Thanks Poul for the info. I will be getting the 4501 then.
I would like a copy of NTPns. Is the copy on your web page current? I may end up using a FEI 5081a and M12+T I already have with the 4501. I can probably program the frequency of 5081a to what is required. I'm looking forward to the M12M gps which I believe is out Dec this year. Google alerts doesn't seem to find much each week on the arrival of this unit. Cheers Geoff ----- Original Message ----- From: "Poul-Henning Kamp" <[EMAIL PROTECTED]> To: "Discussion of precise time and frequency measurement" <time-nuts@febo.com> Sent: Saturday, September 10, 2005 4:30 PM Subject: Re: [time-nuts] Soekris Net4801 vs NET4501 as Statum 1 timeserver > In message <[EMAIL PROTECTED]>, "Geoff Horner" writes: > >Hi all, > > > >Does anyone know which of the two Soekris boards makes a better statum 1 > >time server. > > The net45xx series does because you can make hardware timestamps > with it: > http://phk.freebsd.dk/soekris/pps > > >Anyone used a OCXO in either? > > Yes, both. Finding OCXO's with the oddball frequencies are the > hardest bits. > > >I have seen phk's results of the 4501, although > >that was tweaked at fair bit using an Rb oscillator. > > The timestamping performance would be the same without an Rb, > even without using an OCXO you will get much better performance > than with anything that needs interrupts to timestamp. > > Be aware that the normal NTPD can't really use this for anything, > the PLL is not tuned for such precision work. > > I have writte from scratch NTP server called NTPns which is geared > towards stratum-1 work with atomics etc, and you can have a copy > if you want. > > This is the stability display from a net4501 with an ISOtemp OCXO131 > OCXO and a Oncore m12+T GPS: > > Source m12_0: votes 6.000000 flags <UTC> los 0/15 update 1 SELECTED > stratum 0 delay 0.000000000 dispersion 0.000000088 refid [47 50 53 00] > last_ts 1126340906.000000006 last_delta 0.000000007 > 1: 11111111 -0.000000046 1.391e-07 > 2: 11111111 -0.000000059 1.456e-07 > 4: 11111111 -0.000000052 7.344e-08 > 8: 11111111 -0.000000031 1.525e-08 > 16: 11111111 -0.000000036 4.834e-09 > 32: 11111111 -0.000000030 8.111e-09 > 64: 11111111 0.000000044 6.030e-10 > 128: 11111111 0.000000007 4.264e-10 > 256: 11111111 0.000000011 3.015e-10 > 512: 11111111 0.000000030 1.317e-10 > 1024: 11111111 0.000000028 8.538e-11 > 2048: 11111111 -0.000000013 1.013e-10 > 4096: 11111111 -0.000000012 4.363e-11 > 8192: 11111111 -0.000000024 3.043e-11 > 16384: 11111111 0.000000006 6.043e-12 > 32768: 11111111 -0.000000035 4.342e-12 > 65536: 11111111 -0.000000033 2.434e-12 > 131072: 11111111 0.000000002 6.655e-13 > 262144: 11111111 0.000000009 4.418e-13 > 524288: 11111111 -0.000000002 2.961e-13 > > First column: integration time > Second column: precense bitmap for 8 samples > Third column: average offset [sec] > Fourth column: Allan variance after discipline. > > -- > Poul-Henning Kamp | UNIX since Zilog Zeus 3.20 > [EMAIL PROTECTED] | TCP/IP since RFC 956 > FreeBSD committer | BSD since 4.3-tahoe > Never attribute to malice what can adequately be explained by incompetence. > > _______________________________________________ > time-nuts mailing list > time-nuts@febo.com > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts _______________________________________________ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts