801A and KS24361

I currently have one each that think it is 13 Jul 1998. That's ballpark of 20 years ago. I assume it's 1024 weeks. The time of day is good. Has anybody set their time recently? I thought I knew how to set the time, but the last time I tried, it didn't work. I have done it in the past, but

Re: [time-nuts] FRK

Bert's M100 Rb teardown photos are now here: http://leapsecond.com/bert/m100.htm /tvb - Original Message - From: "ewkehren via time-nuts" To: "Discussion of precise time and frequency measurement" Sent: Sunday, February 25, 2018 6:05 AM

Re: [time-nuts] Replacement A9 boards for the HP 5065A

Group, After 40 years of doing PID control for industrial processes, I'm used to an error tolerance of 10E-3. So I couldn't understand an integrator with a 10 K resistor and a 5 mfd capacitor. But this is time nuts, and the tolerance is more like 10E-13. An integrator as a controller takes any

Re: [time-nuts] Replacement A9 boards for the HP 5065A

On Sat, 24 Feb 2018 23:44:16 -0500 Charles Steinmetz wrote: > Given the relatively low resistances at the op-amp inputs (10k ohms), > the ultra-low input "bias" (leakage) current of the 6240 is simply > unnecessary. Any offset due to the input currents (within the

Re: [time-nuts] Allan variance by sine-wave fitting

Hi One of the TimePods that I had access to in the past was particularly good at telling you it was sitting on top of a power transformer. It didn’t matter a lot which instrument the power transformer was in. For some weird reason it was a good magnetometer at line frequencies. I never bothered

Re: [time-nuts] Replacement A9 boards for the HP 5065A

We have decided to go with the 1012 do we need to do any thing with pin 5Bert kehren Sent from my Galaxy Tab® A Original message From: Attila Kinali Date: 2/26/18 9:53 AM (GMT-05:00) To: Discussion of precise time and frequency measurement

Re: [time-nuts] Allan variance by sine-wave fitting

> BTW: Do you know the cause of the oscillations in the 5065 vs BVA plot? The ADEV wiggles aren't visible with normal tau 1 s measurements. But since the TimePod can go down to tau 1 ms, when I first measure a standard I like to run at that resolution so effects like this show up. Once that's

Re: [time-nuts] Replacement Backup Battery for 5065A?

Thanks for all the suggestions! I think I'll take the conservative approach for now and just remove the battery (fortunately it has not leaked!) and run from a UPS-backed outlet. If I ever decide I want to reinstall the battery, it would be to keep the 5065A "original" and not for real backup

[time-nuts] Replacement Backup Battery for 5065A?

I agree with Bert, I always remove the battery. They will cause grief eventually! Use either in UPS or the separate DC input jack on the rear. One note, if the battery is removed and the battery charge switch is in the position to light the front panel lamp you will degrade the stability of