[time-nuts] Elpromatime (Was Re: time-nuts Digest, Vol 191, Issue 28)

[Dave B]

A funny looking "SMA" ended cable....

https://elpromatime.com/portfolio_page/time-server-nts-pico/  (Scroll down.)


Also, has anyone tried this?  (An alternative to Meinberg on Windows
perhaps...)

https://elpromatime.com/downloads/    I'd take a look, but I don't run
Windows here any more.


Cheers n beers.

Dave G8KBV

------------------------------------------------------------------------
On 28/06/2020 12:44, time-nuts-request at lists.febo.com wrote:
> Message: 2
> Date: Sun, 28 Jun 2020 04:32:49 -0700
> From: Tom Van Baak <tvb at LeapSecond.com>
> To: time-nuts at lists.febo.com
> Subject: Re: [time-nuts] Vibration isolation of quartz oscillators
> Message-ID: <e4f6a47c-9963-6414-6c57-8aa199acbcf2 at LeapSecond.com>
> Content-Type: text/plain; charset="utf-8"; Format="flowed"
>
> About slabs and stability... Around the world there must be a hundred 
> precision time labs, including official NMI (National Metrology 
> Institute) labs that contribute to the calculation of UTC itself. You 
> run into photos of these labs and their T&F gear on the web all the time 
> when you search for time nutty stuff. Those of us with home labs -- even 
> if just a few vintage frequency standards -- can relate.
>
> Anyone, one of my favorite lab photos is from VSL, the Dutch Metrology 
> Institute. Photo attached. [1]
>
> Spend time time pan/zooming around the gear in the photo. The usual 
> suspects: hp 105 quartz; TimeTech (I think); lots of SDI 
> (Spectradynamics); also Truetime or Symmetricom stuff; maybe that's an 
> old Tracor/Fluke VLF receiver on the far right (?); and of course lots 
> of Stanford Research SR620 counters, the TIC still used by almost every 
> time lab.
>
> But what really caught my eye was not just the four hp 5071A in the 
> foreground but *how they are mounted* -- on top of massive granite blocks!
>
> The answer is [42]. In this case the question is how many cm wide is a 
> 5071A cesium clock? That means the scale of the 1600x1200 JPG is about 
> 1.5 mm per pixel, which implies the blocks are exactly 50x50x40 cm. 
> That's nearly half a ton of mass. Note the unknown mystery support 
> technique underneath. Either they had spare black granite blocks lying 
> around their office that looked really cool or they put some thought 
> into vibration isolation of their clocks. Still, tell me more about 
> inner tubes.
>
> I personally don't know the background of this setup. If you have VSL or 
> .NL connections please let us know. I remember when I first talked with 
> them about their lab many years ago, the UTC(VSL) BIPM stability numbers 
> seemed unusually good to me for "a national lab with only 4 cesium 
> clocks" so the granite blocks left a heavy impression on me.
>
> Anyway, for those of you looking for maximum quartz oscillator / 
> frequency standard stability and vibration isolation, maybe the granite 
> block isolation idea is worth looking into. I know Michael mentioned 
> space constraints for his BVA so this rock solid slab solution might not 
> help him.
>
> /tvb
>
> [1] I can't find the original vsl.nl web photo that I remember. But a 
> recent one like it is:
>
> https://elpromatime.com/wp-content/uploads/2018/10/VSL.jpg , via:
>
> https://elpromatime.com/portfolio_page/time-server-nts9000 , via:
>
> many google image searches for words including: VSL dutch metrology .nl 
> caesium 5071a clocks UTC BIPM
>
>
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