[hpsdr] external 10MHz reference input

[H.A.Meijer]

Hi Joe,

Yes well the problem is also that my Hermes boards(2x) seems to have 
problems to lock correctly to my
GPS 10MHz source.
It's has a 2v tt sinus wave output (1Vtt into 50Ohm) and that into the 
Hermes input gives locking problems (also freq jumpings).
I did a mod, R141, to the input buffer/clamper but it did not bring me a 
satisfying result, still freq jumping/ out off lock for short times.

Bert
> Hi Bert,
>
> As you know, external 10 MHz input is provided on all the HPSDR boards so that the user may use a 10 MHz source of your choosing.  Naturally, the user needs to select a reference source that is suitable for the application he has in mind.
>
> For transverter work, realistically, you should be using a Rb-vapor frequency standard or a GPS-conditioned frequency standard as the 10 MHz ref signal for your HPSDR board and be using that same reference source to lock the LO of your transverter too, of course.  In such an arrangement you will certainly achieve the “high performance” you are seeking.   I have no problem whatsoever using my HPSDR system at 1296 MHz and above with rock solid frequency control using such an arrangement.  Using a TXCO simply isn’t the way to achieve your desired goal in this case, in my opinion.
>
>   Good luck with your project!
>
> 73,  Joe K5SO
>
>
>

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