> There's no particular reason that a GPS carrier phase disciplined OCXO > need be particularly expensive unless of course it incorporates an > Oscilloquartz 8607 with ultra low adev specs. > Suitable receivers seem to be readily available. The only major > complication is the need to phase lock their local oscillator to the > OCXO being disciplined.
Bruce, Can you explain this a bit more? I know you often mention this point. But it seems there must be something more to it; otherwise we all would have seen low-cost carrier-phase GPSDO products on the market over the past 15 years... Instead there are only a few, they are all very expensive, and none (?) of them use standard OEM GPS receivers. I ran a carrier-phase Ashtech Z12T here for a while. It was my understanding that the reason it performed so well was a combination of carrier-phase tracking, L1/L2 choke ring antenna, phase stabilized cables, and dual band receiver. It also required an external free-running 20 MHz laboratory reference (I used a 4x multiplier off a cesium or maser). Further, one used it by collecting raw RINEX data and daily sent the batch files to be post-processed for two weeks. It would be interesting to know how much each of these five pieces contributed to its overall performance. My hunch is cheap OEM timing receiver carrier-phase measurement alone is not enough. /tvb _______________________________________________ time-nuts mailing list -- [email protected] To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
