I got a second Efratom. As you can see from a previous posting I own already an Efratom LPRO-101. This second one is owned by the institute I am working for and it doesn’t really belong to me. The intention is to build a NTP server and to use this Efratom LPRO-101 as stratum 0 source. I purchased it at Ebay and it’s coming again from Hong Kong / China. The price for this electronic part is 155 EUR. But there were already periods of time where you didn’t get it below 300 EUR.
After unpacking I run it for some days and I made my first measurements. The way how-to measure is identical as I described earlier. I run a NTP server with two 1PPS sources. One of this sources is the 1PPS signal from a GPS receiver which is my reference. The other comes from the Efratom. The 10 MHz output is divided by 10^7.
And here are the results.
Mon Jul 25 21:38:29 CEST 2016
Below one can see the offset of the second 1PPS ( 127.127.22.1 ) calculated out of the peerstats file.
ntp_shps -o -F 1 -x -0.5:20 -f png 127.127.22.1 .
This shows the difference between these two 1PPS signals.
ntp_shdiff -F 1 -t 20 -x -0.5:20 -f png 127.127.22.1 127.127.22.0 .
drift per second: .00000000008285582538 ppb: .08285582538000000000 drift per hour: .00000029828097138051 drift per day: .00000715874331313224 drift per month: .00021774510910777230 drift per year: .00261294130929326760
Without any adjustments this system much closer to the “real” clock than my first device. It has only an offset of 0.08 PPB. My first device is 3 PPB away from real 10 MHz.
Sun Jul 31 19:01:49 CEST 2016
And sometimes it’s even better.
This is the GPS based stratum 0 reference.
This is the offset messured from the peerstats file for the new Efratron.
And this is the difference.
drift per second: _.00000000000962494532 ppb: -.00962494532000000000 drift per hour: -.00000003464980315935 drift per day: _.00000083159527582440 drift per month: _.00002529435630632550 drift per year: -.00030353227567590600
All without any adjustments.