[time-nuts] new member with questions NTP, PRS, GPS, ocxo

[Mark Spencer]

Regarding the NTP server another option is to buy a stand alone NTP server that can accept a 1pps and or 10 Mhz input, and feed it the GPS or other reference of your chosing.  I picked up a Datum unit from ebay which is currently fed 1pps from a Jackson Labs Fury.  It also accepts 10 Mhz as well which it will use in lieu of it's built in VCXO.  

I agree with the comments about the Fury being a nice plug and play GPSDO solution.   I thought long and hard about going the ebay route and acquring a used HP GPSDO to supplement my Thunderbolt and ended up buying the Fury.   That being said the price differnce between the Fury and a typical used Thunderbolt is signficant.

I would steer clear of the typical combined NTP, GPS units with TCXO's or VCXO's if you are interested in a using them as a source of a highly accurate 10 Mhz reference signal.   The VCXO in my datum NTP server is orders of magnitude less stable than a typical OCXO.

Installing a GPS antenna in a location with a clear view of the sky is also helpfull.





> 
> Message: 7
> Date: Fri, 17 Aug 2012 21:35:52 -0500
> From: Bill Dailey <docdailey at gmail.com>
> To: Frank Hughes <hp_ciscovss at yahoo.com>,   
> Discussion of precise time
>     andfrequency measurement <time-nuts at febo.com>
> Subject: Re: [time-nuts] new member with questions NTP, PRS,
> GPS, ocxo
> Message-ID: <7216E83F-8AAD-403A-8236-DD7D19B26B12 at gmail.com>
> Content-Type: text/plain;   
> charset=us-ascii
> 
> On a budget get a thunderbolt... If you want plug and play
> get a Jackson labs Fury.  I have my fury hooked up to
> small Ubuntu box and have a nice ntp server as well as a
> great reference.  Also, read, read, and read some
> more.
> 
> Doc
> KX0O
> 
> Sent from my iPad
> 
> On Aug 17, 2012, at 8:12 PM, Frank Hughes <hp_ciscovss at yahoo.com>
> wrote:
> 
> > Hi,
> > New guy here, seeking Oracular pronouncements for my
> time/frequency quest!
> > 
> > I recently acquired an HP 3336B, and subsequently
> converted it to a "C" model,
> > as all the HAM and related equipment here is 50 ohms.
> > 
> > The 3336 has "Option 004: High stability frequency
> reference". 
> > Operates at about 6Mhz....
> > 
> > I am trying to decide whether to fix the 3336 ocxo, or
> just use the other working
> > ocxo in the Agilent E8285A Spectrum Analyzer.
> > OR
> > It would really be fun to provision some type of
> Primary Reference and accurate 10Mhz source, and distribute
> the signal.
> > 
> > I found a bunch of them on ebay, but they are almost
> all in China....what is going on here?
> > 
> > Anyone ever had a good buying experience for this type
> of equipent from China? 
> > 
> > While decending through this particular
> worm-hole,  I realized that it would be great to have 
> > my own NTP server via GPS too. 
> > Found a bunch of GPS receivers w/ Ethernet and NTP
> server features, but none w/ ocxo, only vcxo and tcxo. 
> > Possibly it does not matter if the reference is the
> Stratum-1 GPS? 
> > Not sure what I am looking at here (obviously)
> > 
> > I only know a little about these topics, as where I
> work we have an Agilent_5071A, paired with a 
> > Symmetricom GPS PRS system. 
> > But as we have moved out of the old TDM and ATM
> technologies, we no longer need a Stratum-1 source,
> > (and the 5071A has used up all it's Cesium anyway). But
> it was fun and I learned many things.
> > 
> > 
> > So what I am trying to come up with now for home/shack
> is:
> > - An NTP server for our LAN 
> > - A very high quality 10Mhz source to distribute to all
> the HP and Agilent equipment here.
> > 
> > I have read enough forums to become dizzy, and would be
> glad to buy an HP Z3815A, or
> > an HP Z3816A or an HP Z3801A or...
> > I even found an HP 55300A, but w/o the shelf it is
> useless, 
> > (100 edge connector pinouts to decipher and wire
> manually???)
> > 
> > Advice much appreciated!
> > 73
> > Frank
> > KJ4OLL
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> 
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> End of time-nuts Digest, Vol 97, Issue 42
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