Re: [time-nuts] Cheap jitter measurements

[Andy ZL3AG via time-nuts]

There's a "realtime" kernel available for Linux that improves timing - no idea 
if this would help in this situation.

See: linux-image-rt-amd64 in debian, for instance




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Re: [time-nuts] Weird Stuff WareHouse shutting down

[Andy ZL3AG via time-nuts]

On 9/04/2018, at 3:52 AM, jimlux wrote:

> Test equipment tends to be aged - Unless you have a particular need for a HP 
> 600 series microwave signal generator, there are probably better sources 
> available much cheaper that use more modern components. In this day and age, 
> I don't think people should suffer through 141T spectrum analyzers or even a 
> 8568- Spend your money an a nice USB unit instead.
> 
Blasphemy!


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Re: [time-nuts] Curious, how many t-nuts have 5065A

[Andy ZL3AG via time-nuts]

http://www.timeok.it/hp5065a-corner-3/

See: HP5065asnlist (serial number list)

On 23/02/2018, at 3:44 AM, Pete Lancashire wrote:

> no reason other then  curious
> 
> -pete
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Re: [time-nuts] Performance verification for time counters

[Andy ZL3AG via time-nuts]

HP 5359A Time Synthesiser?


On 30/11/2017, at 10:24 AM, Leo Bodnar wrote:

> I am looking for an established and widely accepted procedure for verifying 
> performance of high resolution time counters.
> 
> I have designed a time stamping counter for qualifying 1PPS signal 
> performance against external reference (e.g. 10MHz master clock.)
> 
> Simple design verification check I am doing at the moment is gating random 
> selection of master clock edges back into device's signal input and letting 
> the device measure this test signal offset against its reference clock - 
> which, for ideal design, should result in zero offset (modulo 100ns.)  My 
> results are roughly in line with what I expect to see 
> http://leobodnar.com/balloons/NTP/time-sampler-test1.png
> 
> Now, what would be recognised procedure for sweeping external input pulse 
> delay over few hundred ns in a controlled, measurable and repeatable way? 
> 
> I can see few naïve approaches:
> 1) Using selectively gated (or divided) reference clock followed by 
> adjustable delay line.  E.g. something like mechanically adjusted delay lines 
> used in HP test sets.  Or, perhaps, calibrated rigid coax sections?  
> 2) Slightly offset another master clock (e.g. second Rb oscillator) gated in 
> a similar way but without delay line, followed by statistical data analysis 
> 3) Trusted pulse generator with high resolution delay adjustment fed from the 
> same master clock as the counter 
> 
> I am looking for something with ~10ps accuracy, 100ns+ range, and reasonably 
> low jitter (~5ps or better.)  
> It is possible that the range needs to be split up (e.g. fixed rigid coax 
> delay line followed by a mechanically adjust section.)
> 
> This is a low budget fun project so something simple and common sense is 
> preferred to "price on application" NIST traceable equipment.
> 
> Thanks!
> Leo
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Re: [time-nuts] Machining some aluminum help!

[Andy ZL3AG via time-nuts]

Or go for thicker wall aluminium tube, oversized endplates and long bolts or 
threaded rods running the entire length down the outside of the tube so you're 
clamping both ends in one operation. No tapping required. Simples!




On 19/05/2017, at 6:16 AM, Tim Shoppa wrote:

> I bet you went to 0.25" wall square tubing only because you want to tap the
> walls for 4-40. Alternative designs can let you use much thinner material
> and a very different flange on the ends, but the costs will likely move
> towards welding/brazing rather than machining.
> 
> Tim N3QE
> 
> On Thu, May 18, 2017 at 12:54 PM,  wrote:
> 
>> Hi,
>> 
>> I have a square aluminum tube 5" X 5" with a .25" wall it's 8 1/2" long.
>> 
>> I need 20 holes in each end tapped for 4/40 and 1/2" deep.
>> 
>> This is for a Rubidium project.
>> 

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Re: [time-nuts] Machining some aluminum help!

[Andy ZL3AG via time-nuts]

Why are my eyes watering?

On 19/05/2017, at 5:03 AM, Bob Darlington wrote:

>  I had
> to soak my cavity ring in nitric acid for a month to get the tap out.
> 

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Re: [time-nuts] new year crashes

[Andy ZL3AG via time-nuts]

Agreed, but new years eve is a special case for emergency services in 
particular.


On 2/01/2017, at 2:38 AM, Bob Camp wrote:

> Hi
> 
> Insertion times that are convenient for some could be a major pain for 
> others. There is no 
> single “good” time to insert a leap second. You might argue that doing it 
> while the financial 
> markets are closed is a good idea. That sort of rules out the middle of the 
> week. You also
> could argue that you do it when everybody is on hand to fix things. That sort 
> of rules out
> weekends. With two simple “rules”, the entire week has been crossed off the 
> list ….
> 
> If you go back in the archives, you will find significant discussion going on 
> about dropping
> leap seconds altogether. That would indeed eliminate the need to schedule 
> them. It also 
> would eventually result in some odd adjustments to local time. 
> 
> 
> Bob
> 
>> On Jan 1, 2017, at 8:07 AM, Andy ZL3AG via time-nuts <time-nuts@febo.com> 
>> wrote:
>> 
>> 
>> If so, they should think about adding the leap second on the night of the 
>> 2nd wednesday of January, or such a time when things are quieter around the 
>> world.
>> 
>> Do they add the leap second at the same moment in time throughout the world, 
>> or are the clocks here in NZ running 13 hours and 1 second ahead of those in 
>> the UK for half of Jan 1st?
>> 

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Re: [time-nuts] new year crashes

[Andy ZL3AG via time-nuts]

If so, they should think about adding the leap second on the night of the 2nd 
wednesday of January, or such a time when things are quieter around the world.

Do they add the leap second at the same moment in time throughout the world, or 
are the clocks here in NZ running 13 hours and 1 second ahead of those in the 
UK for half of Jan 1st?

On 2/01/2017, at 1:54 AM, Adrian Godwin wrote:

> I wonder if someone wasn't ready for their extra second :
> 
> http://www.bbc.co.uk/news/uk-38482746
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Re: [time-nuts] Questionable content webcomic channels some time nuttery

[Andy ZL3AG via time-nuts]

At first, I avoided clicking the link as seeing it posted there with no hint as 
to the content, it screamed "this person's email account has been hijacked by a 
virus".

Once someone replied +1, I took a look and had a wee chortle.

On 8/11/2016, at 9:57 AM, Don Latham wrote:

> glad there are some other readers out there…
> 
>> On Nov 7, 2016, at 8:33 AM, Christopher Hoover  wrote:
>> 
>> +1
>> 
>> On Nov 7, 2016 4:05 PM, "Gregory Maxwell"  wrote:
>> 
>>> http://questionablecontent.net/view.php?comic=3346
>>> ___


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Re: [time-nuts] I love the smell of tantalum in the morning

[Andy ZL3AG via time-nuts]

Yes. Unless you're grinding it away with a dremel (which I wouldn't recommend 
as far as chemical dust is concerned), nibbling away with sidecutters would be 
trying to force the 2 ends of the component apart. That may be stressing the 
pads they're soldered to, leading to a possible pad lifting at some stage.

Any of the methods mentioned that heat both ends at the same time - allowing 
the component to be wiped off the board - would have to be the best, 
stress-wise.

On 6/11/2016, at 3:00 PM, Scott Stobbe wrote:

> For through hole parts sure, but I would not recommend that on SMD parts,
> the copper foil of a little pad is pretty easy to tear off and it's a royal
> pain if you have to mount a device missing some of its landing pads.
> 
> On Sat, Nov 5, 2016 at 4:37 PM, Tom Miller  wrote:
> 
>> I usually nibble away at the center of the part until it is two separate
>> pieces. Then unsolder each piece. Clean the pads off with wick then install
>> the new part.
>> 
>> Use a good sharp pair of flush cut side cutters.
>> 
>> Tom
>> 
>> 

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