Review on Enhance Your Navigation Experience with the Garmin 18x LVC GPS Navigator Unit by Jim Escobedo

I have a Garmin 18x LVC GPS connected to a serial card installed in a Debian Linux 'squeeze' box (which comes with the Setserial, GPSD and NTP configured). USB based GPS devices are useless for accurate time setting. The GPS 18x LVC requires 5 volts (red wire) and for this I use a special StarTech.com 1 Port PCI RS232 Powered Serial Adapter Card (PCI1S650PW). The card can be configured to provide 5 or 12 volts (or no supply) to pin 9 of the RS-232 DB-9 connector and can be powered either from the PCI bus itself or from the PC power supply directly via the onboard Molex be supplied with electricity. flexible power connection. (I used the last option). Once the jumpers were set and the card installed, no Debian drivers were required, Setserial recognized the card as a 16550A UART with a 921600 baud database. quite weak, so mounting outdoors is the best option as the GPS itself is weatherproof. For me, this location gives the GPS a clear view of the sky, but a 5m cable is not enough to get to a computer in the house, so I replaced almost all of the original serial cable (which is potted) in 18x LVC ). The wires (especially the three signal wires including the PPS) are also *VERY* thin. So I cut off the original cable next to the GPS unit itself and extended it with my own cable that goes back to the computer and ends in a DB-9 serial connector. In this case, be sure to use a shielded cable. A serial connection basically requires five wires: Measure Pulse Output (PPS) from GPS - Yellow -> Pin 1 (DCD) on DB-9 Transmit - White -> Pin 2 (RXD) Receive - Green -> Pin 3 (TXD), ground black -> pin 5 (GND) and power red -> pin 9. As a replacement I used a shielded CAT 6 cable and connected each of the pairs together at both ends and thus got four connections: PPS, transmit, receive and power supply (90 mA). I then connected all the black wires together at the end of the GPS cable and used the ground wire as ground by connecting it to pin 5 on the DB-9 at the other end. For mounting, there is a brass recess with a metric (M3) thread on the underside of the 18x LVC. I've also installed a 1-Port Low Profile StarTech.com PEX1S553LP Native RS232 PCI Express serial card with 16550 UART card in a Windows 7 PC, which is only used to run firmware updates etc on the GPS if needed (since it is not possible to run on Linux). My 18x LVC has been updated to version 3.80 (March 26, 2012). For what it's worth, my time1 setting in ntp.conf is 0.035. This gives me the lowest offset and jitter for PPS. Works like a charm, with extremely low PPS latency (accurate to a few microseconds).