Yo Richard! On Wed, 13 Nov 2019 11:38:40 -0600 Richard Laager via devel <devel@ntpsec.org> wrote:
> The tentative plan is to upgrade/reinstall Ubuntu, switch to NTPsec, > and deploy NTS. That's all easy. Yup. > It'd be nice if we could also replace the dead GPS master clock with a > directly connected GPS receiver, so we get PPS into the server (e.g. > via a serial port). That would make them stratum 1. Yup. > For this project, we could buy an equivalent current > generation EVK-M8T for $250 from e.g. Digi-Key. I think you have an extra zero on there. I do this for about $25. > Is there an easy way to split an RS232 level PPS (and optionally the > GPS's TX for gpsd) into three systems? Sure, real RS-232 has a lot of drive power to get the +/-12V to work. > What is the most cost-effective way to create three stratum 1 servers? The T version u-blox are way overkill for a stratum 1. A simple u-blox NEO-M8N for $10 will do. Then $5 for a TTL to RS-232 converter. Get one of these NEO-M8N for $7: https://www.ebay.com/itm/Replacement-NEO-M8N-GPS-BDS-Dual-mode-Module-Flight-Control-Satellite-ATGM336H/182622902135 Get the 5V for it by cuting up an old USB cable. Then convert the TTL TX/RX to RS-232, with connector, for $3: https://www.ebay.com/itm/RS232-SP3232-TTL-to-male-serial-port-TTL-to-RS232-level-conversion-serial-S6J6/112608133090 Add a GHz power divider for $10 and run all 3 on one antenna. I do it all the time. RGDS GARY --------------------------------------------------------------------------- Gary E. Miller Rellim 109 NW Wilmington Ave., Suite E, Bend, OR 97703 g...@rellim.com Tel:+1 541 382 8588 Veritas liberabit vos. -- Quid est veritas? "If you can't measure it, you can't improve it." - Lord Kelvin
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