[time-nuts] To improve a Tbolt?

Bruce Griffiths bruce.griffiths at xtra.co.nz
Fri Nov 21 22:06:30 UTC 2008


John Miles wrote:
> I've upgraded the graph on the http://www.ke5fx.com/tbolt.htm page to show
> the performance of my Thunderbolt from the TAPR group buy (in orange) next
> to the traces for my older unit before and after the 10811 upgrade.
>
> There is no upside to tinkering with the OCXO on the TAPR units, unless you
> have something that can beat a 10811.  You could replace it with a rubidium
> source and get better short-term stability, but I don't think swapping one
> quartz OCXO for another would be a useful thing to do.
>
> -- john, KE5FX
>   
John

What power supply did the TAPR Thunderbolt use?
Have you considered using a variant of the Wenzel supply filters to
cleanup the spurs in the 1-10kHz region.
This is trivial with the low current -12V supply but would require some
design effort for the +12V and +5V supplies.
Using a more modern opamp (simplifies biasing) to augment the
performance of such a filter for the higher current supplies would be
worthwhile.
Even dropping the spur level by 20dB is probably worthwhile.

Bruce



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