[time-nuts] Looking for advice to get a submillisecond setup

[Chris Albertson]

I think the easiest cable to make really long, if one must be long is the
antenna cable.   Use 100 meters of the kind of cable they use for cable
TV.  It comes double shield and has those compression type F connectors.
The cable can cary both the GPS signal and power for the amplifier that is
built into the antenna.  If the cable is very long, You would need another
in-line amplifier, again powered by the cable itself.

And yes, a gps antenna needs a good view of the sky, but the receiver
itself can be 100+ meters away from the antenna

On Thu, Feb 19, 2015 at 11:36 PM, Hal Murray <hmurray at megapathdsl.net>
wrote:

>
> jimlux at earthlink.net said:
> > So really, it's a matter of finding a place to put your Garmin receiver
> and
> > string a cable that's not too long to your *nix box running ntp.
>
> The "place to put your Garmin receiver" may not be as simple as it sounds.
>
> It needs a good view of the sky.  Roof is best, but a window may be good
> enough.
>
> A machine room is unlikely to work, even if you have a good window.  Too
> much
> EMI.  An elevator control room may have similar problems.
>
> I've thought about building a pair of boxes that would use standard CAT-5
> cables as an extender for this sort of thing.   4 pairs works nicely:
> power,
> TX, RX, PPS.
>
>
>
> > People have done it with a Rpi, if you want to go that route.
>
> The RPi has its Ethernet chip connected by USB so that adds a bit of fuzz.
>
> I should try to measure that.
>
>
> --
> These are my opinions.  I hate spam.
>
>
>
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-- 

Chris Albertson
Redondo Beach, California