Yo Nathan! On Mon, 14 Jun 2021 10:40:36 -0700 Nathan Owens wrote: > Sorry, it was MACx-1, but either way, I decided to go for an Adafruit > Raspberry Pi GPS "Hat", which does 1PPS. I do not recommend that HAT. There are much better ones available at similar prices. > I'll setup a raspberry pi > with RT_PREEMPT RT_PREEMPT is overkill. The best you can get on a RasPi is about 54ns accuracy. Due to the clock granularity of 54ns. > and run as a Stratum-1 Clock locally. But always have other chimers in your configuration file. > This should > help with better irtt timings. This can be done for <$100 if anyone > else wants super accurate time. For some definition of "super". > > Does anyone know if any MAC1-X GPS dongles or anything similar are > > available anywhere? They pop up now and then. Right now GPS parts are hard to find, much less at good prices. Search for Navisys GR-601W, GR-701W, or GR-801W. The "W" suffix says it outputs PPS. The MAC1-X, or any PPS over USB, will only get you to > 1 milli second because of the USB. RGDS GARY --------------------------------------------------------------------------- Gary E. Miller Rellim 109 NW Wilmington Ave., Suite E, Bend, OR 97703 gem@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