http://elecraft.85.s1.nabble.com/Frequency-reference-for-the-K3-directly-off-a-GPS-tp7606275p7606278.html
while flipping through the slides. You'll need headphones to get
> Hi Sverre,
>
> This type of 10 MHz output has short term stability problems and isn't
> suitable for direct drive of a K3 (imho). It *could* be used, if
> integrated over a long time constant (thinking many seconds) to drive
> a D.O., but that would take additional circuitry. It might be quite a
> project.
>
> You're probably better off with A GPSDO or a Rubidium source. Even a
> plain OCXO would work if you can keep it calibrated.
>
> 73,
> matt
> W6NIA
>
> On Thu, 13 Aug 2015 06:36:31 -0700 (MST), you wrote:
>
>> Some recent GPS modules (ublox Neo 7) have a programmable output that in
>> addition to the 1 pps output can be programmed even to output 10 MHz. This
>> output has a lot of jitter as it seems to be derived from a 48 MHz clock
>> which is divided down in such a way as to generate a mix of short and long
>> cycles but so that the average frequency is maintained accurately at 10 MHz.
>>
>> A description can be found here
>>
https://sites.google.com/site/g4zfqradio/u-blox_neo-6-7 and performance is
>> partly described here:
>>
https://www.febo.com/pipermail/time-nuts/2014-August/086257.html>>
>> My question is regarding the K3 external reference input. Is this source
>> good enough to drive the K3 reference? Can the K3 clean up the jitter
>> internally, or does the K3 require a source with much less phase noise?
>>
>>
>>
>>
>>