[time-nuts] Discipline a rubidium driven net4501 with a Garmin LVC 18?
Christian C. Gruber
cg at chilia.com
Fri Oct 15 12:45:34 UTC 2010
Hi,
out of curiosity I want to build a ntp timeserver. I can remember some
epxerimets I carried out with a DCF77 receiver and a Cobalt Qube years
ago, however this never really worked out.
My plan is to buy a soekris net4501
(http://soekris.eu/shop/net4501/net4501_30_board_only_en.html) and
modify it to use a 10MHz signal from a rubidium source via a clock-block
(http://www.tapr.org/kits_clock-block.html). I read that a rubidium
source is not really necessary, but since I'm a chemist I'd like to have
something "atomic" in there that keeps my time when the GPS satellites
drop from the sky. I found some tested rubidium sources at
http://www.tenmhz.com/LPRO.htm, does anyone have experience with this
seller? Are these units better than the one from China sold on eBay?
Furthermore I'd like to get a 1PPS input from GPS as others already did.
However, I would like to use one of these Garmin GPS 18 LVC units (as on
http://time.qnan.org/) that usually work fine and provide a 1PPS signal
together with a NMEA output and connect it to the net4501 internal
serial port instead of the FatPPS (as John did:
http://www.febo.com/pages/soekris/). Is there a way to get
Poul-Hennings`s NTPns working with the GPS 18 as a PPS source?
Is there any specific reason why a 1PPS signal from another source (like
a Thunderbolt GPS disciplined clock) together with a FatPPS board would
give better results as my Garmin approach?
Altogether, this would cost about 450EUR [129EUR (net4501) + 49EUR
(clock-block) + 176EUR (rubidium standard) + 100EUR (used Garmin GPS 18
LVC)] excl. shipping and small stuff for a rather good time server, what
do you think?
Best regards and thanks for your help,
Christian
--
Christian C. Gruber
cg at chilia.com
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