[time-nuts] Absolute phase
k8yumdoober at gmail.com
Fri Nov 17 17:30:20 EST 2017
Might be interesting to try the same experiment both with the two
receivers on the same antenna and on the two different antennas.
In an ideal world I'd expect the time output(s) to track as well
either way, but it would be interesting to know how well this works
out in practice.
On Fri, Nov 17, 2017 at 4:15 PM, Arthur Dent <golgarfrincham at gmail.com>
> I have 2 antennas mounted on opposite ends of a roof and both of them feed
> commercial GPS DA/splitters and I can have as many as 10 receivers running
> at one time for testing. I have also used one of the high frequency type F
> TV passive splitters with one D.C. feed through and added 200-300 ohm
> resistors from the other outputs to ground. All this has seemed to work
> just fine but one of the older receivers apparently radiated its L.O. out
> the antenna coax and would interfere with a couple of other receivers I
> connected to the same DA.
> Connecting one 10 Mhz references to the external trigger on my scope and
> feeding 2 other GPS receivers to the input channels (all from the same
> antenna DA), I can watch the slow drift at 2 ns/div with respect to the
> trigger and sometimes one receiver drift one way as the other receiver
> drifts in the opposite direction and sometimes they drift the same way.
> drift is generally less than 2 ns but it is there and I assume it depends
> on what the internal ‘housekeeping’ of the receiver is doing and what birds
> they are using. So bottom line, they aren’t ‘locked’ to each other but are
> generally close.
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