[time-nuts] new GPSDO kit

paul swed paulswedb at gmail.com
Sun Apr 6 11:05:33 EDT 2014


I was thinking the same thing and its power consumption's quite low. Will
also guess may be easy to drive from a 12 V battery. Though I have not
hilltopped and many years. I used to.
Regards
Paul
WB8TSL


On Sat, Apr 5, 2014 at 9:10 PM, Dave Brown <tractorb at ihug.co.nz> wrote:

> Sounds like an ideal reference for a microwave hilltopping event.
> DaveB, NZ
> (ZL3FJ)
> ----- Original Message ----- From: <SAIDJACK at aol.com>
> To: <time-nuts at febo.com>
> Sent: Sunday, April 06, 2014 6:19 AM
> Subject: Re: [time-nuts] new GPSDO kit
>
>
>  Hello Brooke,
>>
>>  Can  you say more about what this means?
>>>> "It  generates a low-noise 10MHz signal with typically better than
>>>> 1E-010 precision and accuracy (0.1ppb) on average"
>>>>
>>>
>> let me explain. I took some measurements over night, see attached files.
>> This was done with the unit shielded from airflow and sitting on a bench,
>> and
>> the time constant increased by a bit to account for the benign no-airflow
>> environment.
>>
>> You can see that the ADEV at any time from 1s to 10,000s averages and
>> beyond is about 1.3E-010 worst case. So you can assume that the  average
>> accuracy (because of GPS being the absolute reference) and relative
>> precision (the
>> ADEV around the average value) is about 1.xE-010 on a  typical unit.
>>
>> Also note that the second plot shows a standard deviation of the TI
>> interval of 13.3ns which is significantly better than the 25ns spec.
>>
>> Lastly, the performance of 3E-012 at 10,000s is almost 3x better than
>> spec.
>>
>> This was a random unit I grabbed that had been sitting on a shelf for some
>> months, and I only let it run for ~15 minutes after power-on before I
>> started the measurement.
>>
>> This is one of the beautiful features of the TCXO we use: it does not
>> require long retrace and warmup periods. It runs pretty much right out of
>> the
>> box, even after months in storage. An OCXO based unit probably would have
>> required 8+ hours to stabilize from its retrace after such a long
>> off-period.
>> In fact this unit ran at only about 1.5ppb error before disciplining
>> started, meaning the TCXO and our firmware kept that frequency accuracy
>> over
>> several months on the shelf without power.
>>
>> So you could go to a work-site, set up the unit and wait about 15 minutes,
>> then get a really clean, accurate, and stable reference signal.
>>
>> Hope that makes sense,
>> Said
>>
>>
>>
>>
>> In a message dated 4/4/2014 16:40:45 Pacific Daylight Time,
>> brooke at pacific.net writes:
>>
>> Hi  Said:
>>
>> Can  you say more about what this means?
>> "It generates a  low-noise 10MHz signal with typically better than 1E-010
>> precision and  accuracy (0.1ppb) on average"
>>
>> Have Fun,
>>
>> Brooke  Clarke
>> http://www.PRC68.com
>> http://www.end2partygovernment.com/2012Issues.html
>>
>> SAIDJACK at aol.com  wrote:
>>
>>> Hello everyone,
>>>
>>> sorry for the  plug, but we just announced a new $568 complete GPSDO
>>> reference  kit.
>>>
>>> This unit is a tiny desktop unit with 10m  antenna, power supply, cables,
>>> CD, and other accessories. It is a low  cost addition to our Fury GPSDO
>>>
>> line,
>>
>>> and contains a really good  TCXO, a uBlox GPS receiver, and various power
>>> options. I believe this  is the lowest-cost real GPSDO in mass production
>>> available on the  market right now, and being a true GPSDO it has  some
>>>
>> fairly
>>
>>> good  phase noise and stability specs.
>>>
>>>
>>>  http://www.jackson-labs.com/assets/uploads/main/LC-XO-
>> Plus_PressRelease.pdf
>>
>>>
>>> bye,
>>> Said
>>>  _______________________________________________
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