On some GPSDOs (like those made by Trimble that speak TSIP) you can disable
disciplining. Doing this usually reduces phase noise on the outputs, but in
this mode the frequency will drift over time. A lot of hams normally keep
disciplining on and turn it off when they are driving a radio.
OK. I would still be interested to see if anyone has plots on the close
in noise profile of the Lucents. The XO part has an Efrom OCXO and I
can assume it's similar to a generic OCXO. But the RB is an unknown - I
have no idea what to expect from that.
On a separate task, one of these days
kb...@n1k.org said:
> None of the GPSDOâs out there are great for multiplying direct to
> microwaves.
> Itâs not so much the phase noise as all the spurs (though phase noise does
> vary a bit).
Where do the spurs come from?
--
These are my opinions. I hate spam.
Hi
None of the GPSDO’s out there are great for multiplying direct to microwaves.
It’s not so much
the phase noise as all the spurs (though phase noise does vary a bit). For an
instrument frequency
source, they *assume* the input will be dirty and clean it up inside the
device. So again,
Hi
The inability to switch the ext input over to time mode may be why they
are still working on the F9T. I have gotten mine to work, darn if I remember
how I did it :) I seem to recall it is wired / config’d someplace odd on the
Sparkfun board. (like it measures the pps output maybe ….).
Bob
Hi Bob,
Thanks for your comments. The highest precision thing in my lab is a
5338a and that's only if I set the gate time to something really long so
that it renders a full 12 digits of info. Other than a "I wanna be a
time nut so let's see what it will do" - I never need anything near that
Hopefully if Sparkfun does a F9T, they will bring out a pad for TIMEPULSE 2.
On the F9P, I have been unable to change the settings for TIMEPULSE2... maybe
the F9P does not actually support it even though is is mentioned in the docs.
Sparkfun has their SPARKX division that does short runs
Hi
Pretty much all of these big old telecom beasts are “good enough” for “typical
use”. The gotcha
is that both of those terms are very much lacking in precision. Since this is a
precision sort of
thing, that may not be ideal :)
If 0.1 ppb is good enough for what you are doing, then they all
Hi
Well, Sparkfun is all out of F9P’s last time I looked. The Sparkfun version of
the F9T may be out in June or July. The F9T information
is lagging about 5 to 6 months behind the F9P at this point. With zero
information from uBlox, about all we can do is guess about
dates. If the raw modules
