[time-nuts] RFX GPSDO - Anybody played with one of these?

bg at lysator.liu.se bg at lysator.liu.se
Wed Oct 3 01:35:38 EDT 2012


> On 10/2/12 2:36 PM, SAIDJACK at aol.com wrote:
>> Hello Paul,
>>
>> thanks much for the feedback!
>>
>> Yes, we think we have identified a nice combination of oscillators, GPS,
>> and firmware that seems to work pretty well. The GPSTCXO units cannot be
>> compared to a lower cost $150 Thunderbolt in terms of phase noise or
>> stability
>> of course, and they have CMOS 10MHz outputs, but then the  TB's cost
>> around
>> $1500 new I guess.
>>
>> We think the GPSTCXO's and LC_XO type units will work quite well
>> wherever
>> standard OCXO's are used today, and power/size/weight are an  issue.
>>
>
>
> Intriguing.. Can it handle the Doppler, etc., for a cubesat in LEO?
> (7km/s)  The total Doppler isn't usually the issue (the GPS satellites
> are moving faster, after all), but the receiver may not work for high
> velocities, high altitudes?

GPS SVs moves at around 4km/s, but nevertheless there are still COCOM
limits implemented in nearly all receivers (never break both 504m/s and
18km height)

--

   Björn





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