[time-nuts] Best location for a GPS antenna...?

[Morris Odell]

I make GPS controlled clocks of various sorts and had been including cheap
Oncore receivers in them. In view of the inconvenience of needing a GPS
antenna feed for them I have decided to do something like this for local
distribution of the GPS sentence using little wireless modules such as the
Xbee or similar. I only need the RS-232 and pps and any small timing errors
introduced by the link won't be an issue for clock purposes. If you only use
the 1 pps for timing then the wireless modules could be a satisfactory
solution as errors will average out over the long period that is used for
disciplined oscillator controllers using the 1 pps.

Morris

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>   Buy a cheap Motorola Oncore receiver.   The
Oncore UT costs all of about $18 on eBay, buy four of them.    The
only signal you need to bring into the workroom from an Oncore is PPS
and that is "way easy" to do using fiber.   The other signals (rs232)
can be connected as needed and that is not often.  Then you build a
"standard" GSPDO in the workshop.    The initial cost is lower and the
engineering is simple (because only the PPS has to go over fiber)

The Oncore and GPSDO can give as good of result as the t-bolt.  It mostly
depends on how good the OCXO is, maybe even you build two GPSDOs running off
the same PPS the second one being  Rubinium based.
My $35 Rb can holdover for many weeks (at the level I need) if GPS is down.

Then you can install the t-bolt with an antenna you can disconnect and only
use the t-bolt now and then during good wearer to double check the GPSDO
that you can leave running 24x7


Chris Albertson
Redondo Beach, California