[time-nuts] Z3805 hold-Over

Charles P. Steinmetz charles_steinmetz at lavabit.com
Sun Nov 11 21:44:19 UTC 2012


Doug wrote:

>I'll place a preamp in line to see if that increases the SS on the 
>3805 , maybe my problem is the GPS RX isn't well. Great point.

Note that most GPS engines (including the one in the 3805) report 
carrier-to-noise ratio (C/N), NOT signal strength.  C/N is a function 
mostly of the antenna location (and, to a lesser extent, the antenna 
itself).  So, while a preamp will raise the signal strength, it will 
also raise the noise strength, and the C/N -- which is what matters 
-- will not change much.  The cure is to find a better location for 
your antenna (and possibly get a better antenna, but location is the 
main thing).  If the only better location you have requires a long 
cable run, a preamp may help to offset cable attenuation.

Best regards,

Charles








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