[hpsdr] external 10MHz reference input

[John Marvin]

I think there is a misunderstanding here. When I was referring to small 
jumps of 0.5 Hz (perhaps larger in the 10/6m band) I was referring to 
the behavior of the TCXO when it is enabled. If you have enabled the 
external clock input then the TCXO is no longer involved in providing a 
10 Mhz reference to the fpga.  If your GPSDO is not locking properly 
then you are switching back and forth between your GPSDO providing the 
10 Mhz reference, and no 10 Mhz reference. When there is no 10 Mhz 
reference then the 122.88 Mhz VCXO is just free running, which can 
easily be 30 to 40 Hz off. Hopefully an adjustment to your signal level 
will fix the locking problem.

John
AC0ZG

On 5/17/2013 11:28 PM, H.A.Meijer wrote:
> ***** High Performance Software Defined Radio Discussion List *****
>
>
>
> Hi,
> thanks for your thoughts about the freq jumps from the 10MHz osc.
> You are talking about "just 0,5 Hz' but my Hermes is jumping 30 to 40 
> Hz when on 10/6 mtr and with transverters (MF=28MHz) use.
> This is very annoying and for me not the so called "high performance"  
> I'm looking for.
>
> I did change the R141 and still see that is has some locking problem 
> to my external 10MHz, now and then.
> I will do some measurements at that circuit, maybe my 10MHz level is 
> to low..
>
> Bert
>

-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.openhpsdr.org/pipermail/hpsdr-openhpsdr.org/attachments/20130518/69872fd5/attachment-0004.htm>