[time-nuts] 10 mhz accuracy for a satellite system

[Bob kb8tq]

Hi

One thing to watch on the TBolts - the ocxo’s used in them got better as the 
years went by. An early one likely will not do quite as well as a later one. They
also updated the firmware as time went by, same basic issue - later is probably 
better ….

Bob

> On Feb 4, 2019, at 8:51 PM, Richard Solomon <w1ksz at outlook.com> wrote:
> 
> There have been some Trimble Thunderbolts over on that auction site
> that were being sold for $80 each (not surplus Telcom ones).
> I grabbed two and they work.
> 
> My antenna was a "hockey puck" style antenna sitting on the window
> sash, facing South.
> 
> 73, Dick, W1KSZ
> 
> Sent from Outlook<http://aka.ms/weboutlook>
> ________________________________
> From: time-nuts <time-nuts-bounces at lists.febo.com> on behalf of Grant Hodgson <grant at ghengineering.co.uk>
> Sent: Monday, February 4, 2019 11:15 AM
> To: time-nuts at lists.febo.com
> Subject: Re: [time-nuts] 10 mhz accuracy for a satellite system
> 
> Paul
> 
> The keyword is GPSDO - GPS disciplined oscillator.  The vast majority of
> these will give a 10MHz output.  The long term accuracy is the same as
> the GPS navigation system, which for most purposes is similar to that of
> national standards.  GPSDOs are more stable than most rubidium standards
> in the long term, and GPSDOs are extremely common in most laboratories.
> 
> The Trimble Thunderbolt is very common and available on the surplus
> market, as is the HP Z3801A.  James Miller (G3RUH) used to sell an
> excellent GPSDO.  There are other home-brew designs available if you
> want to build.   These have all been extensively characterised if you
> want the details.
> 
> If you want to buy new, then there are products such as the Fury and
> Firefly from Jackson Labs; , U-Blox have many offerings (not sure if
> they do a GPSDO though).
> 
> Google GPSDO or GPS frequency standard, or check the leapsecond.com
> website for more information - there's loads out there, it's just a case
> of using the right term in the search engine.
> 
> regards
> Grant
> 
>> Date: Sun, 3 Feb 2019 23:43:10 -0000
>> From: "Paul Bicknell" <paul at bicknells.f2s.com>
>> To: "'Discussion of precise time and frequency measurement'"
>>       <time-nuts at lists.febo.com>
>> Subject: [time-nuts] 10 mhz accuracy for a satellite system
>> Message-ID: <D1F28D64EDD440EC834753538090F381 at precision380>
>> Content-Type: text/plain;     charset="iso-8859-1"
>> 
>> 
>> Dear all
>> I currently use a 198 Khz off air standard but I can no longer use  600 khz
>> since it moved from Rugby
>> I have herd a lot about varies frequency references that use satellites
>> This technology has improved immensely & become more affordable over the
>> past 5 years
>> 
>> So can a standard locked to a satellite be as good as a Rubidium ?
>> 
>> What accuracy can I achieve for a satellite system below ?800 as I am not
>> familiar with the latest that are on offer?
>> 
>> Regards Paul Bicknell  South Coast UK
>> 
>> 
> 
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