[time-nuts] Raspberry Pi TCXO Hat

[Richard Laager]

On 11/2/19 2:55 PM, Achim Gratz wrote:
> The one for the Ethernet controller is useless even for the seemingly
> intended application.  Replacing the main crystal with a TCXO may or may
> not help NTP performance depending on how much temperature effects are
> currently dominating it.

Right, I don't expect a benefit there. Since the board has both, if I
got one, I'd probably wire them both up just because.

>> It's a rather permanent modification, as you have to desolder the
>> stock crystals and replace them with wires going to the hat. I'm not
>> 100% sure how to order the hat yet, but they gave a price of $46 (USD)
>> via email.
> 
> You'd be much better off taking not of the injection point and then use
> a GPS timing module that can produce a clean 19.2MHz clock.  I still
> have that way down on my to-do list; although I was going to try and
> inject the clock without actually desoldering the crystal so it would
> still work even when the GPS module doesn't provide a clock.

How would it work to have two crystals connected in parallel?

-- 
Richard