[time-nuts] Non-impedance matched antenna cables

Bruce Griffiths bruce.griffiths at xtra.co.nz
Fri Jun 13 10:11:47 EDT 2008

John Miles wrote:
> I don't believe the Thunderbolt is a carrier-phase receiver, is it?  If it's not, I'd be surprised if reflections make any difference.
> They don't seem to have gone out of their way to match either 50 or 75 ohms (see S11 plot of TAPR unit's antenna jack attached), unless the input Z changes when the unit's powered up.
> -- john, KE5FX 

Code phase is also affected by reflections, it all depends on the delay 
The Thunderbolt actually uses the carrier offset and drift rate as 
determined by the GPS receiver to discipline the OCXO so some sort of 
carrier phase measurement is likely to be involved.


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