[hpsdr] 10Mhz reference

[Mike Seguin]

Glen,

Step one is to verify that your Jupiter has a valid 3D GPS fix. The 
Jupiter engines output 10 kHz and PPS right after they are powered up. 
Until you get a valid 3D fix, they are not accurate.

To verify you have 3D lock, look at the NMEA GPGGA string. You want to 
see a 3 in that line. This indicates 3D lock.

Mike

On 3/3/2017 7:49 AM, K4KV wrote:
> ***** High Performance Software Defined Radio Discussion List *****
>
> Hello,
>
> I have designed my own GPSDO using a Jupiter module with a 10khz
> output.  My reference
>
> TXCO has a feedback input and I divide that down to 10khz as well and
> compare the Jupiter
>
> to the TXCO 10khz output, run them through an exclusive OR gate then
> filter for the feedback
>
> voltage.
>
> Using a scope it appears they are perfectly locked.  It also appears the
> NMEA streams out of the
>
> Jupiter show quite a bit of data, I am assuming a lock to the satellites.
>
> However, when attached the Hermes, the 10Mhz reference clock shows WWV
> off by 50-70Hz.
>
> My question is: Do you need to also adjust the calibration inside PSDR?
> I was assuming the cal corr.
>
> factor should be the default of zero correction...
>
> 73
>
> Glen K4KV
>
> ps - the 10Mhz output at J20 on the Hermes is 800mv, I hope that is enough!
>
>
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-- 

73,
Mike, N1JEZ
"A closed mouth gathers no feet"