From my experience, most precision 10 MHz OCXOs should be settable to within
5 ppb. If settability is not specified, it can be estimated from the tune
range and the number of turns of the adjusting device. A rule of thumb is
to use one point of resolution for every three degrees of rotation. The
10811 has +/- 10 Hz minimum - assuming they threw in some margin - 30 Hz
total range with 18 turns gives 1.4 ppb - you're doing quite well with 0.25
ppb.
But, of course the OCXO is probably aging 0.5 ppb/day...........
73,
Bob
On Fri, Nov 13, 2009 at 12:59 AM, Glenn Little WB4UIV <
glennmaillist@bellsouth.net> wrote:
I just got a system that allows me to compare the phase difference between
a reference and an external oscillator.
I am using a Vectron oscillator installed in a HP 5345A counter as the
external oscillator and a PTB-100 as the reference.
How close to the reference should I be able to set the OCXO?
After a 3 day warm up, it appears that I have gotten the OCXO to within
0.0025 Hz of the Rubidium reference.
I am checking with a strip chart recorder over a three hour period for the
next few days to see if the OCXO stays at this accuracy.
Is it really possible to set an OCXO this close or have I made some errors
in my computation of frequency offset?
Thanks
73
Glenn
WB4UIV
time-nuts mailing list -- time-nuts@febo.com
To unsubscribe, go to
https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
and follow the instructions there.
Glenn,
>From my experience, most precision 10 MHz OCXOs should be settable to within
5 ppb. If settability is not specified, it can be estimated from the tune
range and the number of turns of the adjusting device. A rule of thumb is
to use one point of resolution for every three degrees of rotation. The
10811 has +/- 10 Hz minimum - assuming they threw in some margin - 30 Hz
total range with 18 turns gives 1.4 ppb - you're doing quite well with 0.25
ppb.
But, of course the OCXO is probably aging 0.5 ppb/day...........
73,
Bob
On Fri, Nov 13, 2009 at 12:59 AM, Glenn Little WB4UIV <
glennmaillist@bellsouth.net> wrote:
> I just got a system that allows me to compare the phase difference between
> a reference and an external oscillator.
> I am using a Vectron oscillator installed in a HP 5345A counter as the
> external oscillator and a PTB-100 as the reference.
> How close to the reference should I be able to set the OCXO?
> After a 3 day warm up, it appears that I have gotten the OCXO to within
> 0.0025 Hz of the Rubidium reference.
> I am checking with a strip chart recorder over a three hour period for the
> next few days to see if the OCXO stays at this accuracy.
> Is it really possible to set an OCXO this close or have I made some errors
> in my computation of frequency offset?
>
> Thanks
> 73
> Glenn
> WB4UIV
>
>
> _______________________________________________
> time-nuts mailing list -- time-nuts@febo.com
> To unsubscribe, go to
> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
> and follow the instructions there.
>
