On 6/26/12 2:34 PM, Dave Hart wrote:
On Tue, Jun 26, 2012 at 9:11 PM, Majdi S. Abbas <msa@latt.net> wrote:
On Tue, Jun 26, 2012 at 04:33:35PM -0400, Robert E. Seastrom wrote:
Word around the campfire is that the 18x is jittery compared to the 18.
The 18x is much worse than the 18LVC. Thankfully I still have 2 18LVCs... but that said, given the hockey puck design, and that Randy already has an antenna, I wouldn't recommend this approach anyway. It's really only suitable next to a window, or in a short, wooden structure.
I agree the Garmin GPS 18x LVC solution is only appropriate near a window, or in a short wooden structure. David J. Taylor's experience was the older GPS 18 LVC had a substantially less sensitive receiver, so that his needed to be mounted outside, while his 18x LVC works inside.
The area where 18x LVC underperforms the 18 LVC is the jitter of the timing of its NMEA output relative to the leading edge of the PPS. Configured correctly, this should matter very little, and only transiently at startup where ntpd first uses the NMEA end-of-line timestamp (possibly fudged to bring it closer to the top of second) to "number the seconds" before engaging the PPS. I don't recommend attempting to use any NMEA source without PPS. With it, I don't understand why Majdi finds the 18x LVC much worse.
Does anyone use or prefer the 5Hz version of the 18x LVC? ~Seth