David,
I've seen your comparison in the list archives. However, none of the
approaches I have seen published so far (including yours) exploit all the
possibilities I mentioned.
The Raspi having better community support doesn't help if the platform
itself
is unfit for the purpose. It might be OK as a general purpose NTP server if
you don't have any special requirements to accuracy, but for a PTPv2
grandmaster, having the ethernet behind a USB interface is a no-go.
Regarding the RF interference - I'm running a Ublox M8T module directly
mounted on the BBB via my custom GPSDO cape. It is working just fine.
Disabling the onboard HDMI encoder might be the "secret sauce" for success.
BR,
Matthias
===================================
Matthias, my feeling is that if you want a precision source, neither BB not
the RPi is a good solution. Maybe with all the tweak you mentioned the BB
approaches precision (for some values of precision). I see the RPi as
something which can provide far better NTP than simply using an Internet
source, something which will be adequate for the majority of users (for some
types of user!).
The RPi 4 doesn't have E/net over USB hence my comment on seeing a
comparison. The RF interference is to other parts of the spectrum - not
specifically 1.5 GHz GPS - and has been documented. I noticed it on either
145 or 435 MHz bands when testing. [Jim] Whether anyone has bothered to do
proper measurements I doubt.
Cheers,
David
--
SatSignal Software - Quality software for you
Web: https://www.satsignal.eu
Email: david-tay...@blueyonder.co.uk
Twitter: @gm8arv
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