[time-nuts] Stability question

[Jack Davis]

I have a Datum Exactime ET-6000TCXO that I use to lock all my test equipment to 10 MHz.  My GPS antenna is approximately 200 feet from the receiver and I have intermittent GPS signal levels and associated unlocking of my ET-6000TCXO.  I have tried using bigger less loss coax cable but its just not enough to make it reliable.

I see there is a Symmetricom Kit 142.6150 consisting of a model 140-615 GPS antenna / downconverter and a model 150-615 upconverter available to allow longer runs of coax cable.  From what I can tell there is a local oscillator in the antenna that down converts the 1,575.42 MHz GPS signal to 4.092 MHz for lower cable loss.  The up converter on the receiver side apparently another local oscillator that up converts the 4.092 MHz IF to 1,575.42 MHz.

My question is: will the two local oscillators and the up and down conversion cause phase noise or frequency instability of the GPS signals into my ET-6000TCXO?  It does have some sort of flywheel correction internally but is it enough to keep the 10 MHz timebase stable?

Thanks,
Jack  K6YC