Chris Hastie wrote: > Perhaps drifting a little OT, but I suspect there will be people here > who have a lot more idea than I do about this. > > I'm toying with the idea of getting a Garmin GPS18 LVC. The problem I > have is that all the places I can reasonably put machines to connect it > to are on the north side of the building, which is at a latitude of > 52.275036 N. This gives me a rather limited view of bits of the sky that > GPS satellites actually turn up in. > > So what I want to know is how easy is it to extend the cable of these > units, and what are the implications? I'd probably need an extra 8 - 10m > to mount the unit on the south facing side of the building. Presumably > this will > > 1) Introduce losses. Will the signal still be useably strong? > 2) Introduce delays. What sort of level of delay is involved, and is it > significant compared to, say, those introduced by the OS (FreeBSD) > > Thanks for any help > I added 30 feet of old telephone cable to my GPS18LVC so I could get to the roof from the basement where the machines live and it's working fine. The only change I'm going to make to my setup is to add an RS232 level converter. Using the 5V outputs from the unit without level conversion is, I suspect, be causing a delay in the PC seeing the PPS edge. I'm going to add level converter and see if it makes a difference.
John _______________________________________________ timekeepers mailing list [email protected] https://fortytwo.ch/mailman/cgi-bin/listinfo/timekeepers
