Hi Putting the GPS on a fiber is fine, except you need a very large battery to keep it running. As soon as you have a power line up to it, you are right back to a metal conductor going to the wrong place(s).
Bob -----Original Message----- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of Attila Kinali Sent: Wednesday, April 11, 2012 4:37 PM To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] Best location for a GPS antenna...? On Wed, 11 Apr 2012 22:06:06 +0200 "Andrea Baldoni" <erm1ea...@ermione.com> wrote: > On Wed, Apr 11, 2012 at 10:19:40AM -0400, Bob Bownes wrote: > > > I do like the optical isolation suggestion. While less than optimal, > > perhaps the easiest solution is not to put the isolation between the t'bolt > > and the antenna, but to put the isolation between the t'bolt and the > > distribution amplifier. > > By the way, would it be possible to retransmit the GPS signal to isolate it? > > I mean, rx external antenna -> preamp -> tx directional internal antenna -> big > air gap -> rx directional internal antenna -> receiver. > The preamp would not be so power hungry as the full thunderbolt and maybe > it could be powered via a magnetic link (or a little solar panel with a > lamp illuminating it). Yes it would be. What you basically would need is to have a LNA, a bandpass filter and something that converts the voltage into light with very little noise. I think it would be easiest to down mix it first to 100MHz or so, then modulate a laser diode. In the house you'd have to mix it up to 1.5GHz again, of course. I have no clue whether that is feasible from the noise this whole circuitry will add or whether it would add so much noise that the receiver would have no chance... Attila Kinali -- Why does it take years to find the answers to the questions one should have asked long ago? _______________________________________________ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. _______________________________________________ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.